Home > News > A Novel Small Molecule Drug Derived from Methimazole (Phenylmethimazole) that Targets Aberrant Toll-like Receptor Expression and Signaling for the Potential Prevention or Treatment of Diabetes Mellitus and Non-alcoholic Fatty Liver Disease
Diabetes, Liver Disorders
Read Time: 11 mins

A Novel Small Molecule Drug Derived from Methimazole (Phenylmethimazole) that Targets Aberrant Toll-like Receptor Expression and Signaling for the Potential Prevention or Treatment of Diabetes Mellitus and Non-alcoholic Fatty Liver Disease

Published Online: April 27th 2015 US Endocrinology, 2015;11(1):17–23 DOI: http://doi.org/10.17925/USE.2015.11.1.17
Authors: Kelly D McCall, Frank L Schwartz
Quick Links:
Abstract
Article
Article Information
Abstract:
Overview

Toll-like receptors (TLRs) are pattern-recognition receptors located on the surface or within (endosome) immune cells (dendritic), whose function is to recognize pathogens from the environment and mediate both the innate and acquired immune responses. Environmental activation of TLRs in nonimmune cells is now recognized as a significant pathway that mediates the loss of self-tolerance in autoimmune diseases, as well as inflammationinduced cell damage in many chronic diseases. We have developed a small molecule drug derived from methimazole, phenylmethimazole (C10), which interferes with the environmental induction of TLR signaling in nonimmune cells and is an active inhibitor of pathologic inflammation in many animal disease models. This article has been written to introduce clinicians to TLR function and the potential therapeutic role that their inhibition could play in many inflammatory/autoimmune diseases, including diabetes and nonalcoholic fatty liver disease (NAFLD).

Keywords

Toll-like receptors, diabetes, nonalcoholic fatty liver disease, inflammation, TLR antagonists

Article:

There are two major forms of diabetes mellitus, type 1 (T1DM) and type 2 (T2DM), with the latter being the most common form, accounting for over 90 % of cases.1 Further, with the epidemic of obesity, T2DM can occur at any age, including children and adolescents,1 affecting nearly 30 million in the US and 400 million worldwide.2 Although there are multiple medications available to treat T2DM, overall success is poor given that no medication addresses the multiple abnormalities associated with T2DM and changes in diet and lifestyle are extremely difficult to achieve.3 T1DM occurs more frequently in children, adolescents, and young adults and is caused by destruction of the insulin-producing beta cells of the pancreas.4,5 Currently there is no cure for T1DM and it requires lifelong insulin replacement.6 The prevalence of both forms of DM are increasing worldwide1,4 and are associated with increased risk for multiple long-term diabetes complications, premature disability, and early death.7–10 Nonalcoholic fatty liver disease (NAFLD) is even more common than T2DM affecting 75 % of all obese individuals, is the leading cause of cirrhosis, end-stage liver disease, and primary hepatocellular cancer in the US.11,12 Treatment of NAFLD is also difficult due to similar lifestyle change requirements,13and many of the medications used to reduce hepatic inflammation and fibrosis are potentially hepatotoxic themselves.14–16 Thus, all three of these diseases (as well as atherosclerosis and many cancers) have a large inflammatory/immune component, which is driven by environmental insults to the body (viruses, dietary components such as high saturated fats, or overconsumption of high-fructose corn syrup [HFCS], etc.) Much contemporary research is directed at suppressing the various inflammatorypathways involved in these diseases without impairing the normal immune response or damaging the tissues we are attempting to protect.

Toll-like receptors (TLRs) are pattern-recognition receptors that were originally identified on the surface or within (endosome) immune cells (dendritic and monocytes/macrophages) that recognize various pathogen-associated molecular patterns (PAMPs) from the environment.17,18 Recognition of these PAMPS by the various TLRs protect mammals from pathogenic organisms, such as bacteria, viruses, or protozoa and are important mediators of both the initial “innate” immune response to the molecular products of these organisms as well as the “adaptive” or memory immune response.18 TLRs were consequently found to be expressed in multiple nonimmune cell types including the epithelial cells lining the gastrointestinal tract,19 endothelium,20 liver,21,22 adipocytes,23,24 and even pancreatic beta cells.25 TLR also recognize endogenous ligands released by injured cells (from infection, inflammation, radiation, etc.), and these are termed damage-associated molecular patterns (DAMPs). Ten different TLRs have now been identified in humans,as well as many of their exogenous and/or endogenous ligands (except TLR 10 whose ligands are not yet known), as well as some of the diseases to which they are linked (see Table 1).

We first became interested in TLR function when attempting to determine the molecular mechanism of action of the drug phenylmethimazole (C10), which is a derivative of the antithyroid medication methimazole. Methimazole is commonly used to treat hyperthyroidism by blocking thyroxine biosynthesis in thyrocytes; however, methimazole was also shown to downregulate expression of the major histocompatibility (MHC) genes, I and II,26,27 which suggested it might also possess anti-inflammatory and immunoregulatory activity. C10 (which does not have any effect on thyroxine biosynthesis) was subsequently found to regulate the expression of MHC genes I and II,25 to block TLR3, TLR4/TLR2, and TLR9 expression, and suppress inflammation in a variety of diseases25,28,29 including TLR3 in T1DM,30,31 TLR4/TLR2 in T2DM,24 and, most recently, TLR4/TLR2 (likely) in NAFLD.

Toll-like Receptor Function in the Normal Immune Response
TLRs are single, transmembrane, noncatalytic receptors, which are located either on the cell surface or internally on the endosome.18,32 In general, the TLRs on the cell surface, such as TLR2 and TLR4, recognize Gramnegative and Gram-positive PAMPs (lipoproteins, lipopolysaccharides, and peptidoglycans), while endosomal TLR3 functions to recognize injected viral nucleic acids. TLRs also recognize endogenous mammalian DAMPs, such as the intracellular lipoproteins, lipopolysaccharides, and peptidoglycans, or the self-DNA released following infection and/or other damaging environmental insults such as radiation, chemicals, etc.19,20,33–37 Thus, TLR normally function to protect an organism from infections and help clear debris following tissue damage.

