Alterations in microbiome associated with acute pancreatitis.

PURPOSE OF REVIEW: This review evaluates the current knowledge of gut microbiome alterations in acute pancreatitis, including those that can increase acute pancreatitis risk or worsen disease severity, and the mechanisms of gut microbiome driven injury in acute pancreatitis. RECENT FINDINGS: Recent observational studies in humans showed the association of gut microbiome changes (decreased gut microbiome diversity, alterations in relative abundances of certain species, and association of unique species with functional pathways) with acute pancreatitis risk and severity. Furthermore, in-vivo studies highlighted the role of gut microbiome in the development and severity of acute pancreatitis using FMT models. The gut barrier integrity, immune cell homeostasis, and microbial metabolites appear to play key roles in acute pancreatitis risk and severity. SUMMARY: Large human cohort studies that assess gut microbiome profile, its metabolites and impact on acute pancreatitis risk and severity will be crucial for development of innovative prediction, prevention and treatment strategies.

Gestational Insulin Resistance Is Mediated by the Gut Microbiome-Indoleamine 2,3-Dioxygenase Axis.

BACKGROUND & AIMS: Normal gestation involves a reprogramming of the maternal gut microbiome (GM) that contributes to maternal metabolic changes by unclear mechanisms. This study aimed to understand the mechanistic underpinnings of the GM-maternal metabolism interaction. METHODS: The GM and plasma metabolome of CD1, NIH-Swiss, and C57 mice were analyzed with the use of 16S rRNA sequencing and untargeted liquid chromatography-mass spectrometry throughout gestation. Pharmacologic and genetic knockout mouse models were used to identify the role of indoleamine 2,3-dioxygenase (IDO1) in pregnancy-associated insulin resistance (IR). Involvement of gestational GM was studied with the use of fecal microbial transplants (FMTs). RESULTS: Significant variation in GM alpha diversity occurred throughout pregnancy. Enrichment in gut bacterial taxa was mouse strain and pregnancy time point specific, with the species enriched at gestation day 15/19 (G15/19), a point of heightened IR, being distinct from those enriched before or after pregnancy. Metabolomics revealed elevated plasma kynurenine at G15/19 in all 3 mouse strains. IDO1, the rate-limiting enzyme for kynurenine production, had increased intestinal expression at G15, which was associated with mild systemic and gut inflammation. Pharmacologic and genetic inhibition of IDO1 inhibited kynurenine levels and reversed pregnancy-associated IR. FMT revealed that IDO1 induction and local kynurenine level effects on IR derive from the GM in both mouse and human pregnancy. CONCLUSIONS: GM changes accompanying pregnancy shift IDO1-dependent tryptophan metabolism toward kynurenine production, intestinal inflammation, and gestational IR, a phenotype reversed by genetic deletion or inhibition of IDO1. (Gestational Gut Microbiome-IDO1 Axis Mediates Pregnancy Insulin Resistance; EMBL-ENA ID: PRJEB45047. MetaboLights ID: MTBLS3598).

Intestinal FFA3 mediates obesogenic effects in mice on a Western diet.

