Caspase-3-dependent beta-cell apoptosis in the initiation of autoimmune diabetes mellitus

Insights on the role of anti-inflammatory and immunosuppressive agents in the amelioration of diabetes

Diabetes is a major health problem worldwide. It is a chronic metabolic disorder that produces overt hyperglycemic condition that occurs either when the pancreas does not produce enough insulin due to excessive destruction of pancreatic β-cells (type 1 diabetes) or due to development of insulin resistance (type 2 diabetes). An autoimmune condition known as type 1 diabetes (T1D) results in the targeted immune death of β-cells that produce insulin. The only available treatment for T1D at the moment is the lifelong use of insulin. Multiple islet autoantibody positivity is used to diagnose T1D. There are four standard autoantibodies observed whose presence shows the development of T1D: antibodies against insulin, glutamic acid decarboxylase (GAD65), zinc T8 transporter (ZnT8), and tyrosine phosphatase-like protein (ICA512). In type 2 diabetes (T2D), an inflammatory response precipitates as a consequence of the immune response to high blood glucose level along with the presence of inflammation mediators produced by macrophages and adipocytes in fat tissue. The slow and chronic inflammatory condition of adipose tissue produces insulin resistance leading to increased stress on pancreatic β-cells to produce more insulin to compensate for the insulin resistance. Thus, this stress condition exacerbates the apoptosis of β-cells leading to insufficient production of insulin, resulting in hyperglycemia which signifies late stage T2D. Therefore, the therapeutic utilization of immunosuppressive agents may be a better alternative over the use of insulin and oral hypoglycemic agents for the treatment of T1D and T2D, respectively. This review enlightens the immune intervention for the prevention and amelioration of T1D and T2D in humans with main focus on the antigen-specific immune suppressive therapy.

Exploring the mechanism of active components from ginseng to manage diabetes mellitus based on network pharmacology and molecular docking

A large body of literature has shown that ginseng had a role in diabetes mellitus management. Ginsenosides are the main active components of ginseng. But what ginsenosides can manage in diabetic are not systematic. The targets of these ginsenosides are still incomplete. Our aim was to identify which ginsenosides can manage diabetes mellitus through network pharmacology and molecular docking. To identify the targets of these ginsenosides. In this work, we retrieved and screened ginsenosides and corresponding diabetes mellitus targets across multiple databases. PPI networks of the genes were constructed using STRING, and the core targets were screened out through topological analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses were performed by using the R language. Finally, molecular docking was performed after bioinformatics analysis for verification. Our research results showed that 28 ginsenosides in ginseng might be against diabetes mellitus by modulating related proteins such as VEGFA, Caspase 3, and TNF-α. Among the 28 ginsenosides, 20(R)-Protopanaxatriol, 20(R)-Protopanaxadiol, and Ginsenoside Rg1 might play a significant role. Kyoto Encyclopedia of Genes and Genomes and Gene Ontology enrichment analysis showed that the management of diabetes mellitus by ginsenosides may be related to the positive regulation of reactive oxygen metabolic processes, associated with the insulin signaling pathway, TNF signaling pathway, and AMPK signaling pathway. Molecular docking results and molecular dynamics simulation showed that most ginsenosides could stably bind to the core target, mainly hydrogen bonding and hydrophobic bond. This study suggests the management of ginseng on diabetes mellitus. We believe that our results can contribute to the systematic study of the mechanism of ginsenosides for the management of diabetes mellitus. At the same time, it can provide a theoretical basis for subsequent studies on the management of ginsenosides in diabetes mellitus.

In Vivo Evaluation of Nanoemulsion Formulations for Metformin and Repaglinide Alone and Combination

Repaglinide and Metformin are used to treat Type 2 diabetes. Repaglinide with poor water solubility has relatively low oral bioavailability (56%) and undergoes hepatic first-pass metabolism. The oral bioavailability of metformin HCl is also low (about 50-60%). The purpose of this study was to prepare nanoemulsion formulations containing metformin HCl or repaglinide alone or in combination and characterize them in vitro and in vivo. Nanoemulsion formulations containing metformin HCl and/or repaglinide were successfully prepared and in vitro characterized. In addition, in vivo efficacy of nanoemulsion formulations was evaluated in a streptozotocin-nicotinamide-induced diabetic rat model. Biochemical, histopathological, and immunohistochemical evaluations were also performed. The mean droplet size and zeta potential values of nanoemulsion formulations were in the range of 110.15±2.64-120.23±2.16 nm and -21.95 - -24.33 mV, respectively. The percent entrapment efficiency values of nanoemulsion formulations were in the range of 93.600%-96.152%. All nanoemulsion formulations had a PDI of ≤0.223. A statistically significant decrease was observed in the blood glucose values of the diabetic rats treated with nanoemulsion formulations containing active substance/substances, compared to diabetic rats (control) (p<0.05). Nanoemulsion formulations (especially nanoemulsion containing metformin HCl and repaglinide combination) have a better antidiabetic activity and are more effective in reducing oxidative stress caused by diabetes.

Pancreatic Pathological Changes in Murine Toxoplasmosis and Possible Association with Diabetes Mellitus

BACKGROUND

Previous studies have reported involvement of Toxoplasma gondii (T. gondii) infections in the pathogenesis of some autoimmune diseases, such as polymyositis, rheumatoid arthritis, autoimmune thyroiditis, and Crohn's disease. However, data on the association between T. gondii infections and Type 1 diabetes mellitus (T1DM) are still controversial. Therefore, in the present study, we aimed to investigate the pancreatic pathological changes in mouse models with acute and chronic toxoplasmosis and their association with T1DM.

MATERIALS AND METHODS

Three groups (10 mice each) of male Swiss Albino mice were used. One group of mice was left uninfected, whereas the second and third groups were infected with the acute virulent T. gondii RH strain and the chronic less virulent Me49 T. gondii strain, respectively. T. gondii-induced pancreatic pathological changes were evaluated by histopathological examination of pancreatic tissues. Moreover, the expression of insulin, levels of caspase-3, and the pancreatic infiltration of CD8⁺ T cells were evaluated using immunohistochemical staining.

RESULTS

Pancreatic tissues of T. gondii-infected animals showed significant pathological alterations and variable degrees of insulitis. Mice with acute toxoplasmosis exhibited marked enlargement and reduced numbers of islets of Langerhans. However, mice with chronic toxoplasmosis showed considerable reduction in size and number of islets of Langerhans. Moreover, insulin staining revealed significant reduction in β cell numbers, whereas caspase-3 staining showed induced apoptosis in islets of Langerhans of acute toxoplasmosis and chronic toxoplasmosis mice compared to uninfected mice. We detected infiltration of CD8⁺ T cells only in islets of Langerhans of mice with chronic toxoplasmosis.

CONCLUSIONS

Acute and chronic toxoplasmosis mice displayed marked pancreatic pathological changes with reduced numbers of islets of Langerhans and insulin-producing-β cells. Since damage of β cells of islets of Langerhans is associated with the development of T1DM, our findings may support a link between T. gondii infections and the development of T1DM.

Dysregulation of Mir-193B and Mir-376A as a Biomarker of Prediabetes in Offspring of Gestational Diabetic Mice

Gestational diabetes mellitus (GDM) is a type of diabetes initiated during pregnancy and is characterized by maternal hyperglycemia that induces complications in mothers and children. In the current study, we used a GDM mouse model (through i.p. injection of a single dose of streptozocin, STZ, 60 mg/kg/bw) to investigate the biochemical and immunological changes in the blood and brain of diabetic mothers and their offspring relative to their appropriate controls. In addition, we estimated the expression levels of a set of microRNAs (miRNAs) to link between the dysregulation in the levels of miRNAs and the exposure to oxidative stress during embryonic development, as well as metabolic changes that occur after birth and during puberty in offspring (5-weeks-old). At the biochemical level, newborn pups appeared mostly to suffer from the same oxidative stress conditions of their mothers as shown by the significant increase in nitric oxide (NO) and malondialdehyde (MDA) in blood and brain of diabetic mothers and their pups. However, the 5-week-old offspring showed a significant increase in proinflammatory cytokines, IL-1β, IL-6, and TNF-α, and based on their blood glucose levels, could be considered as prediabetic (with glucose mean value of 165 mg/dl). In the meantime, the tested miRNAs, especially miR-15b, miR-146a, and miR-138 showed mostly similar expression levels in diabetic mothers and newborn pups. In this regard, miR-15a and -15b, miR-146a, and miR-138 are downregulated in diabetic mothers and their newborn pups relative to their appropriate controls. However, in offspring of diabetic mothers at puberty age, these miRNAs displayed different expression levels relative to mothers and control offspring. Interestingly, miR-193 and miR-763 expression levels were significantly lower in diabetic mothers but upregulated in their 5-week-old offspring, suggesting that miR-193 and miR-763 could be used as biomarkers to differentiate between prediabetes and diabetes.