Toll-like Receptors in Autoimmune and Aberrant Inflammatory Responses
Chronic TLR activation and signaling in both immune and nonimmune cellsby environmental antigens are now also thought to play critical roles in the induction of many chronic inflammatory diseases, the initiation and/ or perpetuation of autoimmunity (loss of self-recognition), as well as contribute to oncogenesis, tumor growth, and spread.38 Much of our recent research has focused on the roles of TLR3 and TLR2/TLR4 in the viralinduction of T1DM and high-fat diet (HFD) or free fatty acid (FFA) induction of obesity, insulin resistance (IR), T2DM, and, more recently, NAFLD, respectively. These three TLRs and their signaling pathways are depicted in Figure 1. Once TLRs bind to their respective ligands, they dimerize andintracellular adaptor molecules regulate their downstream signaling. The primary effector molecules of TLR2 and TLR4 are the transcription factors: nuclear factor kappa-light-chain-enhancer of activated B cells (NFkB) and interferon regulatory factor (IRF)-5 while for TLR3 they are NFkB and IRF3. These transcription factors then enter the cell nucleus and activate genes responsible for the production of the type I interferons, and proinflammatory cytokines and chemokines involved in both the innate immune responses, as well as upregulate MHC genes I and II, which are critical for the development of antigen-specific adaptive immunity.39,40

The Role of Viruses in the Pathogenesis of T1DM
T1DM results from beta (β) cell destruction and the consequent loss of endogenous insulin secretion.41–43 There are major genetic and environmental factors associated with the risk for T1DM. The vast majority of cases (85–90 %) are due to the initiation (environmental) of a predominately T-cell-mediated, gradual (months to years) autoimmune destruction of β cells (T1DM-A).44 The etiology of the other 10–15 % cases, which are more fulminant in onset, is unknown (T1DM-B); however, viruses are suspected as the principle environmental trigger of both forms.44 The strongest genetic link to T1DM-A are the class II HLA genes that control antigen presentation within the innate and acquired immune systems, while the genes responsible for T1DM-B are poorly characterized (only single-gene polymorphism associations). The HLA haplotypes DR3,4DQ8 exhibit the highest predictive risk for T1DM-A, but the genetic component with this strongest haplotype is thought to be responsible for only 40–50 % of the total risk,44–47 leaving environmental induction or acceleration as a major factor again in both forms of T1DM. While no single viral trigger for either form of T1DM has been clearly identified, the Coxsackie viruses (CBVs) are most closely associated with both forms, although influenza B, herpes simplex, and human herpes 6 virus have also been linked to both forms.48–53 In one study of children with new-onset T1DM, 39 % demonstrated a CBV-specific immunoglobulin (Ig)-M response compared with 5 % in age-matched controls.50 Some CVB strains have specific β cell tropism,54 indicating that these cells may be specific targets for them, and a large research effort to develop a CBV-based vaccination for prevention of T1DM is underway. Finally, serum from patients with new-onset T1DM possess a subset of anti-CBV antibodies that recognize β-cell autoantigens and are able to induce β-cell apoptosis in a pancreatic beta cell line.55

The Role of TLR3 in the Pathogenesis of T1DM
Both mouse and human pancreatic islets express multiple TLRs, including TLR2, TLR3, TLR4, and TLR9.56 TLR3 recognizes viral double-stranded RNA (dsRNA) while TLR9 recognizes self-DNA or unmethylated CpG DNA released from damaged β cells. Only TLR3 expression and signaling is upregulated in β cells by dsRNA, which is the intermediate nucleic acid generated during the life cycle of most enteroviruses35,56,57 and an illustration of the mechanism by which viruses inject their nucleic acids into β cells, their recognition by TLR3 and subsequent inflammatory signaling pathways involved in direct β cell destruction or the initiation of the autoimmune response directed at the β cell is depicted in Figure 2. Islets infected with CBV4 or treated with polyinosinic-polycytidylic acid (poly I:C) (a synthetic dsRNA that mimics host responses triggered by viral dsRNA) exhibit increased expression of TLR3.58,59 Interferon (IFN)-α or IFN-γ and interleukin (IL)-1β expressed by (TH1) cells and activated macrophages also stimulate increased expression of TLR3 in the virus-damaged islet cells.60–62 TLR9 are currently hypothesized to be involved in the recognition of self-antigens (self-DNA and unmethylated CpG DNA as well as intracellular proteins released from the damaged β cells) that then activate autoreactive B cells and promote the production of the islet cell autoantibodies (GAD65, I-A1, ZnT8, pre-proinsulin, and proinsulin), which are associated with T1DM-A.57 Interestingly, increased TLR4 signaling has also been demonstrated in the NOD mouse model of T1DM and several studies suggest that high mobility group protein B1 (HMGB1), which is associated with several inflammatory diseases and released from damaged and necrotic β cells, is its probable ligand and correlates with β-cell loss and onset of diabetes.63 Other studies have demonstrated that TLR4 deficiency accelerates T1DM in the NOD mouse.64 Moreover, TLR4 agonists and probiotics are protective for T1DM in the NOD mouse, which suggests that certain gut microbes may offer protection from pathogenic enteroviruses.65 Many studies have also reported increased TLR2 and TLR4 signaling in monocytes obtained from patients with T1DM. However, the increased monocyte signaling of TLR2 and TLR4 is probably a reflection of their upregulation from abnormal lipid metabolism rather than their involvement in the insulitis associated with progressive β-cell loss.