Free fatty acid receptor 3 (FFA3) is a recently-deorphanized G-protein-coupled receptor. Its ligands are short-chain fatty acids (SCFAs), which are key nutrients derived from the gut microbiome fermentation process that play diverse roles in the regulation of metabolic homeostasis and glycemic control. FFA3 is highly expressed within the intestine, where its role and its effects on physiology and metabolism are unclear. Previous in vivo studies involving this receptor have relied on global knockout mouse models, making it difficult to isolate intestine-specific roles of FFA3. To overcome this challenge, we generated an intestine-specific knockout mouse model for FFA3, Villin-Cre-FFA3 (Vil-FFA3). Model validation and general metabolic assessment of male mice fed a standard chow diet revealed no major congenital defects. Because dietary changes are known to alter gut microbial composition, and thereby SCFA production, an obesogenic challenge was performed on male Vil-FFA3 mice and their littermate controls to probe for a phenotype on a high-fat, high-sugar "Western diet" (WD) compared with a low-fat control diet (CD). Vil-FFA3 mice versus FFA3fl/fl controls on WD, but not CD, were protected from the development of diet-induced obesity and exhibited significantly less fat mass as well as smaller adipose depositions and adipocytes. Although overall glycemic control was unchanged in the WD-fed Vil-FFA3 group, fasted glucose levels trended lower. Intestinal inflammation was significantly reduced in the WD-fed Vil-FFA3 mice, supporting protection from obesogenic effects. Furthermore, we observed lower levels of gastric inhibitory protein (GIP) in the WD-fed Vil-FFA3 mice, which may contribute to phenotypic changes. Our findings suggest a novel role of intestinal FFA3 in promoting the metabolic consequences of a WD, including the development of obesity and inflammation. Moreover, these data support an intestine-specific role of FFA3 in whole body metabolic homeostasis and in the development of adiposity.NEW & NOTEWORTHY Here, we generated a novel intestine-specific knockout mouse model for FFA3 (Vil-FFA3) and performed a comprehensive metabolic characterization of mice in response to an obesogenic challenge. We found that Vil-FFA3 mice fed with a Western diet were largely protected from obesity, exhibiting significantly lower levels of fat mass, lower intestinal inflammation, and altered expression of intestinal incretin hormones. Results support an important role of intestinal FFA3 in contributing to metabolism and in the development of diet-induced obesity.

Free fatty acid receptor 3 differentially contributes to ß-cell compensation under high-fat diet and streptozotocin stress.

The free fatty acid receptor 3 (FFA3) is a nutrient sensor of gut microbiota-generated nutrients, the short-chain fatty acids. Previously, we have shown that FFA3 is expressed in ß-cells and inhibits islet insulin secretion ex vivo. Here, we determined the physiological relevance of the above observation by challenging wild-type (WT) and FFA3 knockout (KO) male mice with 1) hyperglycemia and monitoring insulin response via highly sensitive hyperglycemic clamps, 2) dietary high fat (HF), and 3) chemical-induced diabetes. As expected, FFA3 KO mice exhibited significantly higher insulin secretion and glucose infusion rate in hyperglycemic clamps. Predictably, under metabolic stress induced by HF-diet feeding, FFA3 KO mice exhibited less glucose intolerance compared with the WT mice. Moreover, similar islet architecture and ß-cell area in HF diet-fed FFA3 KO and WT mice was observed. Upon challenge with streptozotocin (STZ), FFA3 KO mice initially exhibited a tendency for an accelerated incidence of diabetes compared with the WT mice. However, this difference was not maintained. Similar glycemia and ß-cell mass loss was observed in both genotypes 10 days post-STZ challenge. Higher resistance to STZ-induced diabetes in WT mice could be due to higher basal islet autophagy. However, this difference was not protective because in response to STZ, similar autophagy induction was observed in both WT and FFA3 KO islets. These data demonstrate that FFA3 plays a role in modulating insulin secretion and ß-cell response to stressors. The ß-cell FFA3 and autophagy link warrant further research.

The short-chain fatty acid receptor, FFA2, contributes to gestational glucose homeostasis.

The structure of the human gastrointestinal microbiota can change during pregnancy, which may influence gestational metabolism; however, a mechanism of action remains unclear. Here we observed that in wild-type (WT) mice the relative abundance of Actinobacteria and Bacteroidetes increased during pregnancy. Along with these changes, short-chain fatty acids (SCFAs), which are mainly produced through gut microbiota fermentation, significantly changed in both the cecum and peripheral blood throughout gestation in these mice. SCFAs are recognized by G protein-coupled receptors (GPCRs) such as free fatty acid receptor-2 (FFA2), and we have previously demonstrated that the fatty acid receptor-2 gene (Ffar2) expression is higher in pancreatic islets during pregnancy. Using female Ffar2-/- mice, we explored the physiological relevance of signaling through this GPCR and found that Ffar2-deficient female mice developed fasting hyperglycemia and impaired glucose tolerance in the setting of impaired insulin secretion compared with WT mice during, but not before, pregnancy. Insulin tolerance tests were similar in Ffar2-/- and WT mice before and during pregnancy. Next, we examined the role of FFA2 in gestational ß-cell mass, observing that Ffar2-/- mice had diminished gestational expansion of ß-cells during pregnancy. Interestingly, mouse genotype had no significant impact on the composition of the gut microbiome, but did affect the observed SCFA profiles, suggesting a functional difference in the microbiota. Together, these results suggest a potential link between increased Ffar2 expression in islets and the alteration of circulating SCFA levels, possibly explaining how changes in the gut microbiome contribute to gestational glucose homeostasis.