Transient B-cell depletion and regulatory T-cells mediation in combination with adenovirus mediated IGF-1 prevents and reverses autoimmune diabetes in NOD mice

Type 1 diabetes (T1D) is one of the T cells mediated autoimmune diseases, although B cells also play an important role in the development. Both T cell and B cell targeted immunotherapies exhibited efficacies in preventing and reversing the T1D. Current study was performed to investigate the protective effects of anti-CD20/CD3 bi-specific antibody (bsAb) in combination with adenovirus mediated mouse insulin-like growth factor 1 (Adv-mIGF-1) gene on T1D in non-obese diabetes (NOD) mice. To simultaneously restore the proportion of Th cells and block the interaction of B cells as well as mediate T cell populations, the NOD model mice were randomly assigned to four groups received the saline, anti-CD20/CD3 bsAb and Adv-mIGF-1 gene alone or combination, respectively. After 16-consecutive weeks intervention, the ELISA, RT-PCR, western blot and histopathological analysis were performed to assess the pancreatic tissues and serum samples to evaluate the treatment effects. Chronic treatment of combination therapy improved T1D morbidity by improving the compartment and function of the CD4⁺Foxp3⁺ Tregs, reversing the secretion of insulin, controlling the blood glucose levels (BGLs) and alleviating insulitis as well as cell apoptosis in the NOD model mice. Moreover, current combination therapy also accelerated the proliferation and differentiation of pancreatic β cells via suppressing the apoptosis-related factors, including caspase-3, caspase-8 and Fas, and activating the Bcl-2-related anti-apoptotic pathway. Furthermore, the cytokeratin-19 (CK-19) and pancreatic duodenal homoplasmic box-1 (PDX-1), as two important stem cell markers of pancreas were both significantly improved by treatment of combination therapy. On conclusions, chronic treatment of anti-CD20/CD3 bsAb in combination with Adv-mIGF-1 gene exerts synergistic protection on T1D in the NOD mice.

∆nFGF1 Protects β-Cells against High Glucose-Induced Apoptosis via the AMPK/SIRT1/PGC-1α Axis

Long-term exposure to high glucose leads to β-cell dysfunction and death. Fibroblast growth factor 1 (FGF1) has emerged as a promising diabetes treatment, but its pharmaceutical role and mechanism against glucolipotoxicity-induced β-cell dysfunction remain uncharacterized. Wild-type FGF1 (FGF1^WT) may exhibit in vivo mitogenicity, but deletion of N-terminal residues 1-27 gives a nonmitogenic variant, ∆nFGF1, that does not promote cell proliferation and still retains the metabolic activity of FGF1^WT. To investigate the roles of ∆nFGF1 on glucose regulation and potential islet β-cell dysfunction, db/db mice were used as a model of type 2 diabetes. The results showed that insulin secretion and apoptosis of islet β-cells were dramatically improved in ∆nFGF1-treated db/db mice. To further test the effects of ∆nFGF1 treatment, pancreatic β-cell (MIN6) cells were exposed to a mixture of palmitic acid (PA) and high glucose (HG) to mimic glucolipotoxic conditions in vitro. Treatment with ∆nFGF1 significantly inhibited glucolipotoxicity-induced apoptosis. Mechanistically, ∆nFGF1 exerts a protective effect on β-cells via activation of the AMPK/SIRT1/PGC-1α signaling pathway. These findings demonstrate that ∆nFGF1 protects pancreatic β-cells against glucolipotoxicity-induced dysfunction and apoptosis.

NAG-1/GDF15 protects against streptozotocin-induced type 1 diabetes by inhibiting apoptosis, preserving beta-cell function, and suppressing inflammation in pancreatic islets

The loss of functional insulin-producing β-cells is a hallmark of type 1 diabetes mellitus (T1DM). Previously, we reported that the non-steroidal anti-inflammatory drug activated gene-1, or growth differentiation factor-15 (NAG-1/GDF15) inhibits obesity and improves insulin sensitivity in both genetic and dietary-induced obese mice. However, the regulatory role of NAG-1/GDF15 in the structure and function of β-cells and the prevention of T1DM is largely unknown. In the current study, we reported that NAG-1/GDF15 transgenic (Tg) mice are resistant to diabetogenesis induced by multiple low-dose streptozotocin (MLD-STZ) treatment. NAG-1/GDF15 overexpression significantly reduced diabetes incidence, alleviated symptoms of T1DM, and improved MLD-STZ-induced glucose intolerance and insulin resistance. Both the mass and function of pancreatic β cells were preserved in the NAG-1/GDF15 Tg mice as evidenced by significantly increased islet area and insulin production. The mechanistic study revealed that NAG-1/GDF15 significantly inhibited STZ-induced apoptosis and preserved the reduction of proliferation in the islets of the Tg mice as compared to the wild-type (WT) mice upon MLD-STZ treatment. Additionally, NAG-1/GDF15 significantly reduced both the serum and islet levels of the inflammatory cytokines (IL-1β, IL-6, and TNFα), and reduced the expression of NF-κB expression and immune cells infiltration in the islets. Collectively, these results indicate that NAG-1/GDF15 is effective in improving STZ-induced glucose intolerance, probably was mediated via suppressing inflammation, inhibiting apoptosis, and preserving β-cell mass and function.

Cadmium inhibits signal transducer and activator of transcription 6 leading to pancreatic β cell apoptosis

The toxic heavy metal cadmium has been proven to cause pancreatic dysfunction and lead to the development of DM. However, the underlying mechanisms have not been completely elucidated. Here, we investigated the effects of cadmium on the pancreatic β cell line MIN6 and explored the underlying mechanisms. The Cell Counting Kit-8 (CCK8) assay and flow cytometry were used to determine cell viability and apoptosis in MIN6 cells. The expression levels of signal transducer and activator of transcription 6 (STAT6) were assessed by western blotting. We further assessed the effects of cadmium on the function of pancreatic β cells under high glucose levels using enzyme-linked immunosorbent assay (ELISA) and western blotting. Insulin secretion and expression were decreased by cadmium in MIN6 cells. In addition, cadmium suppressed cell viability and promoted apoptosis of MIN6 cells, downregulated insulin secretion and genesis of MIN6 cells under high glucose conditions, while inhibiting STAT6. Furthermore, after treatment with IL-4, the activator of STAT6, the MIN6 cell viability suppression and apoptosis promotion effect caused by cadmium were blocked. In conclusion, cadmium inhibits pancreatic β cell MIN6 growth by regulating the activation of STAT6. Our findings reveal a new mechanism of cadmium toxicity in pancreatic β cells.