Pathogenesis of T2DM and NAFLD
T2DM and NAFLD are both chronic inflammatory diseases that are highly correlated with visceral obesity.66–68 Diets from industrialized countries include large volumes of processed foods, saturated fats, simple carbohydrates, and HFCS, which, coupled with decreased physical activity,is largely responsible for the epidemic of obesity and obesity-induced chronic inflammatory diseases including T2DM and NAFLD throughout the world.69 In the early stages of T2DM with weight gain and visceral obesityinduced IR, there is islet cell compensation with beta cell hyperplasia and hyperinsulinemia. Over time, however, this inevitably leads to progressive beta cell failure70 and insulin deficiency.71 The molecular pathogenesis of T2DM and NAFLD are depicted in Figure 3. Visceral adipocytes and associated macrophages are major contributors to these inflammatory processes via several signaling pathways. As visceral obesity increases (adipogenesis), both adipocytes and macrophages release increasing amounts of inflammatory adipokines/cytokines (TNF-α, IL-6, NF-κB, etc.)—a phenomenon that has been termed “low-grade sepsis” or “metabolic endotoxemia.”72 These adipokines/cytokines act locally to stimulate further adipogenesis as well as circulate to downregulate the insulin receptor (IR) function, which induces IR in the adipocyte as well as multiple other insulin target tissues (liver, skeletal muscle).73,74 Once the storage capacity of visceral adipocytes is saturated, endogenous FFAs and triglycerides (TGs) are released into the portal and peripheral circulation and exogenous dietary FFAs and TGs can no longer be cleared from the blood following meals. Excess circulating FFAs and TGs are subsequently ectopically deposited in these insulin target tissues, where they trigger the local release of the same inflammatory cytokines and chemokines (lipotoxicity), further exacerbating IR.75 The ectopic fat deposition in skeletal muscle results in the loss of mitochondrial function and consequent decreased oxidative phosphorylation, which also contributes to IR and interferes with weight loss.76 The ectopic fat deposited in the pancreas also induces β cell autophagy contributing to accelerated β cell death and ultimately insulin deficiency.77

Role of the Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 in the Pathogenesis of T2DM and NAFLD
Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) is a functional substrate of the IR in the liver and normally functions to promote insulin endocytosis and clearance from the circulation, occurring simultaneously with acquisition of visceral obesity and development of hyperinsulinemia from the pancreas. In the liver, which is the major regulator of glucose levels via hepatic storage (glycogen) or release (gluconeogenesis), there is also a major downregulation of CEACAM1.78 Thus, downregulation of CEACAM1 contributes further to IR and hyperinsulinemia,79 as well as NAFLD. Proof for the role of CEACAM1 in the pathogenesis of both T2DM and NAFLD was demonstrated in mouse studies using both a general CEACAM1 knockout and selective hepatic CEACAM1 knockout where the animals developed visceral obesity, IR, andsteatosis.80 Thus, ectopic fat deposition in the liver from excess portal (visceral) FFAs and TGs (lipotoxicity) and local CEACAM1 downregulation perpetuate a vicious cycle of inflammation, IR, and steatosis.81

The Role of TLR2/TLR4 Signaling in T2DM and NAFLD
Bacterial glycolipids and triacyl lipopeptides are the principle ligands for TLR2 while bacterial LPS is the principle exogenous ligand for TLR4. Their signaling pathways are demonstrated in Figure 1. Exogenous and endogenous FFAs (such as palmitate) induce pathologic TLR4 signaling in adipocytes, resulting in the release of TNF-α and IL-6, and the induction of IR.23,24 There is now increasing evidence that the pathologic expression of TLR2 and TLR4 in other insulin-sensitive tissues, including skeletal muscle,islets, and liver, are a major source of pro-inflammatory adipokine/cytokine (TNF-α, IL-6, NF-κB, etc.) production that leads to the “inflammatory storm” seen in T2DM and NAFLD.82–84 These same processes also contribute to as much as 40 % of the total risk for the chronic inflammation-induced, and obesity-associated malignancies (esophagus, pancreas, liver, colon, gall bladder, endometrium, breast, kidney, and thyroid).85

Gut Flora, TLRs, and Chronic Inflammatory Diseases
Many interesting studies linking changes in intestinal (gut) flora, TLR function, and chronic diseases such as inflammatory bowel disease but also including T1DM, T2DM, and NAFLD, have been reported recently in the literature.86,87 These studies suggest that different species of bacteria may contribute to the pathogenesis and/or protection from many diseases through activation and/or suppression of different TLR functions in gut epithelial cells and immune cells. Many early investigators suggested that the excessive TLR4 expression seen in obesity/T2DM was the result of gut bacteria-derived LPS and demonstrated that serum and tissue levels of LPS are higher in obesity/T2DM.88 Although fascinating in nature, a discussion of the gut microbiome, their linkage to TLR function, and to these diseases is beyond the scope of this discussion.

TLR as Therapeutic Targets
As soon as the functional role of TLRs were appreciated, they became potential therapeutic targets for various infectious diseases, allergic, immunologic and inflammatory diseases, sepsis, as well as the similar signaling pathways associated with cancer development and spread.89,90 The two principle sites for TLR targeting have been at their ligand binding sites or through inhibition of their downstream signaling pathways. Numerous strategies have been developed ranging from gene deletion to monoclonal antibodies. TLR-specific agonists and antagonists as well as inhibitors of the various TLR adaptor and regulatory molecules have also been described. A review of the current clinical trials using TLRdirected therapies highlighted at least eight compounds in 2014, wherein some used TLR3 and TLR9 agonists as vaccine adjuvants in HIV infections or chronic fatigue syndrome, while others used TLR7, TLR8, and TLR9 antagonists in various autoimmune diseases, and yet additional groups used TLR4 antagonists in sepsis trials.89,90

Novel Inhibitor of Pathologic TLR Expression and Signaling in T1DM, T2DM, and NAFLD
C10 is a derivative of the anti-thyroidal medication methimazole. Although it does not block thyroxine synthesis it does possess unique antiinflammatory properties, many of which are mediated through suppression of TLR signaling pathways in both immune and nonimmune cells.25 C10 was initially described when it was demonstrated that human thyrocytes from patients with Hashimoto’s thyroiditis expressed a functional TLR3.25 Moreover, TLR3 overexpression in these thyrocytes could be stimulated by viral infection (dsRNA), and reversed by C10 treatment.25 This suggested that C10 might possess both immunoregulatory and anti-tumor properties especially given the role of chronic inflammation in the transformation of Hashimoto’s thyroiditis into papillary thyroid cancer,91 as well as the impact of the immune response on survival in multiple cancers.92 C10 has now been shown to block TLR signaling in a variety of immunologic diseases as well as the basal expression of TLR3 and TLR4 in multiple cancers,24,28–31,93–95 suppressing tumor growth and spread in tissue cultures and tumor implants. Finally, in pancreatic cancer, C10 suppresses tumor growth and spread through the inhibition of TLR3-induced IRF3 dimerization, translocation to the nucleus, and gene transcription.96

