Antiviral effect of nicotinamide on enterovirus-infected human islets in vitro: effect on virus replication and chemokine secretion

Development of favipiravir dry powders for intranasal delivery: An integrated cocrystal and particle engineering approach via spray freeze drying

The therapeutic potential of pharmaceutical cocrystals in intranasal applications remains largely unexplored despite progressive advancements in cocrystal research. We present the application of spray freeze drying (SFD) in successful fabrication of a favipiravir-pyridinecarboxamide cocrystal nasal powder formulation for potential treatment of broad-spectrum antiviral infections. Preliminary screening via mechanochemistry revealed that favipiravir (FAV) can cocrystallize with isonicotinamide (INA), but not nicotinamide (NCT) and picolinamide (PIC) notwithstanding their structural similarity. The cocrystal formation was characterized by differential scanning calorimetry, Fourier-transform infrared spectroscopy, and unit cell determination through Rietveld refinement of powder X-ray analysis. FAV-INA crystalized in a monoclinic space group P21/c with a unit cell volume of 1223.54(3) Å3, accommodating one FAV molecule and one INA molecule in the asymmetric unit. The cocrystal was further reproduced as intranasal dry powders by SFD, of which the morphology, particle size, in vitro drug release, and nasal deposition were assessed. The non-porous flake shaped FAV-INA powders exhibited a mean particle size of 19.79 ± 2.61 μm, rendering its suitability for intranasal delivery. Compared with raw FAV, FAV-INA displayed a 3-fold higher cumulative fraction of drug permeated in Franz diffusion cells at 45 min (p = 0.001). Dose fraction of FAV-INA deposited in the nasal fraction of a customized 3D-printed nasal cast reached over 80 %, whereas the fine particle fraction remained below 6 % at a flow rate of 15 L/min, suggesting high nasal deposition whilst minimal lung deposition. FAV-INA was safe in RPMI 2650 nasal and SH-SY5Y neuroblastoma cells without any in vitro cytotoxicity observed. This study demonstrated that combining the merits of cocrystallization and particle engineering via SFD can propel the development of advanced dry powder formulations for intranasal drug delivery.

Development and Evaluation of Tacrolimus Loaded Nano-Transferosomes for Skin Targeting and Dermatitis Treatment

Tacrolimus (TRL) is used for the treatment of atopic dermatitis (AD) due to its T-cell stimulation effect. However, its significantly poor water solubility, low penetration and cytotoxicity have reduced its topical applications. Herein, tacrolimus loaded nano transfersomes (TRL-NTs) were prepared, followed by their incorporation into chitosan gel to prepare tacrolimus loaded nano transfersomal gel (TRL-NTsG). TEM analysis of the TRL-NTs was performed to check their morphology. DSC, XRD and FTIR analysis of the TRL-NTs were executed after lyophilization. Similarly, rheology, spreadability and deformability of the TRL-NTsG were investigated. In vitro release, ex vivo permeation and in vitro interaction of TRL-NTsG with keratinocytes and fibroblasts as well as their co-cultures were investigated along with their in vitro cell viability analysis. Moreover, in vivo skin deposition, ear thickness, histopathology and IgE level were also determined. Besides, 6 months stability study was also performed. Results demonstrated the uniformly distributed negatively charged nanovesicles with a mean particle size distribution of 163 nm and zeta potential of -27 mV. DSC and XRD exhibited the thermal stability and amorphous form of the drug, respectively. The TRL-NTsG showed excellent deformability, spreadability and rheological behavior. In vitro release studies exhibited an 8-fold better release of TRL from the TRL-NTsG. Similarly, 6-fold better permeation and stability of the TRL-NTsG with keratinocytes and fibroblasts as well as their co-cultures was observed. Furthermore, the ear thickness (0.6 mm) of the TRL-NTsG was found significantly reduced when compared with the untreated (1.7 mm) and TRL conventional gel treated mice (1.3 mm). The H&E staining showed no toxicity of the TRL-NTsG with significantly reduced IgE levels (120 ng/mL). The formulation was found stable for at least 6 months. These results suggested the efficacy of TRL in AD-induced animal models most importantly when incorporated in NTsG.