Expression of Caspase-3 in Circulating Innate Lymphoid Cells Subtypes Is Altered by Treatment with Metformin and Fluvastatin in High-Fat Diet Fed C57BL/6 Mice

The current study aimed to determine the expression levels of caspase-3 in circulating innate lymphoid cell subtypes (ILCs) in a high-fat diet (HFD)-induced prediabetes mouse model. Another critical point was to assess the therapeutic effects of metformin and fluvastatin in modulating caspase-3 activation in ILCs within these HFD-fed mice. Prominent results showed that mice exposed to HFD for 14 weeks displayed impaired glucose tolerance that was accompanied by elevated levels of low-density lipoprotein cholesterol (LDL-c) and altered haematological profile as characterised by significantly increased concentrations of red blood cell count, white cell count and lymphocytes when compared to those fed a low-fat diet (LFD). Moreover, the expression of caspase-3 in ILC1 and ILC3 was significantly increased in the HFD groups in comparison to the LFD-fed group. Notably, six-week treatment with metformin and fluvastatin reduced the caspase-3 activation in ILC subtypes. The reduced caspase-3 activation in ILC1 was inversely associated with HDL-c levels following metformin treatment. Interestingly, the reduced caspase-3 activation in ILC3 was associated with lower total cholesterol following fluvastatin treatment in these HFD-fed mice. However, there were no differences in activation of caspase-3 on ILC2 or any association between caspase-3 activation and changes in body weight or fasting blood glucose. Thus, while HFD-feeding clearly modulates ILCs, potentially leading to pro-apoptotic mechanisms, metformin and fluvastatin may play a major role in protecting against such metabolic disturbances.

BH3-Only Proteins Noxa and Puma Are Key Regulators of Induced Apoptosis

Apoptosis is an evolutionarily conserved and tightly regulated cell death pathway. Physiological cell death is important for maintaining homeostasis and optimal biological conditions by continuous elimination of undesired or superfluous cells. The BH3-only pro-apoptotic members are strong inducers of apoptosis. The pro-apoptotic BH3-only protein Noxa activates multiple death pathways by inhibiting the anti-apoptotic Bcl-2 family protein, Mcl-1, and other protein members leading to Bax and Bak activation and MOMP. On the other hand, Puma is induced by p53-dependent and p53-independent apoptotic stimuli in several cancer cell lines. Moreover, this protein is involved in several physiological and pathological processes, such as immunity, cancer, and neurodegenerative diseases. Future heat shock research could disclose the effect of hyperthermia on both Noxa and BH3-only proteins. This suggests post-transcriptional mechanisms controlling the translation of both Puma and Noxa mRNA in heat-shocked cells. This study was also the chance to recapitulate the different reactional mechanisms investigated for caspases.

Hypophosphorylated pRb knock-in mice exhibit hallmarks of aging and vitamin C-preventable diabetes

Despite extensive analysis of pRB phosphorylation in vitro, how this modification influences development and homeostasis in vivo is unclear. Here, we show that homozygous Rb^∆K4 and Rb^∆K7 knock‐in mice, in which either four or all seven phosphorylation sites in the C‐terminal region of pRb, respectively, have been abolished by Ser/Thr‐to‐Ala substitutions, undergo normal embryogenesis and early development, notwithstanding suppressed phosphorylation of additional upstream sites. Whereas Rb^∆K4 mice exhibit telomere attrition but no other abnormalities, Rb^∆K7 mice are smaller and display additional hallmarks of premature aging including infertility, kyphosis, and diabetes, indicating an accumulative effect of blocking pRb phosphorylation. Diabetes in Rb^∆K7 mice is insulin‐sensitive and associated with failure of quiescent pancreatic β‐cells to re‐enter the cell cycle in response to mitogens, resulting in induction of DNA damage response (DDR), senescence‐associated secretory phenotype (SASP), and reduced pancreatic islet mass and circulating insulin level. Pre‐treatment with the epigenetic regulator vitamin C reduces DDR, increases cell cycle re‐entry, improves islet morphology, and attenuates diabetes. These results have direct implications for cell cycle regulation, CDK‐inhibitor therapeutics, diabetes, and longevity.

Elucidate multidimensionality of type 1 diabetes mellitus heterogeneity by multifaceted information

Type 1 diabetes (T1D) is an autoimmune disease. Different factors, including genetics and viruses may contribute to T1D, but the causes of T1D are not fully known, and there is currently no cure. The advent of high-throughput technologies has revolutionized the field of medicine and biology, and analysis of multi-source data along with clinical information has brought a better understanding of the mechanisms behind disease pathogenesis. The aim of this work was the development of a data repository linking clinical information and interactome studies in T1D. To address this goal, we analyzed the electronic health records and online databases of genes, proteins, miRNAs, and pathways to have a global view of T1D. There were common comorbid diseases such as anemia, hypertension, vitreous diseases, renal diseases, and atherosclerosis in the phenotypic disease networks. In the protein-protein interaction network, CASP3 and TNF were date-hub proteins involved in several pathways. Moreover, CTNNB1, IGF1R, and STAT3 were hub proteins, whereas miR-155-5p, miR-34a-5p, miR-23-3p, and miR-20a-5p were hub miRNAs in the gene-miRNA interaction network. Multiple levels of information including genetic, protein, miRNA and clinical data resulted in multiple results, which suggests the complementarity of multiple sources. With the integration of multifaceted information, it will shed light on the mechanisms underlying T1D; the provided data and repository has utility in understanding phenotypic disease networks for the potential development of comorbidities in T1D patients as well as the clues for further research on T1D comorbidities.

In silico analysis of novel dipeptidyl peptidase-IV inhibitory peptides released from Macadamia integrifolia antimicrobial protein 2 (MiAMP2) and the possible pathways involved in diabetes protection

The aim of the present study was to screen novel dipeptidyl peptidase IV (DPP-IV) inhibitory peptides from Macadamia integrifolia antimicrobial protein 2 (MiAMP2) and evaluate the potential antidiabetic targets and involved signaling pathways using in silico approaches. In silico digestion of MiAMP2 with pepsin, trypsin and chymotrypsin was performed with ExPASy PeptideCutter and the generated peptides were subjected to BIOPEP-UWM, iDrug, INNOVAGEN and Autodock Vina for further analyses. Six novel peptides EQVR, EQVK, AESE, EEDNK, EECK, and EVEE were predicted to possess good DPP-IV inhibitory potentials, water solubility, and absorption, distribution, metabolism, excretion, and toxicity properties. Molecular dynamic simulation and molecular docking displayed that AESE was the most potent DPP-IV inhibitory peptide and can bind with the active sites of DPP-IV through hydrogen bonding and van der Waals forces. The potential antidiabetic targets of AESE were retrieved from SwissTargetPrediction and GeneCards databases. Protein-protein interaction analysis identified BIRC2, CASP3, MMP7 and BIRC3 to be the hub targets. Moreover, the KEGG pathway enrichment analysis showed that AESE prevented diabetes through the apoptosis and TNF signaling pathways. These results will provide new insights into utilization of MiAMP2 as functional food ingredients for the prevention and treatment of diabetes.

Explore the active ingredients and mechanisms in Musa basjoo pseudostem juice against diabetes based on animal experiment, gas chromatography-mass spectrometer and network pharmacology

BACKGROUND

Musa basjoo pseudostem juice (MBSJ) is a well-known Chinese medicine, and Miao people use MBSJ to treat diabetes. In this work, the active ingredients and molecular mechanism of MBSJ against diabetes were explored.

METHODS

Anti-diabetic activity of MBSJ was evaluated using diabetic rats, and then the ingredients in the small-polar parts of MBSJ were analyzed by gas chromatography-mass spectrometer (GC-MS). Targets were obtained from several databases to develop the "ingredient-target-disease" network by Cytoscape. A collaborative analysis was carried out using the tools in Cytoscape and R packages, and molecular docking was also performed.

RESULTS

MBSJ improved the oral glucose tolerance and insulin tolerance, and reduced fasting blood glucose, glycosylated hemoglobin, total cholesterol, triglyceride, and low-density lipoprotein levels in the serum of diabetic rats. 13 potential compounds were identified by GC-MS for subsequent analysis, including Dibutyl phthalate, Oleamide, Stigmasterol, Stigmast-4-en-3-one, etc. The anti-diabetic effect of MBSJ was related to multiple signaling pathways, including Neuroactive ligand-receptor interaction, Phospholipase D signaling pathway, Endocrine resistance, Rap1 signaling pathway, EGFR tyrosine kinase inhibitor resistance, etc. Molecular docking at least partially verified the screening results of network pharmacology.