Potential Use of C10 in T1DM
We have now demonstrated th at C10 prevents direct dsRNA poly I:Cinducedcytotoxicity (apoptosis) in two β cell culture lines (TC-6 and NIT-1) through inhibition of poly I:C-induced TLR3 signaling and the consequent inhibition of many of the cytokines and chemokines associated with T1DM including: CXCL10, IFN-β, TNF-α, and MHC class I gene expression in vitro.30 Pathologic IRF3 signaling via TLRs has previously been linked to both forms of diabetes. Next, we demonstrated that C10 protects 8 week-old NOD mice from CBV4 acceleration of diabetes, which usually occurs at 2 weeks postinfection. 31 We also demonstrated that 8-week-old TLR3 knockout (TLR3- /-) NOD mice, but not wild-type NOD mice, infected with CBV4 were also protected from the CBV4-induced insulitis and onset of diabetes at two weeks post-infection, confirming that this was a TLR3-mediated process.31 These findings are summarized in Figure 4. We suspect that activation of TLR3 signaling in β cells occurs through stimulation of the programmed cell death-1 ligand 1 (PD-L1) or changes in T-regulatory cell (CD4+CD25+ Foxp3+) or effector T-cell (CD8) ratios in islets during early development.97 Thus we are currently looking at the effects of C10 on TLR3 (+/+) and TLR3 (-/-) NOD mice to confirm this. We are also conducting studies to determine if C10 could preserve β cell function and insulin-secretory capacity following the initial onset of CVB4-induced hyperglycemia.31

Potential Use of C10 in T2DM
The observations that C10 (1) inhibits FFA (palmitate) induction of TLR signaling in 3T3 L1 pre-adipocytes; (2) inhibits palmitate-induced TLR4 expression and inflammatory signaling (IL-6 and iNos) in 3T3L1 adipocytes; (3) inhibits LPS-stimulated RAW2647 macrophages in culture;24 (4) blocks palmitate-induced Socs-3 upregulation and IRS-1 serine 307 phosphorylation, which mediate IR in 3T3L1 cells;24 and (5) prevents 3T3L1 cells from differentiating into adipocytes (Figure 5A [unpublished data]), suggested that it might be effective in reducing obesity-induced IR. To this end, we subsequently demonstrated that C10 treatment reversed IR, improved glucose intolerance wherein we observed improved area under the curve (AUC) in glucose tolerance tests (GTTs) as well as reduced elevated serum insulin, c-peptide, and leptin levels in high-fat diet-fed BL6 male mice, and if C10 is administered at the onset of a high-fat diet feeding(prevention study), animals gained less weight and it delayed the onset of T2DM in these mice (manuscript in preparation).

Potential Use of C10 in NAFLD
Anecdotally while conducting the T2DM prevention study using C10 in the high-fat diet-fed BL6 male mouse model of T2DM, we noted at necropsy that the C10-treated animals had normal-appearing livers while shamand vehicle-injected animals exhibited enlarged, pale livers, which was consequently found histologically to be steatosis resulting from the high fat diet feeding (see Figure 5B). We are currently studying C10 and other small-molecule TLR inhibitors that we have developed, which also prevent high-fat diet-induced steatosis (unpublished data) in both high-fat diet and high-fructose diet prevention studies, to confirm that these compounds do indeed possess potential therapeutic action in NAFLD.

Conclusions
T1DM, T2DM, and NAFLD are all inflammatory diseases in which TLRs mediate important inflammatory pathways. We have developed a small molecule, prototypical drug (C10), which significantly inhibits many TLRdependent inflammatory pathways and prevents viral-induction of T1DM in the NOD mouse model, and high-fat diet-induced visceral obesity, IR, and NAFLD in BL6 male mice fed a high-fat diet. Moreover, we have also developed an additional class of small molecule inhibitors of TLR signaling that may be more potent and have lower toxicities than C10, which we are currently testing for efficacy in preclinical animal models.

Article Information:
Disclosure

Both Kelly D McCall, PhD, and Frank L Schwartz, MD, FACE, and collaborators, are inventors of use patents submitted on behalf of Ohio University for
phenylmethimazole and composition of matter patents for derivatives mentioned in this article.

Correspondence

Frank L Schwartz, MD, 331 Academic Research Center, Athens, Ohio 45701, US. E: schwartf@ohio.edu

Support: This work was supported in part by a National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) grant (1R15 DK081192-01 to
KDM), the JO Watson Endowment for Diabetes Research (FLS), and the Ohio University Heritage College of Osteopathic Medicine.

Open Access: This article is published under the Creative Commons Attribution Noncommercial License, which permits any noncommercial use, distribution, adaptation, and
reproduction provided the original author(s) and source are given appropriate credit.