Gene-environment interactions in heavy metal and pesticide carcinogenesis.

Cancer is a complex disease involving a sequence of gene-environment interactions. Lifestyle, genetics, dietary factors, and environmental pollutants can increase the risk of cancer. Gene-environment interactions have been studied by a candidate-gene approach focusing on metabolism, DNA repair, and apoptosis. Here, we review the influence of gene-environment interactions in carcinogenesis, with emphasis on heavy metal and pesticide exposures.

ß cell acetate production and release are negligible.

BACKGROUND: Studies suggest that short chain fatty acids (SCFAs), which are primarily produced from fermentation of fiber, regulate insulin secretion through free fatty acid receptors 2 and 3 (FFA2 and FFA3). As these are G-protein coupled receptors (GPCRs), they have potential therapeutic value as targets for treating type 2 diabetes (T2D). The exact mechanism by which these receptors regulate insulin secretion and other aspects of pancreatic ß cell function is unclear. It has been reported that glucose-dependent release of acetate from pancreatic ß cells negatively regulates glucose stimulated insulin secretion. While these data raise the possibility of acetate's potential autocrine action on these receptors, these findings have not been independently confirmed, and multiple concerns exist with this observation, particularly the lack of specificity and precision of the acetate detection methodology used. METHODS: Using Min6 cells and mouse islets, we assessed acetate and pyruvate production and secretion in response to different glucose concentrations, via liquid chromatography mass spectrometry. RESULTS: Using Min6 cells and mouse islets, we showed that both intracellular pyruvate and acetate increased with high glucose conditions; however, intracellular acetate level increased only slightly and exclusively in Min6 cells but not in the islets. Further, extracellular acetate levels were not affected by the concentration of glucose in the incubation medium of either Min6 cells or islets. CONCLUSIONS: Our findings do not substantiate the glucose-dependent release of acetate from pancreatic ß cells, and therefore, invalidate the possibility of an autocrine inhibitory effect on glucose stimulated insulin secretion.

Intestinal FFA2 promotes obesity by altering food intake in Western diet-fed mice.

Short-chain fatty acids (SCFAs) are key nutrients that play a diverse set of roles in physiological function, including regulating metabolic homeostasis. Generated through the fermentation of dietary fibers in the distal colon by the gut microbiome, SCFAs and their effects are partially mediated by their cognate receptors, including free fatty acid receptor 2 (FFA2). FFA2 is highly expressed in the intestinal epithelial cells, where its putative functions are controversial, with numerous in vivo studies relying on global knockout mouse models to characterize intestine-specific roles of the receptor. Here, we used the Villin-Cre mouse line to generate a novel, intestine-specific knockout mouse model for FFA2 (Vil-FFA2) to investigate receptor function within the intestine. Because dietary changes are known to affect the composition of the gut microbiome, and can thereby alter SCFA production, we performed an obesogenic challenge on male Vil-FFA2 mice and their littermate controls (FFA2-floxed, FFA2fl/fl) to identify physiological changes on a high-fat, high-sugar 'Western diet' (WD) compared to a low-fat control diet (CD). We found that the WD-fed Vil-FFA2 mice were transiently protected from the obesogenic effects of the WD and had lower fat mass and improved glucose homeostasis compared to the WD-fed FFA2fl/fl control group during the first half of the study. Additionally, major differences in respiratory exchange ratio and energy expenditure were observed in the WD-fed Vil-FFA2 mice, and food intake was found to be significantly reduced at multiple points in the study. Taken together, this study uncovers a novel role of intestinal FFA2 in mediating the development of obesity.