CONCLUSION

MBSJ had good anti-diabetic activity. The small-polar parts of MBSJ were rich in anti-diabetic active ingredients. Furthermore, the analysis results showed that the anti-diabetic effect of the small-polar parts of MBSJ may be the result of multiple components, multiple targets, and multiple pathways. The current research results can provide important support for studying the active ingredients and exploring the underlying mechanism of MBSJ against diabetes.

Combined therapy of adenovirus vector mediated IGF-1 gene with anti-CD20 mAbs exerts potential beneficial role on type 1 diabetes in nonobese diabetic mice

AIMS

To assess the protective effects of combined treatment with anti-CD20 monoclonal antibody (mAb) and adenovirus mediated mouse insulin-like growth factor 1 (Adv-mIGF-1) gene on type 1 diabetes (T1D) in nonobese diabetic (NOD) mice at early stage.

METHODS

To simultaneously restore the proportion of Th cells and block the interaction of B cells, NOD model mice were assigned to four groups which received PBS, Adv-mIGF-1 gene and anti-CD20 mAbs alone or combination, respectively. After 16 weeks of therapeutic intervention, blood samples and pancreatic tissues of mice were measured via the methods of ELISA, RT-PCR, western blotting, H&E staining, TUNEL and immunohistochemistry assays.

KEY FINDINGS

Chronic combination intervention with Adv-mIGF-1 gene and anti-CD20 mAbs reduced the T1D-related morbidity, promoted the secretion of insulin, controlled the blood glucose levels (BGLs) and alleviated insulitis of experimental mice. In addition, current combination intervention also protected the pancreatic β cells via suppressing the expression of Fas and TNF-α, inhibiting Caspase-3/8 related apoptotic pathway, and activating the Bcl-2-related antiapoptotic pathway. Furthermore, current combination therapy also increased the expression levels of PDX-1 and CK-19 genes, and finally accelerated the proliferation and differentiation of pancreatic β-cells. In addition, combination therapy could also ameliorate the pathological characteristics of diabetic nephropathy in NOD mice.

CONCLUSION

Combination treatment with Adv-mIGF-1 gene and anti-CD20 mAbs may exert a potential beneficial role on T1D in NOD mice.

MicroRNA Sequences Modulated by Beta Cell Lipid Metabolism: Implications for Type 2 Diabetes Mellitus

Alterations in lipid metabolism within beta cells and islets contributes to dysfunction and apoptosis of beta cells, leading to loss of insulin secretion and the onset of type 2 diabetes. Over the last decade, there has been an explosion of interest in understanding the landscape of gene expression which influences beta cell function, including the importance of small non-coding microRNA sequences in this context. This review sought to identify the microRNA sequences regulated by metabolic challenges in beta cells and islets, their targets, highlight their function and assess their possible relevance as biomarkers of disease progression in diabetic individuals. Predictive analysis was used to explore networks of genes targeted by these microRNA sequences, which may offer new therapeutic strategies to protect beta cell function and delay the onset of type 2 diabetes.

The Study on the Active Ingredients and Potential Targets of Rice Bran Petroleum Ether Extracts for Treating Diabetes Based on Network Pharmacology

AIM AND OBJECTIVE

In ancient China, rice bran was used to treat diabetes and hyperlipidemia. The aim of this paper is to explore the active compounds and underlying mechanism of Rice Bran Petroleum Ether extracts (RBPE) against diabetes using network pharmacology.

MATERIALS AND METHODS

Gas chromatography-mass spectrometer analysis was performed to identify the chemical composition in RBPE. Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform, Swiss Target Prediction database, BATMAN-TCM, comprehensive database of human genes and gene phenotypes, therapeutic target database, DurgBank and GeneCards database were used to screen targets. The "component-target-disease" interactive network was constructed by Cytoscape software. Gene ontology and pathways related to the targets were analyzed by ClueGO, and core targets were screened by the MCODE, and Autodock vina was used for molecular docking.

RESULTS

The compounds with a percentage greater than 1.0% were selected for subsequent analysis. The RBPE contains oleic acid, (E)-9-Octadecenoic acid ethyl ester, and other chemical components that can regulate insulin, mitogen-activated protein kinase 3, epidermal growth factor receptor, mitogen-activated protein kinase 1, and other genes, which were mainly related to Pathways in cancer, Human cytomegalovirus infection and AGE-RAGE signaling pathway in diabetic complications, etc. The affinity of the core compounds and the corresponding protein of the gene targets was good.

CONCLUSION

The results of network pharmacology analysis indicate that the RBPE has multiple anti- diabetic ingredients, and RBPE exert anti-diabetic activity through multiple targets and signaling pathways. The present study can provide a scientific basis for further elucidating the mechanism of RBPE against diabetes.

Quail (Coturnix japonica) egg attenuated 2-butoxyethanol-induced enzymatic dysregulation, disseminated thrombosis and hemolytic impairment in female wistar rats

Influence of quail egg on pathologies has increased research interests and series of investigations are currently being done on its influence against these pathologies. The influence of quail egg against 2-butoxyethanol induced hemolysis and disseminated thrombosis was investigated to determine the enzymatic regulations that ensue in the amelioration of deleterious hemolytic and disseminated thrombosis displayed in female Wistar rats. Quail egg was separated into three (3) components (extracts)-quail egg yolk water soluble (QYWS) and fat soluble (QYFS), and albumen extract (QA) and the inorganic and organic compositions were characterized. Depranocytotic assaults was achieved by 250 mg/kg of 2-Butoxyethanol administered for 4 days, the clinical observation revealed a dark purple-red discoloration on the distal tails of the rats and therapeutic applications followed with 1000 mg/kg BWT of QYWS, QYFS and QA, and 15 mg/kg BWT of hydroxyurea. Morphological evaluation, haematological estimations and biochemical evaluations of the influence on the activities of sphingosine kinase-1, RNase, red cell carbonic anhydrase, lactate dehydrogenase, glutathione peroxidase and caspase-3, vis a vis the concentrations of sphingosine-1 phosphate, selenium and zinc (plasma and urine). In vitro anti-inflammatory influence of quail egg components were investigated against hemolysis and key enzymes of inflammation-cycloxygenase, lipoxygenase and β-glucuronidase. The in vitro anti-inflammatory effects of QYWS, QYFS and QA were concentration dependent from 200 to 800 μg/ml against hemolysis and the key enzymes of inflammation. The characterization of inorganic and organic bioactive composition of the yolk and albumen revealed the presence of folic acid, cobalamin, pyridine, riboflavin, ascorbic acid as well as vitamins D and E, selenium, zinc, iron and calcium. These had reflected in the attenuation of the induced hemolytic and disseminated thrombosis by regulations of enzymes linked to the infarction, apoptosis and oxidative stress characterized in sickle cell index.

Gene Expression Profiling of Apoptotic Proteins in Circulating Peripheral Blood Mononuclear Cells in Type II Diabetes Mellitus and Modulation by Metformin

INTRODUCTION

Insulin resistance in obesity and type 2 diabetes mellitus (T2DM) is associated with cardiovascular complications such as atherosclerosis. On the other hand, the reduction of apoptosis in macrophages has been linked with accelerated atherosclerosis. Apoptosis is controlled by a different family of proteins including Bcl-2 and caspases.

METHODS

To examine apoptosis in insulin resistance, we assessed the mRNA expression by qRT-PCR of several Bcl-2 family members, as well as caspase-3, -7, -8, and -9 in peripheral blood mononuclear cells (PBMCs) isolated from lean, obese, diabetic, and diabetic on metformin individuals.

RESULTS

PBMCs of diabetic individuals exhibited reduced expression of caspase-7 and increased expression of Bcl-10, Bad, Bax, Bid, and caspase-3. T2DM on metformin group had significantly higher Bad, Bax, and caspase-7 expression.

DISCUSSION

The moderate up-regulation of pro-apoptotic Bcl-10, Bax, Bad, Bid, and the effector caspase-3 coupled with inhibition of caspase-7 in circulating PBMCs of T2DM could be the result of increased inflammation in T2DM. Metformin treatment significantly inhibited the expression of Bcl-10, Bid, and caspase-3 and upregulated Bad/Bax/caspase-7 pathway suggesting the activation of Bad/Bax/caspase-7 apoptotic pathway. Further studies are warranted to elicit the underlying apoptotic pathways of PBMCs in T2DM and following metformin treatment.