Received

2015-03-06

References

  1. Dabelea D, Mayer-Davis EJ, Saydah S, et al., Prevalence of type 1
    and type 2 diabetes among children and adolescents from 2001
    to 2009, JAMA, 2014;311:1778–86.
  2. Wild S, Roglic G, Green A, et al., Global prevalence of diabetes:
    estimates for the year 2000 and projections for 2030, Diabetes
    Care, 2004;27:1047–53.
  3. Inzucchi SE, Bergenstal RM, Buse JB, et al., Management of
    hyperglycemia in type 2 diabetes: a patient-centered approach:
    position statement of the American Diabetes Association (ADA)
    and the European Association for the Study of Diabetes (EASD),
    Diabetes Care, 2012;35:1364–79.
  4. Atkinson MA, Eisenbarth GS, Michels AW, Type 1 diabetes.
    Lancet, 2014;383:69–82.
  5. Soltesz G, Patterson CC, Dahlquist G, Worldwide childhood type
    1 diabetes incidence-what can we learn from epidemiology?,
    Pediatr Diabetes, 2007;8(Suppl. 6):6–14.
  6. Chiang JL, Kirkman MS, Laffel LM, Peters AL, Type 1 diabetes
    through the life span: a position statement of the American
    Diabetes Association, Diabetes Care, 2014;37:2034–54.
  7. Podrouzkova B, [The effect of intensive insulin therapy on
    specific long-term complications in type II diabetes], Vnitr Lek,
    1994;40:306–9.
  8. Brun E, Nelson RG, Bennett PH, et al., Diabetes duration and
    cause-specific mortality in the Verona Diabetes Study, Diabetes
    Care, 2000;23:1119–23.
  9. McBean AM, Li S, Gilbertson DT, Collins AJ, Differences in
    diabetes prevalence, incidence, and mortality among the elderly
    of four racial/ethnic groups: whites, blacks, hispanics, and
    Asians, Diabetes Care, 2004;27:2317–24.
  10. The Diabetes Control and Complication Group: The effect of
    intensive treatment of diabetes on the developement and
    progression of long-term complications in insulin dependent
    diabetes mellitus, N Engl J Med, 1993;329:977–866.
  11. Bellentani S, Scaglioni F, Marino M, Bedogni G, Epidemiology of
    non-alcoholic fatty liver disease, Dig Dis, 2010;28:155–61.
  12. Browning JD, Szczepaniak LS, Dobbins R, et al., Prevalence of
    hepatic steatosis in an urban population in the United States:
    impact of ethnicity, Hepatology, 2004;40:1387–95.
  13. Huang MA, Greenson JK, Chao C, et al., One-year intense
    nutritional counseling results in histological improvement in
    patients with non-alcoholic steatohepatitis: a pilot study, Am J
    Gastroenterol, 2005;100:1072–81.
  14. Chalasani N, Younossi Z, Lavine JE, et al., The diagnosis and
    management of non-alcoholic fatty liver disease: practice
    guideline by the American Gastroenterological Association,
    American Association for the Study of Liver Diseases,
    and American College of Gastroenterology, Hepatology,
    2012;142:1592–609.
  15. Bugianesi E, Gentilcore E, Manini R, et al., A randomized
    controlled trial of metformin versus vitamin E or prescriptive
    diet in nonalcoholic fatty liver disease, Am J Gastroenterol,
    2005;100:1082–90.
  16. Sanyal AJ, Chalasani N, Kowdley KV, et al., Pioglitazone, vitamin
    E, or placebo for nonalcoholic steatohepatitis, N Engl J Med,
    2010;362:1675–85.
  17. Takeda K, Akira S, Toll receptors and pathogen resistance, Cell
    Microbiol, 2003;5:143–53.
  18. Takeda K, Kaisho T, Akira S, Toll-like receptors, Annu Rev
    Immunol, 2003;21:335–76.
  19. Ortega-Cava CF, Ishihara S, Rumi MA, et al., Strategic
    compartmentalization of Toll-like receptor 4 in the mouse gut,
    J Immunol, 2003;170:3977–85.
  20. Andonegui G, Bonder CS, Green F, et al., Endotheliumderived
    Toll-like receptor-4 is the key molecule in LPSinduced
    neutrophil sequestration into lungs, J Clin Invest,
    2003;111:1011–1020.
  21. Liu S, Gallo DJ, Green AM, et al., Role of toll-like receptors in
    changes in gene expression and NF-kappa B activation in
    mouse hepatocytes stimulated with lipopolysaccharide, Infect
    Immun, 2002;70:3433–42.
  22. Paik YH, Schwabe RF, Bataller R, et al., Toll-like receptor 4
    mediates inflammatory signaling by bacterial lipopolysaccharide
    in human hepatic stellate cells, Hepatology, 2003;37:1043–55.
  23. Shi H, Kokoeva MV, Inouye K, et al., TLR4 links innate immunity
    and fatty acid-induced insulin resistance, J Clin Invest,
    2006;116:3015–25.
  24. McCall KD, Holliday D, Dickerson E, et al., Phenylmethimazole
    blocks palmitate-mediated induction of inflammatory cytokine
    pathways in 3T3L1 adipocytes and RAW 264.7 macrophages,
    J Endocrinol, 2010;207:343–353
  25. Harii N, Lewis C, Vasko V, et al., Thyrocytes express a functional
    toll-like receptor 3(TLR3): Overexpression can be induced
    by viral infection, reversed by Phenylmethimazole, and is
    associated with Hashimoto’s autoimmune thyroiditis, Mol Endo,
    2003;19:1231–50.
  26. Montani V, Shong M, Taniguchi SI, et al., Regulation of major
    histocompatibility class II gene expression in FRTL-5 thyrocytes:
    opposite effects of interferon and methimazole, Endocrinology,
    1998;139:290–302
  27. Balducci-Silano PL, Suzuki K, Ohta M, et al., Regulation of major
    histocompatibility (MHC) class II human leukocyte antigen-DR
    alpha gene expression in thyrocytes by single strand binding
    protein-1, a transcription factor that also regulates thyrotropin receptor and MHC class I gene expression, Endocrinology,
    1998;139:2300–13.
  28. McCall KD, Harii N, Lewis CJ, et al., High basal levels of
    functional toll-like receptor 3 (TLR3) and noncanonical Wnt5a
    are expressed in papillary thyroid cancer and are coordinately
    decreased by phenylmethimazole together with cell
    proliferation and migration, Endocrinology, 2007;148:4226–37.
  29. Schwartz AL, Malgor R, Dickerson E, et al., Phenylmethimazole
    decreases Toll-like receptor 3 and noncanonical Wnt5a
    expression in pancreatic cancer and melanoma together
    with tumor cell growth and migration, Clin Cancer Res,
    2009;15:4114–22.
  30. McCall KD, Schmerr MJ, Thuma JR, et al., Phenylmethimazole
    suppresses dsRNA-induced cytotoxicity and inflammatory
    cytokines in murine pancreatic beta cells and blocks viral