Drug Screening for Hepatitis A Virus (HAV): Nicotinamide Inhibits c-Jun Expression and HAV Replication

Hepatitis A virus (HAV) infection often causes acute hepatitis, which results in a case fatality rate of 0.2% and fulminant hepatitis in 0.5% of cases. However, no specific potent anti-HAV drug is available on the market to date. In the present study, we focused on inhibition of HAV internal ribosomal entry site (IRES)-mediated translation and investigated novel therapeutic drugs through drug repurposing by screening for inhibitors of HAV IRES-mediated translation and cell viability using a reporter assay and cell viability assay, respectively. The initial screening of 1,158 drugs resulted in 77 candidate drugs. Among them, nicotinamide significantly inhibited HAV HA11-1299 genotype IIIA replication in Huh7 cells. This promising drug also inhibited HAV HM175 genotype IB subgenomic replicon and HAV HA11-1299 genotype IIIA replication in a dose-dependent manner. In the present study, we found that nicotinamide inhibited the activation of activator protein 1 (AP-1) and that knockdown of c-Jun, which is one of the components of AP-1, inhibited HAV HM175 genotype IB IRES-mediated translation and HAV HA11-1299 genotype IIIA and HAV HM175 genotype IB replication. Taken together, the results showed that nicotinamide inhibited c-Jun, resulting in the suppression of HAV IRES-mediated translation and HAV replication, and therefore, it could be useful for the treatment of HAV infection. IMPORTANCE Drug screening methods targeting HAV IRES-mediated translation with reporter assays are attractive and useful for drug repurposing. Nicotinamide (vitamin B3, niacin) has been shown to effectively inhibit HAV replication. Transcription complex activator protein 1 (AP-1) plays an important role in the transcriptional regulation of cellular immunity or viral replication. The results of this study provide evidence that AP-1 is involved in HAV replication and plays a role in the HAV life cycle. In addition, nicotinamide was shown to suppress HAV replication partly by inhibiting AP-1 activity and HAV IRES-mediated translation. Nicotinamide may be useful for the control of acute HAV infection by inhibiting cellular AP-1 activity during HAV infection processes.

Type I interferon detection in autoimmune diseases: challenges and clinical applications

INTRODUCTION

Accumulating data highlights that the dysregulation of type I interferon (IFN) pathways plays a central role in the pathogenesis of several systemic and organ-specific autoimmune diseases. Advances in understanding the role of type I IFNs in these disorders can lead to targeted drug development as well as establishing potential disease biomarkers.

AREAS COVERED

Here, we summarize current knowledge regarding the role of type I IFNs in the major systemic, as well as organ-specific, autoimmune disorders, including prominent inflammatory CNS disorders like multiple sclerosis.

EXPERT OPINION

Type I IFN involvement and its clinical associations in a wide spectrum of autoimmune diseases represents a promising area for research aiming to unveil common pathogenetic pathways in systemic and organ-specific autoimmunity.

Type I interferons as key players in pancreatic β-cell dysfunction in type 1 diabetes

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by pancreatic islet inflammation (insulitis) and specific pancreatic β-cell destruction by an immune attack. Although the precise underlying mechanisms leading to the autoimmune assault remain poorly understood, it is well accepted that insulitis takes place in the context of a conflicting dialogue between pancreatic β-cells and the immune cells. Moreover, both host genetic background (i.e., candidate genes) and environmental factors (e.g., viral infections) contribute to this inadequate dialogue. Accumulating evidence indicates that type I interferons (IFNs), cytokines that are crucial for both innate and adaptive immune responses, act as key links between environmental and genetic risk factors in the development of T1D. This chapter summarizes some relevant pathways involved in β-cell dysfunction and death, and briefly reviews how enteroviral infections and genetic susceptibility can impact insulitis. Moreover, we present the current evidence showing that, in β-cells, type I IFN signaling pathway activation leads to several outcomes, such as long-lasting major histocompatibility complex (MHC) class I hyperexpression, endoplasmic reticulum (ER) stress, epigenetic changes, and induction of posttranscriptional as well as posttranslational modifications. MHC class I overexpression, when combined with ER stress and posttranscriptional/posttranslational modifications, might lead to sustained neoantigen presentation to immune system and β-cell apoptosis. This knowledge supports the concept that type I IFNs are implicated in the early stages of T1D pathogenesis. Finally, we highlight the promising therapeutic avenues for T1D treatment directed at type I IFN signaling pathway.