Assessment of common and differentially expressed proteins between diabetes mellitus and fatty liver disease: a network analysis

AIM

This study aimed to introduce the main biomarkers related to NFLD and diabetes II to determine common pathogenic and metabolite factors linking NFLD to diabetes II.

BACKGROUND

Nonalcoholic fatty liver disease (NFLD) is chronic hepatic failure with a broad range of hepatic disorders. NFLD and diabetes type 2 coexist regularly to drive adverse outcomes such as hepatocellular carcinoma and vascular complications.

METHODS

The proteins related to NFDL and diabetes mellitus were extracted from String database. Proteins related to each disease were included in protein-protein interaction networks in Cytoscape software. Obtained networks were analyzed using Cytoscape network analyzer. The central nodes were determined as top hubs based on degree value. The top hubs related to NFLD and diabetes mellites were compared.

RESULTS

In total, 200 proteins related to NFDL and diabetes mellitus were found separately in String database and connected through undirected edges in individual networks. Central nodes based on degree value were determined for each disease. Ten percent of top nodes were selected based on degree value as the 20 top hubs for each disease. Target common hub proteins between NFDL and diabetes mellitus comprised INS, AKT1, ALB, PPARG, IL6, GPDPH, LEP, TNF, ADIPOQ, IGF1, TP53, MAPK3, and SIRT1.

CONCLUSION

According to the results, 13 common and 14 discriminatory central dysregulated proteins were determined for NAFLD and diabetes mellitus.

Plant Compounds for the Treatment of Diabetes, a Metabolic Disorder: NF-κB as a Therapeutic Target

Background:

The prevalence of diabetes in the world population hás reached 8.8 % and is expected to rise to 10.4% by 2040. Hence, there is an urgent need for the discovery of drugs against therapeutic targets to sojourn its prevalence. Previous studies proved that NF-κB serves as a central agent in the development of diabetic complications.

Objectives:

This review intended to list the natural plant compounds that would act as inhibitors of NF-κB signalling in different organs under the diabetic condition with their possible mechanism of action.

Methods:

Information on NF-κB, diabetes, natural products, and relation in between them, was gathered from scientific literature databases such as Pubmed, Medline, Google scholar, Science Direct, Springer, Wiley online library.

Results and Conclusion:

NF-κB plays a crucial role in the development of diabetic complications because of its link in the expression of genes that are responsible for organs damage such as kidney, brain, eye, liver, heart, muscle, endothelium, adipose tissue and pancreas by inflammation, apoptosis and oxidative stress. Activation of PPAR-α, SIRT3/1, and FXR through many cascades by plant compounds such as terpenoids, iridoids, flavonoids, alkaloids, phenols, tannins, carbohydrates, and phytocannabinoids recovers diabetic complications. These compounds also exhibit the prevention of NF-κB translocation into the nucleus by inhibiting NF-κB activators, such as VEGFR, RAGE and TLR4 receptors, which in turn, prevent the activation of many genes involved in tissue damage. Current knowledge on the treatment of diabetes by targeting NF-κB is limited, so future studies would enlighten accordingly.

Antinuclear antibodies in follicular fluid may reduce efficacy of in vitro fertilization and embryo transfer by invading endometrium and granular cells

PROBLEM

The mechanism(s) by which antinuclear antibodies (ANA) induce implantation failure are not clear, and little information regarding the function of autoantibodies in reproductive tissues is available.

METHODS OF STUDY

A total of 380 patients who underwent in vitro fertilization and embryo transfer (IVF-ET) were divided into control, serum positive, and follicular fluid (FF) positive groups based on the results of indirect immunofluorescence assay for ANA in the serum and FF. Immunofluorescence assay was performed to evaluate the existence of ANA in granular cells and endometrial tissues. Presence in FF of soluble apoptotic markers, including Bcl-2, Caspase-3, cleaved PARP, Cytochrome C, GAPDH, and p53, was assessed using magnetic bead based assays.

RESULTS

The patients in the FF positive group had the lowest numbers of retrieved oocytes, fertilizations, and high-quality embryos. The fertilization rate, and the proportion of two pronuclear (2PN) embryos in patients in the FF positive group were significantly lower than those in the other two groups. The FF positive group also had the lowest clinical pregnancy rate, and the highest early miscarriage rate. Granulosa cells and endometrial tissues in patients in the FF positive group were ANA positive. High levels of BCL-2, Caspase-3, Cytochrome C, GAPDH, and p53 were found in the FF of patients in the FF positive group.

CONCLUSIONS

Antinuclear antibodies in FF and endometrial tissues may cause imbalanced apoptosis, resulting in poor IVF-ET treatment outcomes. Local autoimmunity and cell apoptosis in reproductive tissues could be considered new therapeutic targets for improving IVF-ET treatment efficacy.

Combination therapy with anti-CD20 mAb and IL-10 gene to reverse type 1 diabetes by attenuating pancreatitis and inhibiting apoptosis in NOD mice

AIMS

To assess the combination therapy of anti-CD20 mabs and adenovirus-mediated interleukin-10 (IL-10) gene delivery on the prevention of type 1 diabetes (T1D) in non-obese diabetes (NOD) mice.

MAIN METHODS

In present study, we simultaneously blocked the B cell interactions and recovered the Th cell subset proportion by using through anti-CD20 Mab and adenovirus-mediated gene delivery of IL-10, respectively. After 9 consecutive days of combination therapy, various measurements, including hematoxylin-eosin staining (HE), terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labelling assay (TUNEL), immunohistochemistry, ELISA, PCR and western blot were applied to further assess the efficacy.

KEY FINDINGS

The results suggested that the combination intervention reduced the T1D-associated morbidity of NOD mice, promote insulin secretion, control blood glucose and ease pancreatitis. Moreover, the combination therapy might play a protective role in pancreatic β cells by suppressing the expression of TNF-α and Fas, blocking the Caspase-8 and Caspase-3 apoptotic pathways and activating the Bcl-2 anti-apoptotic pathway. Finally, the combination intervention may up-regulate the gene expression of CK-19 and PDX-1 and further accelerate the differentiation and proliferation of pancreatic β cells.

SIGNIFICANCE

Therefore, the combination intervention with anti-CD20 mabs and the IL-10 gene plays a role in the prevention of T1D to some extent in NOD mice.

Dacryodes edulis (G. Don) H.J. Lam modulates glucose metabolism, cholinergic activities and Nrf2 expression, while suppressing oxidative stress and dyslipidemia in diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Dacryodes edulis L. is an evergreen tree indigenous to western and eastern Africa which is utilized for nutritional and medicinal purposes. Folklorically, different parts of the tree are used in treating and managing diabetes and its complications.

AIMS

The antidiabetic effect of the butanol fraction of D. edulis ethanol extract (BFDE) was studied in fructose-streptozotocin induced type 2 diabetic rats.

METHODS

The ethanol extract was fractionated to yield the hexane, dichloromethane, ethyl acetate, butanol and aqueous fractions. The in vitro antidiabetic activities of the fractions were determined by their ability to inhibit α-glucosidase activity. BDFE was the most active and showed no cytotoxic effect while stimulating glucose uptake in 3T3-L1 adipocytes. Thus, selected for in vivo study. Diabetic rats were grouped into 4. The negative control group was administered water only, another group was treated with metformin (200 mg/kg bodyweight), while the other groups were administered BDFE at 150 and 300 mg/kg bodyweight respectively. Two other groups consisting of normal rats were given water and BFDE (300 mg/kg bodyweight) respectively, with the former serving as normal control. After 6 weeks of intervention, the rats were humanely sacrificed using appropriate anaesthesia.