    acceleration of type 1 diabetes in NOD mice, Molecules,
    2013;18:3841–58.
  31. McCall KD, Thuma JR, Courreges MC, et al., Toll-Like Receptor
    3 Is Critical for Coxsackievirus B4-Induced Type 1 Diabetes in
    Female NOD Mice, Endocrinology, 2015;156:453–61.
  32. Gay NJ, Gangloff M, Structure of toll-like receptors, Handb Exp
    Pharmacol, 2008;181–200.
  33. Nasu K, Narahara H, Pattern recognition via the toll-like receptor
    system in the human female genital tract, Mediators Inflamm,
    2010:976024.
  34. Yamasaki K, Kanada K, Macleod DT, et al., TLR2 expression
    is increased in rosacea and stimulates enhanced serine
    protease production by keratinocytes, J Invest Dermatol,
    2010;131:688–697
  35. Giarratana N, Penna G, Amuchastegui S, et al., A vitamin D
    analog down-regulates proinflammatory chemokine production
    by pancreatic islets inhibiting T cell recruitment and type 1
    diabetes development, J Immunol, 2004;173:2280–7.
  36. Schroder NW, Maurer M, The role of innate immunity in asthma:
    leads and lessons from mouse models, Allergy, 2007;62:579–90.
  37. Ayari C, Bergeron A, LaRue H, et al., Toll-like receptors in normal
    and malignant human bladders, J Urol, 2011;185:1915–21.
  38. O’Neill LA, Golenbock D, Bowie AG, The history of toll-like
    receptors – redefining innate immunity, Nat Rev Immunol,
    2013;13:453–60.
  39. Schnare M, Barton GM, Holt AC, et al., Toll-like receptors control
    activation of adaptive immune responses, Nat Immunol,
    2001;2:947–50.
  40. Akira S, Takeda K, Kaisho T, Toll-like receptors: critical
    proteins linking innate and acquired immunity, Nat Immunol,
    2001;2:675–80.
  41. Cnop M, Welsh N, Jonas JC, et al., Mechanisms of pancreatic
    beta-cell death in type 1 and type 2 diabetes: many differences,
    few similarities, Diabetes, 2005;54(Suppl. 2):S97–107.
  42. Zipris D, Innate immunity and its role in type 1 diabetes,
    Curr Opin Endocrinol Diabetes Obes, 2008;15:326–31.
  43. Wang PY, Ma W, Park JY, et al., Increased oxidative metabolism
    in the Li-Fraumeni syndrome, N Engl J Med, 2013;368:1027–32.
  44. Bluestone JA, Herold K, Eisenbarth G, Genetics, pathogenesis
    and clinical interventions in type 1 diabetes, Nature,
    2010;464:1293–300.
  45. Rich SS, Akolkar B, Concannon P, et al., Current status and
    the future for the genetics of type I diabetes, Genes Immun,
    2009;10(Suppl. 1):S128–31.
  46. Noble JA, Valdes AM, Varney MD, et al., HLA class I and genetic
    susceptibility to type 1 diabetes: results from the Type 1
    Diabetes Genetics Consortium, Diabetes, 2010;59:2972–9.
  47. Lipponen K, Gombos Z, Kiviniemi M, et al., Effect of HLA class I
    and class II alleles on progression from autoantibody positivity
    to overt type 1 diabetes in children with risk-associated class II
    genotypes, Diabetes, 2010;59:3253–6.
  48. Stene LC, Oikarinen S, Hyoty H, et al., Enterovirus infection
    and progression from islet autoimmunity to type 1 diabetes:
    the Diabetes and Autoimmunity Study in the Young (DAISY),
    Diabetes, 2010;59:3174–80.
  49. Yoon JW, Austin M, Onodera T, Notkins AL, Isolation of a virus
    from the pancreas of a child with diabetic ketoacidosis,
    N Engl J Med, 1979;300:1173–9.
  50. King ML, Shaikh A, Bidwell D, et al., Coxsackie-B-virus-specific
    IgM responses in children with insulin-dependent (juvenileonset;type I) diabetes mellitus, Lancet, 1983;1:1397–9.
  51. Tapia G, Cinek O, Rasmussen T, et al., Longitudinal study of
    parechovirus infection in infancy and risk of repeated positivity
    for multiple islet autoantibodies: the MIDIA study. Pediatr
    Diabetes, 2011;12:58–62.
  52. Knip M, Veijola R, Virtanen SM, et al., Environmental triggers
    and determinants of type 1 diabetes, Diabetes, 2005;54(Suppl.
    2):S125–36.
  53. Filippi CM, von Herrath MG, Viral trigger for type 1 diabetes:
    pros and cons, Diabetes, 2008;57:2863–71.
  54. Ylipaasto P, Klingel K, Lindberg AM, et al., Enterovirus infection
    in human pancreatic islet cells, islet tropism in vivo and
    receptor involvement in cultured islet beta cells, Diabetologia,
    2004;47:225–39.
  55. Bason C, Lorini R, Lunardi C, et al., In type 1 diabetes a subset
    of anti-coxsackievirus B4 antibodies recognize autoantigens
    and induce apoptosis of pancreatic beta cells, PLoS One,
    2013;8:e57729.
  56. Eizirik DL, Colli ML, Ortis F, The role of inflammation in insulitis
    and beta-cell loss in type 1 diabetes, Nat Rev Endocrinol,
    2009;5:219–26.
  57. Wen L, Peng J, Li Z, Wong FS, The effect of innate immunity on
    autoimmune diabetes and the expression of Toll-like receptors
    on pancreatic islets, J Immunol, 2004;172:3173–80.
  58. Rasschaert J, Ladriere L, Urbain M, et al., Toll-like receptor 3 and
    STAT-1 contribute to double-stranded RNA+ interferon-gammainduced
    apoptosis in primary pancreatic beta-cells, J Biol Chem,
    2005;280:33984–91.
  59. Ylipaasto P, Kutlu B, Rasilainen S, et al., Global profiling of
    coxsackievirus- and cytokine-induced gene expression in
    human pancreatic islets, Diabetologia, 2005;48:1510–22.
  60. Liu D, Cardozo AK, Darville MI, Eizirik DL, Double-stranded RNA
    cooperates with interferon-gamma and IL-1 beta to induce both
    chemokine expression and nuclear factor-kappa B-dependent
    apoptosis in pancreatic beta-cells: potential mechanisms for
    viral-induced insulitis and beta-cell death in type 1 diabetes
    mellitus, Endocrinology, 2002;143:1225–34.
  61. Tanaka S, Nishida Y, Aida K, et al., Enterovirus infection, CXC
    chemokine ligand 10 (CXCL10), and CXCR3 circuit: a mechanism
    of accelerated beta-cell failure in fulminant type 1 diabetes,
    Diabetes, 2009;58:2285–91.
  62. Gur C, Porgador A, Elboim M,et al., The activating receptor
    NKp46 is essential for the development of type 1 diabetes,
    Nat Immunol, 2010;11:121–8.
  63. Li M, Song L, Gao X, et al., Toll-like receptor 4 on islet beta cells
    senses expression changes in high-mobility group box 1 and
    contributes to the initiation of type 1 diabetes, Exp Mol Med,
    2010;44:260–7.
  64. Gulden E, Ihira M, Ohashi A, et al., Toll-like receptor 4 deficiency