Cancer chemoprevention by polyphenols and their potential application as nanomedicine.

Today cancer is a leading cause of death among the developed countries. Its highly complex nature makes it difficult to understand as it entails multiple cellular physiological systems such as cell signaling and apoptosis. The biggest challenges faced by cancer chemoprevention/chemotherapy is maintaining drug circulation and avoiding multidrug resistance. Overall there is modest evidence regarding the protective effects of nutrients from supplements against a number of cancers. Numerous scientific literatures available advocate the use of polyphenols for chemoprevention. Some groups have also suggested use of combination of nutrients in cancer prevention. However, we have yet to obtain the desired results in the line of cancer chemotherapy research. Nanotechnology can play a pivotal role in cancer treatment and prevention. Moreover, nanoparticles can be modified in various ways to prolong circulation, enhance drug localization, increase drug efficacy, and potentially decrease the chances of multidrug resistance. In this communication, we will cover the use of various polyphenols and nutrients in cancer chemoprevention. The application of nanotechnology in this regard will also be included. In view of available reports on the potential of nanoparticles, we suggest their usage along with different combination of nutrients as cancer chemotherapeutic agents.

Ribosylation of bovine serum albumin induces ROS accumulation and cell death in cancer line (MCF-7).

Formation of advanced glycation end products (AGE) is crucially involved in the several pathophysiologies associated with ageing and diabetes, for example arthritis, atherosclerosis, chronic renal insufficiency, Alzheimer's disease, nephropathy, neuropathy, and cataracts. Because of devastating effects of AGE and the significance of bovine serum albumin (BSA) as a transport protein, this study was designed to investigate glycation-induced structural modifications in BSA and their functional consequences in breast cancer cell line (MCF-7). We incubated D-ribose with BSA and monitored formation of D-ribose-glycated BSA by observing changes in the intensity of fluorescence at 410 nm. NBT (nitro blue tetrazolium) assay was performed to confirm formation of keto-amine during glycation. Absorbance at 540 nm (fructosamine) increased markedly with time. Furthermore, intrinsic protein and 8-anilino-1-naphthalenesulfonate (ANS) fluorescence revealed marked conformational changes in BSA upon ribosylation. In addition, a fluorescence assay with thioflavin T (ThT) revealed a remarkable increase in fluorescence at 485 nm in the presence of glycated BSA. This suggests that glycation with D-ribose induced aggregation of BSA into amyloid-like deposits. Circular dichroism (CD) study of native and ribosylated BSA revealed molten globule formation in the glycation pathway of BSA. Functional consequences of ribosylated BSA on cancer cell line, MCF-7 was studied by MTT assay and ROS estimation. The results revealed cytotoxicity of ribosylated BSA on MCF-7 cells.

Different conformation of thiol protease inhibitor during amyloid formation: inhibition by curcumin and quercetin.

Cystatins are thiol proteinase inhibitors ubiquitously present in mammalian body and serve various important physiological functions. In the present study, we examined the effects of acid denaturation on newly identified thiol protease inhibitors from the lungs of Capra hircus (Goat) with a focus on protein conformational changes and amyloid fibril formation. Acid denaturation as studied by CD (Circular Dichroism) and fluorescence spectroscopy showed that purified inhibitor named GLC (Goat Lung Cystatin) populates three partly unfolded species, a native like state at pH 3.0, a partly unfolded intermediate at pH2.0, and unstructured unfolded state at pH 1.0, from each of which amyloid like fibrils grow as assessed by thioflavin T (ThT) spectroscopy. The result showed, native like structure formed at pH 3.0 is more responsive towards amyloid formation when compare to other conformation of proteins. Morphology of the protein species incubated for amyloid process was observed using transmission electron microscopy (TEM). Moreover, anti-fibrillogenic effects of curcumin and quercetin were analysed using ThT binding assay. Curcumin and quercetin produced a concentration dependent decline inThT fluorescence suggesting deaggregation of the fibrils. When added prior to amyloid fibril initiation 50 µM curcumin inhibited amyloid aggregation. However, more quercetin is needed to prevent the same extent of fibrillation. Implications for therapeutics in view of polyphenols as essential nutrients are suggested in lung diseases.