RESULTS

Treatment with the fraction significantly (p < 0.05) reduced the blood glucose level of the diabetic rats, with concomitant increase in serum insulin secretion. It also caused significant (p < 0.05) elevation of reduced glutathione level, superoxide dismutase, catalase, α-amylase, and ATPase activities, with concomitant depletion in myeloperoxidase activity, NO and MDA levels of the serum and pancreas. The pancreatic morphology and β-cell function were significantly improved in BFDE-treated rats, with restoration of the pancreatic capillary networks. Treatment with BFDE significantly (p < 0.05) inhibited the activities of glycogen phosphorylase, fructose 1,6 biphosphatase, glucose 6 phosphatase, and acetylcholinesterase, while suppressing the expression of Nrf2. HPLC analysis revealed the presence of gallic acid, vanillic acid, vanillin, and (-)-epicatechin in the fraction.

CONCLUSION

These results portray the antidiabetic and antioxidative properties of BFDE, which may be a synergistic consequence of the identified phenolics.

Vitamin D metabolites influence expression of genes concerning cellular viability and function in insulin producing β-cells (INS1E)

BACKGROUND

Studies have shown that vitamin D can enhance glucose-stimulated insulin secretion (GSIS) and change the expression of genes in pancreatic β-cells. Still the mechanisms linking vitamin D and GSIS are unknown.

MATERIAL AND METHODS

We used an established β-cell line, INS1E. INS1E cells were pre-treated with 10 nM 1,25(OH)₂vitamin D or 10 nM 25(OH)vitamin D for 72 h and stimulated with 22 mM glucose for 60 min. RNA was extracted for gene expression analysis.

RESULTS

Expression of genes affecting viability, apoptosis and GSIS changed after pre-treatment with both 1,25(OH)₂vitamin D and 25(OH)vitamin D in INS1E cells. Stimulation with glucose after pre-treatment of INS1E cells with 1,25(OH)₂vitamin D resulted in 181 differentially expressed genes, whereas 526 genes were differentially expressed after pre-treatment with 25(OH)vitamin D.

CONCLUSION

Vitamin D metabolites may affect pancreatic β-cells and GSIS through changed gene expression for genes involved in β-cell function and viability.

Biochemical Implications of Biotransformation of Some Toxic Floras Using Natural Local Enzyme Sources

BACKGROUND

Recently, it has been established that simultaneous saccharification and fermentation is a potent technique for the detoxification of harmful plant materials.

OBJECTIVE

Following encouraging simultaneous medicinal applications of snail slime and yeast, we exploited their hydrolytic and fermentation potentials to prevent toxicities of the selected floras; Erythrodontium barteri (EB), bracken fern (BF), and crustose lichens (CL). The applicability of the saccharification process has been described in a patent (WO2005010193A2).

METHODS

The plants were bioprocessed using snail digestive juice and yeast slurry and their health effects were evaluated. Seventy rats were divided equally into groups, treated with single doses of aqueous extracts of the plants and their bioprocessed forms, and compared with control rats.

RESULTS

The plants showed very high antinutrients levels, which significantly reduced after SSF with enhanced flavonoids, alkaloids and phenols. Potential alterations of WBC differentials, RBC, liver and renal function markers indices were mitigated by bioprocessed extracts. MDA, SOD, GRase, XO and XDH levels in rats administered the bEB and CL were equivalent to the levels found for the control rats. Some bioprocessed plants produced unaltered insulin, ghrelin, and leptin levels. The bioprocessed extracts, when compared to the effects of unprocessed extracts, produced lower TNF-α, Caspase-3, and adiponectin levels and mitigated the potential suppression of Na+/K+-ATPase levels. Potential depletion of inhibin-B, testosterone, estrogen, and prolactin was mitigated after bioprocessing.

CONCLUSION

This study, thus, validates the application of bioprocessing using snail digestive juice and yeast as an effective approach to reduce the potential toxicities of harmful plants.

A comparative study of the role of crocin and sitagliptin in attenuation of STZ-induced diabetes mellitus and the associated inflammatory and apoptotic changes in pancreatic β-islets

Type 1 diabetes mellitus (T1DM) describes a complex group of metabolic disorders associated with elevated blood glucose levels and increased risks of complications development. Exploring new drug therapies would reduce the increased diabetes-associated morbidity and mortality and will reduce the excessive health care costs. Crocin is the major active ingredient of saffron. In the current study, DM was induced by single intraperitoneal injection of streptozocin (50 mg/kg).DM progression was associated with a significant increase in blood glucose level with reduced insulin and increased glucagon secretion. Pancreatic malondialdehyde (MDA) content significantly escalated, while superoxide dismutase (SOD) activity, reduced glutathione (GSH) concentration, catalase activity, thioredoxin level and serum total antioxidant capacity significantly declined. This was associated with a significant increase in pancreatic caspase-3 contents and pancreatic infiltration with inflammatory cells in β-islets. Both sitagliptin and crocin significantly reduced blood glucose levels, enhanced pancreatic insulin expression and secretion and suppressed glucagon secretion with enhancement of anti-oxidant defenses and reduction of oxidative burden, with evident anti-inflammatory impacts. Interestingly, the effect of crocin on DM indices, inflammatory and apoptotic changes was comparable to that of sitagliptin; the standard oral hypoglycemic agent. Nevertheless, crocin had a superior effect compared to sitagliptin on blood sugar level, β-islets diameter and insulin immune-reactivity. In conclusion, crocin reduced blood glucose level mainly via reduction of oxidative burden, modulation of apoptotic pathway and attenuation of pancreatic inflammation.

Anti-oxidant, anti-apoptotic, anti-hypoxic and anti-inflammatory conditions induced by PTY-2 against STZ-induced stress in islets

The earlier assessment of Pueraria tuberosa (PT) has shown anti-diabetic effects through enhancing incretin action and DPP-IV (Dipeptidyl peptidase-IV) inhibition. The aim of this work was to further explore the protective role of aqueous extract of Pueraria tuberosa tuber (PTY-2) against streptozotocin (STZ) induced islet stress in rats. Diabetes was induced by STZ (65 mg/kg body weight) in charles foster male rats. After 60 days of STZ administration, animals with blood glucose levels > 200 g/dL were considered as diabetic. All the rats were later divided into three groups: Group-1 (STZ untreated normal rats), Group-2 (Diabetic control), and Group-3 (PTY-2 [50 mg/100 g bw treatment for next 10 days to diabetic rats). The rats were then sacrificed after the 10^th day of treatment accordingly. STZ treatment led to an increase in expression of Matrix metalloproteinases-9 (MMP-9), Tumour necrosis factor-α (Tnf-α), Hypoxia inducible factor-α (HIF-1α), Vascular endothelial growth factor (VEGF), Interleukin-6 (IL-6), Protein kinase C-ε (PKC-ε), Nuclear factor kappa-light-chain-enhancer of activated B-cells (NFkB), and Caspase-3. Reverse Transcriptase-PCR (RT-PCR), Immunohistochemistry and Western-Blot analysis showed an increase in the expressions of Superoxide Dismutase (SOD) and Nephrin, and a decrease in the expressions of NFkB, PKC-ε, TNF-α, MMP-9, HIF-1α, VEGF, Caspase-3 and IL-6 after 10 days of PTY-2 treatment. The results showed that PTY-2 favorably changed all the expressions via anti-oxidant, anti-apoptotic, anti-hypoxic and anti-inflammatory pathways, making itself as a protective agent against STZ induced islet stress. Further evaluation of PTY-2 might be helpful in establishing its role in the management of diabetes mellitus.