    accelerates the development of insulin-deficient diabetes in
    non-obese diabetic mice, PLoS One, 2013;8:e75385.
  65. Calcinaro F, Dionisi S, Murinaro M, et al., Oral probiotic
    admisitration induces interleukin-10 production and prevents
    spontaneous autoimmune diabetes in the non-obese diabetic
    mouse, Diabetologia, 2005;48:1565–75.
  66. Boden G, She P, Mozzoli M, et al., Free fatty acids produce
    insulin resistance and activate the proinflammatory nuclear
    factor-kappaB pathway in rat liver, Diabetes, 2005;54:3458–65.
  67. Curat CA, Wegner V, Sengenes C, et al., Macrophages in human
    visceral adipose tissue: increased accumulation in obesity and
    a source of resistin and visfatin, Diabetologia, 2006;49:744–7.
  68. Glass CK, Olefsky JM, Inflammation and lipid signaling in the
    etiology of insulin resistance, Cell Metab, 2012;15:635–45.
  69. Sawada K, Ohtake T, Hasebe T, et al., Augmented hepatic
    Toll-like receptors by fatty acids trigger the pro-inflammatory
    state of non-alcoholic fatty liver disease in mice, Hepatol Res,
    2014;44:920–34.
  70. Marchetti P, Bugliani M, Boggi U, et al., The pancreatic beta cells
    in human type 2 diabetes, Adv Exp Med Biol, 2012;771:288–9.
  71. Kahn SE, Clinical review 135: The importance of beta-cell failure
    in the development and progression of type 2 diabetes,
    J Clin Endocrinol Metab, 2001;86:4047–58.
  72. Kolyva AS, Zolota V, Mpatsoulis D, et al., The role of obesity
    in the immune response during sepsis, Nutr Diabetes,
    2014;4:e137.
  73. Paz K, Hemi R, LeRoith D, et al., A molecular basis for insulin
    resistance. Elevated serine/threonine phosphorylation of
    IRS-1 and IRS-2 inhibits their binding to the juxtamembrane
    region of the insulin receptor and impairs their ability to
    undergo insulin-induced tyrosine phosphorylation, J Biol Chem,
    1997;272:29911–8.
  74. Ragheb R, Shanab GM, Medhat AM, et al., Free fatty acidinduced
    muscle insulin resistance and glucose uptake
    dysfunction: evidence for PKC activation and oxidative stressactivated
    signaling pathways, Biochem Biophys Res Commun,
    2009;389:211–6.
  75. Kashyap SR, Belfort R, Berria R, et al., Discordant effects of a
    chronic physiological increase in plasma FFA on insulin signaling
    in healthy subjects with or without a family history of type 2
    diabetes, Am J Physiol Endocrinol Metab, 2004;287:E537–46.
  76. . Frayn KN, Arner P, Yki-Jarvinen H, Fatty acid metabolism in
    adipose tissue, muscle and liver in health and disease, Essays
    Biochem, 2006;42:89–103.
  77. Sharma RB, Alonso LC, Lipotoxicity in the pancreatic beta cell:
    not just survival and function, but proliferation as well?, Curr
    Diab Rep, 2014;14:492.
  78. Poy MN, Yang Y, Rezaei K, et al., CEACAM1 regulates insulin
    clearance in liver, Nat Genet, 2002;30:270–6.
  79. Najjar SM, Regulation of insulin action by CEACAM1, Trends
    Endocrinol Metab, 2002;13:240–5.
  80. Lee SJ, Heinrich G, Fedorova L, et al., Development of
    nonalcoholic steatohepatitis in insulin-resistant liver-specific
    S503A carcinoembryonic antigen-related cell adhesion
    molecule 1 mutant mice, Gastroenterology, 2008;135:2084–95.
  81. Zambo V, Simon-Szabo L, Szelenyi P, et al., Lipotoxicity in the
    liver, World J Hepatol, 2013;5:550–7.
  82. Glaros T, Chang S, Gilliam E, et al., Causes and consequences of
    low grade endotoxemia and inflammatory disease, Front Biosci
    (Elite Ed), 2013;S5:754–65.
  83. Lassenius MI, Pietilainen KH, Kaartinen K, et al., Bacterial
    endotoxin activity in human serum is associated with
    dyslipidemia, insulin resistance, obesity, and chronic
    inflammation, Diabetes Care, 2011;34:1809–15.
  84. Pussinen PJ, Havulinna AS, Lehto M, Set al., Endotoxemia is
    associated with an increased risk of incident diabetes, Diabetes
    Care, 2011;34:392–7.
  85. Gilbert CA, Slingerland JM, Cytokines, obesity, and cancer: new
    insights on mechanisms linking obesity to cancer risk and
    progression, Annu Rev Med, 2013;64:45–57.
  86. Sanz Y, Moya-Perez A, Microbiota, inflammation and obesity,
    Adv Exp Med Biol, 2014817:291–317.
  87. Arslan N, Obesity, fatty liver disease and intestinal microbiota.
    World J Gastroenterol 201420:16452–63.
  88. Kim KA, Gu W, Lee IA, et al., High fat diet-induced gut microbiota
    exacerbates inflammation and obesity in mice via the TLR4
    signaling pathway, PLoS One, 2012;7:e47713.
  89. Junquera EC, Mateos-Hernandez L, de la Fuente J, de la
    Lastra JM, Recent advances in the development of antiinfective
    prophylactic and/or therapeutic agents based on
    Toll-Like Receptor (TLRs). Recent Pat Antiinfect Drug Discov,
    2014;9:14–24.
  90. Zuany-Amorim C, Hastewell J, Walker C, Toll-like receptors as
    potential therapeutic targets for multiple diseases, Nat Rev Drug
    Discov, 2002;1:797–807.
  91. Cunha LL, Ferreira RC, Marcello MA, et al., Clinical and
    pathological implications of concurrent autoimmune
    thyroid disorders and papillary thyroid cancer, J Thyroid Res,
    2011;2011:387062.
  92. Mantovani A, Allavena P, Sica A, Balkwill F, Cancer-related
    inflammation, Nature, 2008;454:436–44.
  93. McCall K, Benencia F, Kohn L, et al., Toll-like receptors as novel
    therapeutic targets for the treatment of pancreatic cancer. In:
    Srivastava S, ed., Pancreatic Cancer Molecular Mechanism and
    Targets, Croatia: InTech, 2012;361–98.
  94. Courreges MC, Kantake N, Goetz DJ, et al., Phenylmethimazole
    blocks dsRNA-induced IRF3 nuclear translocation and
    homodimerization, Molecules, 2012;17:12365–77.
  95. Benavides U, Gonzalez-Murguiondo M, Harii N, et al.,
    Phenylmethimazole inhibits production of proinflammatory
    mediators and is protective in an experimental model of
    endotoxic shock*, Crit Care Med, 2011;40:886–94.
  96. Courreges MC, Kantake N, Goetz DJ, et al., Phenylmethimazole
    blocks dsRNA-induced IRF3 nuclear translocation and
    homodimerization, Molecules, 2012;17:12365–77.
  97. Shevach EM, Mechanisms of foxp3+ T regulatory cell-mediated
    suppression, Immunity, 2009;30:636–45.