Interferon alpha: The key trigger of type 1 diabetes

IFNα is a cytokine essential to a vast array of immunologic processes. Its induction early in the innate immune response provides a priming mechanism that orchestrates numerous subsequent pathways in innate and adaptive immunity. Despite its beneficial effects in viral infections IFNα has been reported to be associated with several autoimmune diseases including autoimmune thyroid disease, systemic lupus erythematosus, rheumatoid arthritis, primary biliary cholangitis, and recently emerged as a major cytokine that triggers Type 1 Diabetes. In this review, we dissect the role of IFNα in T1D, focusing on the potential pathophysiological mechanisms involved. Evidence from human and mouse studies indicates that IFNα plays a key role in enhancing islet expression of HLA-I in patients with T1D, thereby increasing autoantigen presentation and beta cell activation of autoreactive cytotoxic CD8 T-lymphocytes. The binding of IFNα to its receptor induces the secretion of chemokines, attracting monocytes, T lymphocytes, and NK cells to the infected tissue triggering autoimmunity in susceptible individuals. Furthermore, IFNα impairs insulin production through the induction of endoplasmic reticulum stress as well as by impairing mitochondrial function. Due to its central role in the early phases of beta cell death, targeting IFNα and its pathways in genetically predisposed individuals may represent a potential novel therapeutic strategy in the very early stages of T1D.

Tacrolimus nanoparticles based on chitosan combined with nicotinamide: enhancing percutaneous delivery and treatment efficacy for atopic dermatitis and reducing dose

Background

Topical application of tacrolimus (FK506) was effective in the treatment of atopic dermatitis (AD); however, adverse effects frequently occurred with the increase of FK506 dose during long–term treatment.

Objective

The objective of this project was to develop a hybrid skin targeting system encapsulating FK506 based on nicotinamide (NIC) and chitosan nanoparticles (CS–NPs), ie, FK506–NIC–CS–NPs, which took advantages of both of NIC and CS–NPs to obtain the synergetic effects of percutaneous delivery and treatment efficacy enhancement along with dose reduction.

Methods

The formulation of FK506–NIC–CS–NPs was optimized and characterized. In vitro and in vivo skin permeation studies were performed. AD–like skin lesions were constructed with BALB/c mice by 1–chloro–2, 4–dinitrobenzene (DNCB)–induced, and FK506–NIC–CS–NPs containing different dose of FK506 were topically administered to treat AD–like skin lesions in comparison with Protopic.

Results

NIC was found to significantly increase the FK506 EE to 92.2% by CS–NPs. In comparison with commercial FK506 ointment (Protopic), in vitro and in vivo skin permeation studies demonstrated that NIC–CS–NPs system significantly enhanced FK506 permeation through and into the skin, and deposited more FK506 into the skin. The treatment efficacy on clinical symptoms, histological analysis, and molecular biology of the AD–mice demonstrated that NIC–CS–NPs with ~1/3 dose of FK506 of Protopic was superior to that of Protopic, and NIC–CS–NPs vehicle exhibited the adjuvant therapy and moderate anti–AD effects.

Conclusion

The system of NIC–CS–NPs enhances the permeability of FK506, plays an adjuvant role in anti-AD, reduces the dose of FK506 in treating AD, and is therefore a promising nanoscale system of FK506 for the effective treatment of AD.

Viral infections in type 1 diabetes mellitus--why the β cells?

Type 1 diabetes mellitus (T1DM) is caused by progressive autoimmune-mediated loss of pancreatic β-cell mass via apoptosis. The onset of T1DM depends on environmental factors that interact with predisposing genes to induce an autoimmune assault against β cells. Epidemiological, clinical and pathology studies in humans support viral infection--particularly by enteroviruses (for example, coxsackievirus)--as an environmental trigger for the development of T1DM. Many candidate genes for T1DM, such as MDA5, PTPN2 and TYK2, regulate antiviral responses in both β cells and the immune system. Cellular permissiveness to viral infection is modulated by innate antiviral responses that vary among different tissues or cell types. Some data indicate that pancreatic islet α cells trigger a more efficient antiviral response to infection with diabetogenic viruses than do β cells, and so are able to eradicate viral infections without undergoing apoptosis. This difference could account for the varying ability of islet-cell subtypes to clear viral infections and explain why chronically infected pancreatic β cells, but not α cells, are targeted by an autoimmune response and killed during the development of T1DM. These issues and attempts to target viral infection as a preventive therapy for T1DM are discussed in the present Review.