Anti-Diabetic Effect of a Shihunine-Rich Extract of Dendrobium loddigesii on 3T3-L1 Cells and db/db Mice by Up-Regulating AMPK-GLUT4-PPARα

The stems of Dendrobium loddigesii, a Chinese herb, are often used to treat diabetes and its polar extract is rich in shihunine, a water-soluble Orchidaceae alkaloid, but little is known about the anti-diabetes effects and mechanism of shihunine. This study investigated the anti-diabetic effect of a shihunine-rich extract of D. loddigesii (DLS) based on 3T3-L1 cells and db/db mice. The underlying mechanisms were primarily explored using Western blot analysis and immunohistochemical staining. The 3T3-L1 cell experiments showed that DLS can reduce the intracellular accumulation of oil droplets as well as triglycerides (p < 0.001) and promote the 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]-2deoxyglucose (2-NBDG) uptake of 3T3-L1 cells (p < 0.001). The animal experiments confirmed that after 8 weeks of DLS treatment, the body weight, fasting blood sugar, and serum lipid levels of mice were significantly lowered, and the oral glucose tolerance test and serum insulin level were significantly improved compared to the no-treatment diabetes mellitus group. Further histomorphology observation led to the conclusion that the quantities of islet cells were significantly increased and the increase in adipose cell size was significantly suppressed. The immunohistochemical test of pancreatic tissue revealed that DLS inhibited the expression of cleaved cysteine aspartic acid-specific protease 3 (cleaved caspase-3). Western blot experiments showed that DLS had agonistic effects on adenosine monophosphate (AMP)-activated protein kinase phosphorylation (p-AMPK) and increased the expression levels of peroxisome proliferator-activated receptor α (PPARα) and glucose transporter 4 (GLUT4) in liver or adipose tissues. These data suggest that the shihunine-rich extract of D. loddigesii is an anti-diabetic fraction of D. loddigesii. Under our experimental condition, DLS at a dose of 50 mg/kg has good anti-diabetic efficacy.

Raffia palm (Raphia hookeri G. Mann & H. Wendl) wine modulates glucose homeostasis by enhancing insulin secretion and inhibiting redox imbalance in a rat model of diabetes induced by high fructose diet and streptozotocin

ETHNOPHARMACOLOGICAL RELEVANCE

Raffia palm (Raphia hookeri) wine (RPW) is amongst the natural products from plants, utilized singly or in combination with other medicinal plants for the treatment of several ailments including Diabetes Mellitus (DM). However, there is a scientific dearth on its antidiabetic activity.

AIM

The antidiabetic effect of RPW and its possible mechanism of actions were investigated in diabetic rats.

METHODS

Four groups of male SD rats were first supplied with 10% fructose solution ad libitum for 2 weeks instead of drinking water followed by an intraperitonial injection of streptozotocin (40 mg/kg) to induce diabetes. Two diabetic groups were administered RPW at 150 and 300 mg/kg bodyweight (BW) respectively; a group was administered with metformin, while the other one was served as a negative control. Two groups of normal rats were administered with water and RPW (300 mg/kg BW) and served as normal control and normal toxicology group, respectively.

RESULTS

Five weeks treatment of RPW led to significant (p < 0.05) increase in serum insulin and HDL-c levels with concomitant reduction in blood glucose, fructosamine, ALT, uric acid, triglycerides and LDL-c levels in diabetic rats. Rats treated with RPW had elevated levels of GSH, SOD, catalase, ATPase and α-amylase activities, while reduced NO level and myeloperoxidase activity was observed in their serum and pancreatic tissues. RPW also improved pancreatic β-cell function and restored β- and acinar cells morphology, and capillary networks. The activities of glycogen phosphorylase, fructose 1,6 biphosphatase, glucose-6-phosphatase, and acetylcholinesterase were also inhibited in RPW-treated diabetic rats, with concomitant down regulation of Nrf2 gene expression.

CONCLUSION

The data of this study suggest that RPW modulates glucose homeostasis by enhancing insulin secretion as well as inhibiting redox imbalance in diabetic rats, which may be attributed to the synergetic effects of its phytochemical constituents as identified by GC-MS analysis.

Protective effect of hypoxylonol C and 4,5,4',5'-tetrahydroxy-1,1'-binaphthyl isolated from Annulohypoxylon annulatum against streptozotocin-induced damage in INS-1 cells

We evaluated the protective effects of hypoxylonol C and 4,5,4',5'-tetrahydroxy-1,1'-binaphthyl (BNT) isolated from Annulohypoxylon annulatum on pancreatic β-cell apoptosis, using the β-cell toxin streptozotocin (STZ). Hypoxylonol C and BNT restored the STZ-induced decrease in INS-1 cell viability in a dose-dependent manner. In addition, treatment of INS-1 cells with 50 μM STZ resulted in an increase in apoptotic cell death, which was observed as annexin V fluorescence intensity. Apoptotic cell death was decreased by co-treatment with 100 μM hypoxylonol C and 100 μM BNT. Similarly, STZ caused a marked increase in the expression of cleaved caspase-8, caspase-3, Bax, and poly (ADP-ribose) polymerase (PARP), as well as a decrease in the expression of B-cell lymphoma 2 (Bcl-2), which was reversed by co-treatment with 100 μM hypoxylonol C and 100 μM BNT. These findings suggest that hypoxylonol C and BNT play an important role in protecting pancreatic β-cells against apoptotic damage.

The Effects of Urtica dioica and Lamium album Extracts on the Expression Level of Cyclooxygenase-2 and Caspase-3 in the Liver and Kidney of Streptozotocin-Induced Diabetic Rats

Background: Diabetes seems to be associated with increased inflammation and induced apoptosis in several tissues. Urtica dioica and Lamium album have shown to possess a variety of beneficial properties like anti-inflammatory effects. In this experimental study, we tried to evaluate the effects of U. dioica and L. album extracts on the expression level of cyclooxygenase-2 (COX-2; as an inflammation marker) and caspase-3 (CASP-3; as an apoptotic marker) in the liver and kidney tissues of diabetic rats. Methods: Thirty-two male Wistar rats were randomly allocated to four groups: normal control, diabetic control, diabetic treated with U. dioica (100 mg/kg/daily), and diabetic treated with L. album (100 mg/kg/daily) for 28 days. At the end of the study, liver and kidney tissues were harvested and mRNA expression level of COX-2 and CASP-3 was determined by real-time PCR technique. Also, serum glucose was measured. Results: Liver COX-2 mRNA in diabetic rats was significantly higher than normal control rats (P=0.02). However, U. dioica and L. album caused significant decrease in mRNA expression of liver COX-2 in diabetic rats (P=0.015 and P=0.03, respectively). Also, in diabetic rats treated with both extracts, serum glucose was remarkably lower than diabetic control rats (P<0.0001 and P<0.01, respectively). Conclusion: It appears that U. dioica and L. album might decrease liver damage by decreasing the inflammatory effects of COX-2 in streptozocin-induced diabetic rats. Since these plant extracts may influence diabetes by several mechanisms, further research in this field is warranted.

Involvement of the STAT5-cyclin D/CDK4-pRb pathway in β-cell proliferation stimulated by prolactin during pregnancy

During pregnancy, maternal pancreatic β-cells undergo a compensatory expansion in response to the state of insulin resistance, where prolactin (PRL) plays a major role. Retinoblastoma protein (Rb) has been shown to critically regulate islet proliferation and function. The aim of the study was to explore the role of Rb in β-cell mass expansion during pregnancy. Expression of pocket protein family and E2Fs were examined in mouse islets during pregnancy and in insulinoma cells (INS-1) stimulated by PRL. PRL-stimulated INS-1 cells were used to explore the signaling pathway that regulates Rb downstream of the PRL receptor. Pancreas-specific Rb-knockout (Rb-KO) mice were assessed to evaluate the in vivo function of Rb in β-cell proliferation during pregnancy. During pregnancy, expression of Rb, phospho-Rb (p-Rb), p107, and E2F1 increased, while p130 decreased in maternal islets. With PRL stimulation, induction of Rb expression occurred mainly in the nucleus, while p-Rb was predominantly in the cytoplasm. Inhibition of STAT5 significantly restrained the expression of CDK4, Rb, p-Rb, and E2F1 in PRL-stimulated INS-1 cells with attenuation in cell cycle progression. Reduction of Rb phosphorylation by CDK4 inhibition blocked PRL-mediated proliferation of INS-1 cells. On the other hand, knockdown of Rb using siRNA led to an induction in E2F1 leading to cell cycle progression from G₁ to S and G₂/M phase, similar to the effects of PRL-mediated induction of p-Rb that led to cell proliferation. With Rb knockdown, PRL did not lead to further increase in cell cycle progression. Similarly, while Rb-KO pregnant mice displayed better glucose tolerance and higher insulin secretion, they had similar β-cell mass and proliferation to wild-type pregnant controls, supporting the essential role of Rb suppression in augmenting β-cell proliferation during pregnancy. Rb-E2F1 regulation plays a pivotal role in PRL-stimulated β-cell proliferation. PRL promotes Rb phosphorylation and E2F1 upregulation via STAT5-cyclin D/CDK4 pathway during pregnancy.