Further Resources

Share this Article
Related Content In Liver Disorders
  • Copied to clipboard!
    accredited arrow-down-editablearrow-downarrow_leftarrow-right-bluearrow-right-dark-bluearrow-right-greenarrow-right-greyarrow-right-orangearrow-right-whitearrow-right-bluearrow-up-orangeavatarcalendarchevron-down consultant-pathologist-nurseconsultant-pathologistcrosscrossdownloademailexclaimationfeedbackfiltergraph-arrowinterviewslinkmdt_iconmenumore_dots nurse-consultantpadlock patient-advocate-pathologistpatient-consultantpatientperson pharmacist-nurseplay_buttonplay-colour-tmcplay-colourAsset 1podcastprinter scenerysearch share single-doctor social_facebooksocial_googleplussocial_instagramsocial_linkedin_altsocial_linkedin_altsocial_pinterestlogo-twitter-glyph-32social_youtubeshape-star (1)tick-bluetick-orangetick-red tick-whiteticktimetranscriptup-arrowwebinar Department Location NEW TMM Corporate Services Icons-07NEW TMM Corporate Services Icons-08NEW TMM Corporate Services Icons-09NEW TMM Corporate Services Icons-10NEW TMM Corporate Services Icons-11NEW TMM Corporate Services Icons-12Salary £ TMM-Corp-Site-Icons-01TMM-Corp-Site-Icons-02TMM-Corp-Site-Icons-03TMM-Corp-Site-Icons-04TMM-Corp-Site-Icons-05TMM-Corp-Site-Icons-06TMM-Corp-Site-Icons-07TMM-Corp-Site-Icons-08TMM-Corp-Site-Icons-09TMM-Corp-Site-Icons-10TMM-Corp-Site-Icons-11TMM-Corp-Site-Icons-12TMM-Corp-Site-Icons-13TMM-Corp-Site-Icons-14TMM-Corp-Site-Icons-15TMM-Corp-Site-Icons-16TMM-Corp-Site-Icons-17TMM-Corp-Site-Icons-18TMM-Corp-Site-Icons-19TMM-Corp-Site-Icons-20TMM-Corp-Site-Icons-21TMM-Corp-Site-Icons-22TMM-Corp-Site-Icons-23TMM-Corp-Site-Icons-24TMM-Corp-Site-Icons-25TMM-Corp-Site-Icons-26TMM-Corp-Site-Icons-27TMM-Corp-Site-Icons-28TMM-Corp-Site-Icons-29TMM-Corp-Site-Icons-30TMM-Corp-Site-Icons-31TMM-Corp-Site-Icons-32TMM-Corp-Site-Icons-33TMM-Corp-Site-Icons-34TMM-Corp-Site-Icons-35TMM-Corp-Site-Icons-36TMM-Corp-Site-Icons-37TMM-Corp-Site-Icons-38TMM-Corp-Site-Icons-39TMM-Corp-Site-Icons-40TMM-Corp-Site-Icons-41TMM-Corp-Site-Icons-42TMM-Corp-Site-Icons-43TMM-Corp-Site-Icons-44TMM-Corp-Site-Icons-45TMM-Corp-Site-Icons-46TMM-Corp-Site-Icons-47TMM-Corp-Site-Icons-48TMM-Corp-Site-Icons-49TMM-Corp-Site-Icons-50TMM-Corp-Site-Icons-51TMM-Corp-Site-Icons-52TMM-Corp-Site-Icons-53TMM-Corp-Site-Icons-54TMM-Corp-Site-Icons-55TMM-Corp-Site-Icons-56TMM-Corp-Site-Icons-57TMM-Corp-Site-Icons-58TMM-Corp-Site-Icons-59TMM-Corp-Site-Icons-60TMM-Corp-Site-Icons-61TMM-Corp-Site-Icons-62TMM-Corp-Site-Icons-63TMM-Corp-Site-Icons-64TMM-Corp-Site-Icons-65TMM-Corp-Site-Icons-66TMM-Corp-Site-Icons-67TMM-Corp-Site-Icons-68TMM-Corp-Site-Icons-69TMM-Corp-Site-Icons-70TMM-Corp-Site-Icons-71TMM-Corp-Site-Icons-72