Benzo(a)pyrene induced structural and functional modifications in lung cystatin.

Cystatins are thiol proteinase inhibitors ubiquitously present in the mammalian body. They serve a protective function to regulate the activities of endogenous proteinases, which may cause uncontrolled proteolysis and damage. In the present study, the effect of benzo(a)pyrene [BaP] on lung cystatin was studied to explore the hazardous effects of environmental pollutant on structural and functional integrity of the protein. The basic binding interaction was studied by UV-absorption, FT-IR, and fluorescence spectroscopy. The enhancement of total protein fluorescence with a red shift of 5 nm suggests structural scratch of lung cystatin by benzo(a)pyrene. Further, ANS binding studies reaffirm the unfolding of the thiol protease inhibitor (GLC-I) after treating with benzo(a)pyrene. The results of FT-IR spectroscopy reflect perturbation of the secondary conformation (alpha-helix to ß-sheet) in goat lung cystatin on interaction with BaP. Finally, functional inactivation of cystatin on association with BaP was checked by its papain inhibitory activity. Benzo(a)pyrene (10 µM) caused complete inactivation of goat lung cystatin. Benzo(a)pyrene-induced loss of structure and function in the thiol protease inhibitor could provide a caution for lung injury caused by the pollutants and smokers.

Studies on the chemical modification of goat liver cystatin and the effect on its anti-papain inhibitory activity.

Goat liver cystatin was subjected to various chemical modifications in order to ascertain the amino acid residues responsible for its structural and functional integrity. Modification of tryptophan by HNBB led to the complete inactivation of the protein. The inactivation was also accompanied by the complete loss of tryptophan fluorescence at 340 nm. The reaction of liver cystatin with HNBB yielded a characteristic decrease in absorbance at 280 nm. Acetylation of the amino groups of liver cystatin was carried out in the presence of acetic anhydride. The acetylated cystatin showed a decrease in fluorescence intensity at 335 nm which could be attributed to the modification of tyrosine residue due to side reaction.

Conformational changes during amyloid fibril formation of pancreatic thiol proteinase inhibitor: effect of copper and zinc.

Pancreatic thiol proteinase inhibitor (PTPI), a variant of cystatin superfamily of cysteine protease inhibitors, has been isolated from pancreas of Capra hircus. In the present study, we examined the effects of acid denaturation and a co-solvent on PTPI with a focus on protein conformational changes and amyloid fibril formation. The results demonstrate that PTPI can form amyloid like fibrils. Acid denaturation as studied by CD and fluorescence spectroscopy showed that PTPI populates three partly unfolded species, a native like state at pH 3.0, a structured molten globule at pH 1.0 and partly unfolded species at pH 2.0, from each of which amyloid like fibrils grow as assessed by Thioflavin T (ThT) spectroscopy. Effect of trifluoroethanol (TFE) on acid induced states of PTPI was analyzed. TFE stabilized each of the three acid-induced intermediates at predenaturational concentrations (10%) and accelerated fibril formation. Morphology of the protein species at the beginning and end of reactions was observed using transmission electron microscopy. Solvent conditions were decisive for final fibril morphology. Biometals, Cu(2+) and Zn(2+) produced a concentration dependent decline in ThT fluorescence suggesting deaggregation of the fibrils. When added prior to amyloid fibril initiation 50 µM Cu(2+) or 10 µM Zn(2+) prevented any amyloid aggregation. Implications for therapeutics in view of Cu(2+) and Zn(2+) as essential micronutrients are suggested.