Enterovirus infection of human islets of Langerhans affects β-cell function resulting in disintegrated islets, decreased glucose stimulated insulin secretion and loss of Golgi structure

AIMS/HYPOTHESIS

In type 1 diabetes (T1D), most insulin-producing β cells are destroyed, but the trigger is unknown. One of the possible triggers is a virus infection and the aim of this study was to test if enterovirus infection affects glucose stimulated insulin secretion and the effect of virus replication on cellular macromolecules and organelles involved in insulin secretion.

METHODS

Isolated human islets were infected with different strains of coxsackievirus B (CVB) virus and the glucose-stimulated insulin release (GSIS) was measured in a dynamic perifusion system. Classical morphological electron microscopy, large-scale electron microscopy, so-called nanotomy, and immunohistochemistry were used to study to what extent virus-infected β cells contained insulin, and real-time PCR was used to analyze virus induced changes of islet specific genes.

RESULTS

In islets infected with CVB, GSIS was reduced in correlation with the degree of virus-induced islet disintegration. The expression of the gene encoding insulin was decreased in infected islets, whereas the expression of glucagon was not affected. Also, in islets that were somewhat disintegrated, there were uninfected β cells. Ultrastructural analysis revealed that virus particles and virus replication complexes were only present in β cells. There was a significant number of insulin granules remaining in the virus-infected β cells, despite decreased expression of insulin mRNA. In addition, no typical Golgi apparatus was detected in these cells. Exposure of islets to synthetic dsRNA potentiated glucose-stimulated insulin secretion.

CONCLUSIONS/INTERPRETATION

Glucose-stimulated insulin secretion; organelles involved in insulin secretion and gene expression were all affected by CVB replication in β cells.

Coxsackie-adenovirus receptor expression is enhanced in pancreas from patients with type 1 diabetes

OBJECTIVES

One of the theories connecting enterovirus (EV) infection of human islets with type 1 diabetes (T1D) is the development of a fertile field in the islets. This implies induction of appropriate proteins for the viral replication such as the coxsackie-adenovirus receptor (CAR). The aim of this study was to investigate to what extent CAR is expressed in human islets of Langerhans, and what conditions that would change the expression.

DESIGN

Immunohistochemistry for CAR was performed on paraffin-embedded pancreatic tissue from patients with T1D (n=9 recent onset T1D, n=4 long-standing T1D), islet autoantibody-positive individuals (n=14) and non-diabetic controls (n=24) individuals. The expression of CAR was also examined by reverse transcription PCR on microdissected islets (n=5), exocrine tissue (n=5) and on explanted islets infected with EV or exposed to chemokines produced by EV-infected islet cells.

RESULTS

An increased frequency of patients with T1D and autoantibody-positive individuals expressed CAR in the pancreas (p<0.039). CAR staining was detected more frequently in pancreatic islets from patients with T1D and autoantibody-positive subjects (15/27) compared with (6/24) non-diabetic controls (p<0.033). Also in explanted islets cultured in UV-treated culture medium from coxsackievirus B (CBV)-1-infected islets, the expression of the CAR gene was increased compared with controls. Laser microdissection of pancreatic tissue revealed that CAR expression was 10-fold higher in endocrine compared with exocrine cells of the pancreas. CAR was also expressed in explanted islets and the expression level decreased with time in culture. CBV-1 infection of explanted islets clearly decreased the expression of CAR (p<0.05). In contrast, infection with echovirus 6 did not affect the expression of CAR.

CONCLUSIONS

CAR is expressed in pancreatic islets of patients with T1D and the expression level of CAR is increased in explanted islets exposed to proinflammatory cytokines/chemokines produced by infected islets. T1D is associated with increased levels of certain chemokines/cytokines in the islets and this might be the mechanism behind the increased expression of CAR in TID islets.

Stereochemical Investigations of Diastereomeric N-[2-(Aryl)-5-methyl-4-oxo-1,3-thiazolidine-3-yl]-pyridine-3-carboxamides by Nuclear Magnetic Resonance Spectroscopy (1D and 2D)

Some new N-[2-(aryl)-5-methyl-4-oxo-1,3-thiazolidine-3-yl]-pyridine-3-carboxamides were synthesized and their structures were investigated by IR, NMR (1H, 13C, and 2D), and mass spectra. The presence of C-2 and C-5 stereogenic centers on the thiazolidinone ring resulted in diastereoisomeric pairs. The configurations of two stereogenic centers were assigned based upon 1H NMR analysis of coupling constants and 2D nuclear overhauser enhancement spectroscopy (NOESY) experiment. Resolution of the diastereoisomers was performed by high performance liquid chromatography (HPLC) using a chiral stationary phase.

Expression of human leukocyte antigen class I in endocrine and exocrine pancreatic tissue at onset of type 1 diabetes

The cause of type 1 diabetes remains unknown. To dissect the link between hyperexpression of human leukocyte antigen (HLA) class I on the islet cells, we examined its expression in subjects with recent-onset type 1 diabetes. IHC showed seemingly pronounced hyperexpression in subjects with recent-onset type 1 diabetes, as well as in some nondiabetic subjects. In all subjects, HLA class I expression on exocrine tissue was low. However, no difference in the level of HLA class I expression was found between islet and exocrine tissue using Western blot, flow cytometry, real-time quantitative PCR, or RNA sequencing analyses. Also, the level of HLA class I expression on the messenger level was not increased in islets from subjects with recent-onset type 1 diabetes compared with that in nondiabetic subjects. Consistently, the HLA class I specific enhanceosome (NLRC5) and related transcription factors, as well as interferons, were not enhanced in islets from recent-onset type 1 diabetic subjects. In conclusion, a discrepancy in HLA class I expression in islets assessed by IHC was observed compared with that using quantitative techniques showing similar expression of HLA class I in islets and exocrine tissue in subjects with recent-onset type 1 diabetes, nor could any differences be found between type 1 diabetic and nondiabetic subjects. Results presented provide important clues for a better understanding on how this complex disease develops.

Niacinamide - mechanisms of action and its topical use in dermatology

Niacinamide, an amide of vitamin B3 (niacin), is a hydrophilic endogenous substance. Its effects after epicutaneous application have long been described in the literature. Given a sufficient bioavailability, niacinamide has antipruritic, antimicrobial, vasoactive, photo-protective, sebostatic and lightening effects depending on its concentration. Within a complex metabolic system niacinamide controls the NFκB-mediated transcription of signalling molecules by inhibiting the nuclear poly (ADP-ribose) polymerase-1 (PARP-1). Niacinamide is a well-tolerated and safe substance often used in cosmetics. Clinical data for its therapeutic use in various dermatoses can increasingly be found in the literature. Although the existing data are not sufficient for a scientifically founded evaluation, it can be stated that the use of niacinamide in galenic preparations for epicutaneous application offers most interesting prospects.

Evaluation of the fidelity of immunolabelling obtained with clone 5D8/1, a monoclonal antibody directed against the enteroviral capsid protein, VP1, in human pancreas

AIMS/HYPOTHESIS

Enteroviral infection has been implicated in the development of islet autoimmunity in type 1 diabetes and enteroviral antigen expression has been detected by immunohistochemistry in the pancreatic beta cells of patients with recent-onset type 1 diabetes. However, the immunohistochemical evidence relies heavily on the use of a monoclonal antibody, clone 5D8/1, raised against an enteroviral capsid protein, VP1. Recent data suggest that the clone 5D8/1 may also recognise non-viral antigens; in particular, a component of the mitochondrial ATP synthase (ATP5B) and an isoform of creatine kinase (CKB). Therefore, we evaluated the fidelity of immunolabelling by clone 5D8/1 in the islets of patients with type 1 diabetes.

METHODS

Enteroviral VP1, CKB and ATP5B expression were analysed by western blotting, RT-PCR and immunocytochemistry in a range of cultured cell lines, isolated human islets and human tissue.

RESULTS

Clone 5D8/1 labelled CKB, but not ATP5B, on western blots performed under denaturing conditions. In cultured human cell lines, isolated human islets and pancreas sections from patients with type 1 diabetes, the immunolabelling of ATP5B, CKB and VP1 by 5D8/1 was readily distinguishable. Moreover, in a human tissue microarray displaying more than 80 different cells and tissues, only two (stomach and colon; both of which are potential sites of enterovirus infection) were immunopositive when stained with clone 5D8/1.