Aggregation and inactivation of pancreatic cystatin by riboflavin-derived singlet oxygen and flavin triplet state: polyphenols as preventive agents.

Caprine pancreatic thiol proteinase inhibitor (PTPI) a cystatin superfamily variant has high affinity for cysteine proteinases providing tight regulation of their proteolytic potential. Oxidative stress buildup in various pancreatic pathologies worsens the disease course often by disturbing the delicate balance between proteinases and their inhibitors. We aimed to study the effect of reactive oxygen species (ROS) on PTPI and to determine the potency of caffeic acid, curcumin and quercetin as agents against the inflicted damage. Fluorescence spectroscopy, polyacrylamide gel electrophoresis, and papain inhibitory assay revealed that photoilluminated riboflavin severely challenged the functional and structural integrity of the inhibitor. Three hundred and fifty micromolar affeic acid or quercetin prevented the damage. Curcumin, however, failed to reverse the changes completely. Conclusively, PTPI rendered dysfunctional by ROS may explain the increased necrotic damage to the host tissue. Also, dietary antioxidants can reverse the riboflavin-induced protein damage providing an economic and safe anti-ROS therapy.

The future treatment for type 1 diabetes: Pig islet- or stem cell-derived ß cells?

Replacement of ß cells is only a curative approach for type 1 diabetes (T1D) patients to avoid the threat of iatrogenic hypoglycemia. In this pursuit, islet allotransplantation under Edmonton's protocol emerged as a medical miracle to attain hypoglycemia-free insulin independence in T1D. Shortage of allo-islet donors and post-transplantation (post-tx) islet loss are still unmet hurdles for the widespread application of this therapeutic regimen. The long-term survival and effective insulin independence in preclinical studies have strongly suggested pig islets to cure overt hyperglycemia. Importantly, CRISPR-Cas9 technology is pursuing to develop "humanized" pig islets that could overcome the lifelong immunosuppression drug regimen. Lately, induced pluripotent stem cell (iPSC)-derived ß cell approaches are also gaining momentum and may hold promise to yield a significant supply of insulin-producing cells. Theoretically, personalized ß cells derived from a patient's iPSCs is one exciting approach, but ß cell-specific immunity in T1D recipients would still be a challenge. In this context, encapsulation studies on both pig islet as well as iPSC-ß cells were found promising and rendered long-term survival in mice. Oxygen tension and blood vessel growth within the capsules are a few of the hurdles that need to be addressed. In conclusion, challenges associated with both procedures, xenotransplantation (of pig-derived islets) and stem cell transplantation, are required to be cautiously resolved before their clinical application.

Effects of Sleep-Extend on glucose metabolism in women with a history of gestational diabetes: a pilot randomized trial.

OBJECTIVES: Women with a history of gestational diabetes (GDM) are at 7-fold increase in the risk of developing diabetes. Insufficient sleep has also been shown to increase diabetes risk. This study aimed to explore the feasibility of a sleep extension in women with a history of GDM and short sleep, and effects on glucose metabolism. METHODS: Women age 18-45 years with a history of GDM and actigraphy confirmed short sleep duration (<7 h/night) on weekdays were randomized at a ratio of 1 control (heathy living information) to 2 cases (6 weeks of "Sleep-Extend" intervention: use of a Fitbit, weekly digital content, and weekly coaching to increase sleep duration). An oral glucose tolerance test (OGTT), 7-day actigraphy recording, and questionnaires were obtained at baseline and 6 weeks. Mean differences between baseline and end-of-intervention parameters were compared using independent samples t-tests. RESULTS: Mean (SD) sleep duration increased within the Sleep-Extend group (n=9, +26.9 (42.5) min) but decreased within the controls (n=5, - 9.1 (20.4) min), a mean difference (MD) of 35.9 min (95% confidence interval (CI) - 8.6, 80.5). Fasting glucose increased, but less in Sleep-Extend vs. control groups (1.6 (9.4) vs 10.4 (8.2) mg/dL, MD - 8.8 mg/dL (95% CI - 19.8, 2.1), while 2-h glucose levels after an OGTT did not differ. Compared to controls, Sleep-Extend had decreased fatigue score (MD - 10.6, 95%CI - 20.7, - 0.6), and increased self-report physical activity (MD 5036 MET- minutes/week, 95%CI 343, 9729. Fitbit compliance and satisfaction in Sleep-Extend group was high. CONCLUSION: Sleep extension is feasible in women with a history of GDM, with benefits in fatigue and physical activity, and possibly glucose metabolism. These data support a larger study exploring benefits of sleep extension on glucose metabolism in these high-risk women. TRIAL REGISTRATION: ClinicalTrials.gov , NCT03638102 (8/20/2018).