CONCLUSIONS/INTERPRETATION

When used under carefully optimised conditions, the immunolabelling pattern detected in sections of human pancreas with clone 5D8/1 did not reflect cross-reactivity with either ATP5B or CKB. Rather, 5D8/1 is likely to be representative of enteroviral antigen expression.

CXCR3, CXCL10 and type 1 diabetes

Type 1 diabetes (T1D) is due to antigen-specific assaults on the insulin producing pancreatic β-cells by diabetogenic T-helper (Th)1 cells. (C-X-C motif) ligand (CXCL)10, an interferon-γ inducible Th1 chemokine, and its receptor, (C-X-C motif) receptor (CXCR)3, have an important role in different autoimmune diseases. High circulating CXCL10 levels were detected in new onset T1D patients, in association with a Th1 autoimmune response. Furthermore β-cells produce CXCL10, under the influence of Th1 cytokines, that suppresses their proliferation. Viral β-cells infections induce cytokines and CXCL10 expression, inducing insulin-producing cell failure in T1D. CXCL10/CXCR3 system plays a critical role in the autoimmune process and in β-cells destruction in T1D. Blocking CXCL10 in new onset diabetes seems a possible approach for T1D treatment.

Enteroviruses and the pathogenesis of type 1 diabetes revisited: cross-reactivity of enterovirus capsid protein (VP1) antibodies with human mitochondrial proteins

Current or recent enteroviral infections show an association with type 1 diabetes. However, evidence for this has mainly been generated using a particular mouse monoclonal antibody (clone 5-D8/1) which binds the viral capsid protein VP1. Difficulty in confirming these findings using other independent methods has led to the concern that this might be artefactual. To address this, we examined the potential cross-reactivity of clone 5-D8/1 with normal islet proteins. Western blotting, two-dimensional gel electrophoresis, and mass spectrometry were used to identify human islet proteins bound by the clone 5-D8/1. We found a distinct reactivity with two mitochondrial proteins, creatine kinase B-type and ATP synthase beta subunit. Immunohistochemistry using the clone 5-D8/1 revealed a granular cytoplasmic staining pattern in mitochondria-rich cells, ie hepatocytes, ductal epithelial cells, vascular endothelial cells, skeletal muscle cells, and the neoplastic salivary gland oncocytoma cells, whereas connective tissue and infiltrating immune cells were negative. Staining on islets of Langerhans from subjects with recent-onset type 1 diabetes, but not on isolated human islets infected in vitro with enteroviruses, could be blocked after mixing the clone 5-D8/1 with the mitochondrial proteins. Collectively, our data show that the clone 5-D8/1 detects two human mitochondrial enzymes in addition to enteroviral VP1. The notion that the previously reported VP1 positivity in islets of recent-onset type 1 diabetes patients could reflect cross-reactivity to native islet proteins and not the presence of EV is supported by difficulties in demonstrating EV infection by independent techniques such as PCR or in situ hybridization. These findings call for revisiting the presence of enteroviruses in pancreatic islets of patients with type 1 diabetes.

Tropism Analysis of Two Coxsackie B5 Strains Reveals Virus Growth in Human Primary Pancreatic Islets but not in Exocrine Cell Clusters In Vitro

Human Enteroviruses (HEVs) have been implicated in human pancreatic diseases such as pancreatitis and type 1 diabetes (T1D). Human studies are sparse or inconclusive and our aim was to investigate the tropism of two strains of Coxsackie B virus 5 (CBV-5) in vitro to primary human pancreatic cells. Virus replication was measured with TCID50 titrations of aliquots of the culture medium at different time points post inoculation. The presence of virus particles or virus proteins within the pancreatic cells was studied with immunohistochemistry (IHC) and electron microscopy (EM). None of the strains replicated in the human exocrine cell clusters, in contrast, both strains replicated in the endocrine islets of Langerhans. Virus particles were found exclusively in the endocrine cells, often in close association with insulin granules. In conclusion, CBV-5 can replicate in human endocrine cells but not in human exocrine cells, thus they might not be the cause of pancreatitis in humans. The association of virus with insulin granules might reflect the use of these as replication scaffolds.