The hexokinase "HKDC1" interaction with the mitochondria is essential for liver cancer progression.

Liver cancer (LC) is the fourth leading cause of death from cancer malignancies. Recently, a putative fifth hexokinase, hexokinase domain containing 1 (HKDC1), was shown to have significant overexpression in LC compared to healthy liver tissue. Using a combination of in vitro and in vivo tools, we examined the role of HKDC1 in LC development and progression. Importantly, HKDC1 ablation stops LC development and progression via its action at the mitochondria by promoting metabolic reprogramming and a shift of glucose flux away from the TCA cycle. HKDC1 ablation leads to mitochondrial dysfunction resulting in less cellular energy, which cannot be compensated by enhanced glucose uptake. Moreover, we show that the interaction of HKDC1 with the mitochondria is essential for its role in LC progression, and without this interaction, mitochondrial dysfunction occurs. As HKDC1 is highly expressed in LC cells, but only to a minimal degree in hepatocytes under normal conditions, targeting HKDC1, specifically its interaction with the mitochondria, may represent a highly selective approach to target cancer cells in LC.

FFAR from the Gut Microbiome Crowd: SCFA Receptors in T1D Pathology.

The gut microbiome has emerged as a novel determinant of type 1 diabetes (T1D), but the underlying mechanisms are unknown. In this context, major gut microbial metabolites, short-chain fatty acids (SCFAs), are considered to be an important link between the host and gut microbiome. We, along with other laboratories, have explored how SCFAs and their cognate receptors affect various metabolic conditions, including obesity, type 2 diabetes, and metabolic syndrome. Though gut microbiome and SCFA-level changes have been reported in T1D and in mouse models of the disease, the role of SCFA receptors in T1D remains under explored. In this review article, we will highlight the existing and possible roles of these receptors in T1D pathology. We conclude with a discussion of SCFA receptors as therapeutic targets for T1D, exploring an exciting new potential for novel treatments of glucometabolic disorders.

Cystatin like thiol proteinase inhibitor from pancreas of Capra hircus: purification and detailed biochemical characterization.

A thiol proteinase inhibitor from Capra hircus (goat) pancreas (PTPI) isolated by ammonium sulphate precipitation (20-80%) and gel filtration chromatography on Sephacryl S-100HR, with 20.4% yield and 500-fold purification, gave molecular mass of 44 kDa determined by its electrophoretic and gel filtration behavior, respectively. The stokes radius, diffusion and sedimentation coefficients of PTPI were 27.3 A, 7.87 x 10(-7) cm(2) s(-1) and 3.83 s, respectively. It was stable in pH range 3-10 and up to 70 degrees C (critical temperature, E (a) = 21 kJ mol(-1)). Kinetic analysis revealed reversible and competitive mode of inhibition with PTPI showing the highest inhibitory efficiency against papain (K ( i ) = 5.88 nM). The partial amino acid sequence analysis showed that it shared good homology with bovine parotid and skin cystatin C. PTPI possessed 17.18% alpha helical content assessed by CD spectroscopy. The hydropathy plot of first 24 residues suggested that most amino acids of this stretch might be in the hydrophobic core of the protein.