Nicotinamide, NAD(P)(H), and Methyl-Group Homeostasis Evolved and Became a Determinant of Ageing Diseases: Hypotheses and Lessons from Pellagra

Compartmentalized redox faults are common to ageing diseases. Dietary constituents are catabolized to NAD(H) donating electrons producing proton-based bioenergy in coevolved, cross-species and cross-organ networks. Nicotinamide and NAD deficiency from poor diet or high expenditure causes pellagra, an ageing and dementing disorder with lost robustness to infection and stress. Nicotinamide and stress induce Nicotinamide-N-methyltransferase (NNMT) improving choline retention but consume methyl groups. High NNMT activity is linked to Parkinson's, cancers, and diseases of affluence. Optimising nicotinamide and choline/methyl group availability is important for brain development and increased during our evolution raising metabolic and methylome ceilings through dietary/metabolic symbiotic means but strict energy constraints remain and life-history tradeoffs are the rule. An optimal energy, NAD and methyl group supply, avoiding hypo and hyper-vitaminoses nicotinamide and choline, is important to healthy ageing and avoids utilising double-edged symbionts or uncontrolled autophagy or reversions to fermentation reactions in inflammatory and cancerous tissue that all redistribute NAD(P)(H), but incur high allostatic costs.

Modulation of innate immunity in human pancreatic islets infected with enterovirus in vitro

Present knowledge of innate immunity in infected cells relies on studies of cell lines and animal models. In this study, primary human pancreatic islets of Langerhans were used to study virus-host interactions in a model of the possible induction of type 1 diabetes by enterovirus (EV). Human islets were infected with a strain of EV isolated at onset of type 1 diabetes, or exposed to synthetic dsRNA (poly(I:C)), used commonly to mimic viral infection. Induction of innate immunity and the effect of the female sex hormone 17β-estradiol, known to have cell-protective effects, on islet chemokine secretion were investigated. 17β-Estradiol reduced EV-but not poly(I:C)-induced IP-10/CXCL10 secretion from human islets, suggesting that separate signaling pathways of the innate immune response are triggered by EV and poly(I:C), respectively. Infection with EV increased the gene-expression of toll-like receptor 3, interferon-β, and the intracellular helicase MDA5, involved in antiviral innate immunity, multi-fold over time, whereas poly(I:C) increased the expression of these genes transiently. The induced expression pattern was similar in all donors, but the expression levels varied greatly. Pre-exposure to poly(I:C) blocked viral replication in islets from 56% of the donors. These data provide insight on the innate immune responses induced by EV in human islets, and show that this can be modulated by 17β-estradiol, and suggest an important difference between virus- and poly(I:C)-induced signaling.

N-[5-Methyl-2-(2-nitro-phen-yl)-4-oxo-1,3-thia-zolidin-3-yl]pyridine-3-carboxamide monohydrate

In the title compound, C₁₆H₁₄N₄O₄S·H₂O, the benzene and pyridine rings make a dihedral angle of 85.8 (1)°. Both enanti­omers of the chiral title compound are statistically disordered over the same position in the unit cell. The methyl and carbonyl group attached to the stereogenic center (C₅ of the thia­zolidine ring) were therefore refined with common site-occupation factors of 0.531 (9) and 0.469 (9), respectively, for each stereoisomer. In the crystal, inter­molecular N—H⋯O, O—H⋯O and O—H⋯N hydrogen bonds link the mol­ecules, forming a three-dimensional supra­molecular network. The crystal structure further shows π–π stacking inter­actions [centroid–centroid distance = 3.5063 (13) Å] between the pyridine rings.

N-[(2S)-2-(4-Bromo-phen-yl)-4-oxo-1,3-thia-zolidin-3-yl]pyridine-3-carboxamide

In the title compound, C₁₅H₁₂BrN₃O₂S, the dihedral angle between the pyridine and benzene rings is 73.17 (19)°. The five-membered 1,3-thia­zolidine ring has an envelope conformation, with the S atom displaced by 0.196 (1) Å from the mean plane of the four other ring atoms. An intra­molecular C—H⋯N inter­action occurs. The crystal structure is stabil­ized by inter­molecular N—H⋯O and C—H⋯O hydrogen bonds and C—H⋯π inter­actions. In addition, a weak π–π stacking inter­action is also observed between the 1,3-thia­zolidine and pyridine rings [centroid–centroid distance = 3.805 (2) Å].