Antidiabetic potential of saffron and its active constituents

The prevalence of diabetes mellitus is growing rapidly worldwide. This metabolic disorder affects many physiological pathways and is a key underlying cause of a multitude of debilitating complications. There is, therefore, a critical need for effective diabetes management. Although many synthetic therapeutic glucose-lowering agents have been developed to control glucose homeostasis, they may have unfavorable side effects or limited efficacy. Herbal-based hypoglycemic agents present an adjunct treatment option to mitigate insulin resistance, improve glycemic control and reduce the required dose of standard antidiabetic medications. Saffron (Crocus sativus L.), whilst widely used as a food additive, is a natural product with insulin-sensitizing and hypoglycemic effects. Saffron contains several bioactive β carotenes, which exert their pharmacological effects in various tissues without any obvious side effects. In this study, we discuss how saffron and its major components exert their hypoglycemic effects by induction of insulin sensitivity, improving insulin signaling and preventing β-cell failure, all mechanisms combining to achieve better glycemic control.

Novel roles of apoptotic caspases in tumor repopulation, epigenetic reprogramming, carcinogenesis, and beyond

Apoptotic caspases have long been studied for their roles in programmed cell death and tumor suppression. With recent discoveries, however, it is becoming apparent these cell death executioners are involved in additional biological pathways beyond killing cells. In some cases, apoptotic cells secrete growth signals to stimulate proliferation of neighboring cells. This pathway functions to regenerate tissues in multiple organisms, but it also poses problems in tumor resistance to chemo- and radiotherapy. Additionally, it was found that activation of caspases does not irreversibly lead to cell death, contrary to the established paradigm. Sub-lethal activation of caspases is evident in cell differentiation and epigenetic reprogramming. Furthermore, evidence indicates spontaneous, unprovoked activation of caspases in many cancer cells, which plays pivotal roles in maintaining their tumorigenicity and metastasis. These unexpected findings challenge current cancer therapy approaches aimed at activation of the apoptotic pathway. At the same time, the newly discovered functions of caspases suggest new treatment approaches for cancer and other pathological conditions in the future.

Toxoplasma gondii as a possible causative pathogen of type-1 diabetes mellitus: Evidence from case-control and experimental studies

Toxoplasma gondii is the causative parasite of an important worldwide disease. This obligate intracellular parasite can infect and replicate inside any nucleated cells including those of pancreas. Insulin is a hormone secreted by the pancreas and is responsible for controlling blood glucose concentration. Deficiency of insulin production accounts for the occurrence of type-1 diabetes mellitus (T1D). Thus, theoretically, toxoplasmosis could play a possible role in the development of T1D. However, the studies on this theory are still insufficient; therefore, this work was designed. Interestingly, in the case-control study, seropositivity of anti-Toxoplasma IgG was significantly higher among T1D (86.37%) in comparison with T2D (66.67%) and the control group (60%). Moreover, the odd ratio of chronic toxoplasmosis was 4.2 folds higher among T1D patients than among controls. The experimental study included acute and chronic Me49 T. gondii infected mice groups in addition to a control group. Pathological examination revealed the presence of T. gondii zoites adjacent to the islets of Langerhans and in pancreatic parenchyma of acutely infected mice. With chronic infection, there was a significant reduction of islets number and sizes in association with grade-1 insulitis. Additionally, the immunohistochemical study showed significant infiltration of the islets of chronically infected mice by CD8⁺ and CD45⁺ immune cells. In contrary to the control group, the islets of the chronic group showed significantly higher expression of the apoptotic marker caspase-3 and a significantly lower expression of the proliferation marker Ki69. Finally, a significant reduction of insulin expression in the islets of chronic infection group was detected in association with a significant increase in serum glucose concentrations; however, the establishment of diabetes did not occur throughout this work. Thus, this study presents an evidence for the probable role of chronic toxoplasmosis in the development of T1D which should be considered in further studies.

Regulation of stressed-induced cell death by the Bcl-2 family of apoptotic proteins

Apoptosis is often deregulated in a number of human diseases. Heat-induced apoptosis is a model system for studying the consequences of protein misfolding and is mediated by the Bcl-2 family of proteins. This family consists of both pro-apoptotic and anti-apoptotic members that control mitochondrial integrity. The BH3-only pro-apoptotic members are strong inducers of apoptotic cell death. Protein damaging stress can activate a process of cellular destruction known as apoptosis. The pro-apoptotic BH3-only proteins and transcription factors activate this death pathway by inhibiting the anti-apoptotic Bcl-2 family proteins eliminating cancer cells in a short period of time.

Pharmacotherapy with Thymoquinone Improved Pancreatic β-Cell Integrity and Functional Activity, Enhanced Islets Revascularization, and Alleviated Metabolic and Hepato-Renal Disturbances in Streptozotocin-Induced Diabetes in Rats

Aims: This study is aimed at evaluating the antidiabetic effects of thymoquinone (TQ) on streptozotocin (STZ)-induced diabetes in rats, and exploring the possible underlying mechanisms. Methods: Diabetes was induced in adult male Wistar rats by intraperitoneal injection of freshly prepared STZ (65 mg/kg). After disease induction, 42 rats were equally assigned to: controls, STZ-diabetic group, and STZ-diabetic group treated with oral TQ (35 mg/kg/day) for 5 weeks. Fasting blood glucose levels were determined weekly, and the animals were euthanized at day 38 post-STZ injection. Blood samples were assessed for glucose-insulin homeostasis parameters (plasma glucose, glycated hemoglobin, serum insulin, homeostatic model assessment of insulin resistance, and insulin sensitivity index) and lipid profile. Resected pancreases were subjected to histological examination and immunohistochemical or enzyme-linked immunosorbent assay assessment to determine the pancreatic expression of insulin sensitizing β-cells, anti-apoptotic protein “survivin,” apoptosis-inducer “caspase-3,” prototypic angiogenic factors (vascular endothelial growth factor [VEGF] and endothelial cluster of differentiation 31 [CD31]), pro- and anti-inflammatory cytokines (interleukin-1beta [IL-1β] and interleukin-10 [IL-10], respectively), thiobarbituric acid reactive substances (TBARS), total glutathione (GSH), and superoxide dismutase (SOD). The hepato-renal statuses were assessed biochemically and histologically. Results: Therapy with TQ markedly improved the integrity of pancreatic islets, glucose-insulin homeostasis-related parameters, lipid profile parameters, and hepato-renal functional and histomorphological statuses that collectively were severely deteriorated in untreated diabetic group. Mechanistically, TQ therapy efficiently increased insulin producing β-cells, upregulated survivin, VEGF, CD31, IL-10, GSH and SOD, and downregulated caspase-3, IL-1β, and TBARSs in the pancreatic tissues of STZ-diabetic rats. Conclusions: These findings prove the anti-diabetic potential of TQ and its efficacy in regenerating pancreatic β-cells and ameliorating pancreatic inflammation and oxidative stress, and highlight its novelty in repressing apoptosis of β-cells and enhancing islet revascularization in STZ-diabetic rats. Further studies are required to support these findings and realize their possible clinical significance.

Geniposide protects pancreatic β cells from high glucose-mediated injury by activation of AMP-activated protein kinase

Our previous works indicated that geniposide could regulate glucose-stimulated insulin secretion (GSIS), and improved chronic high glucose-induced dysfunctions in pancreatic β cells, but the molecular mechanisms remain largely unknown. In the present study, we investigated the role of 5'-AMP-activated protein kinase (AMPK) in high glucose induced cell injury and explored the associated molecular mechanisms in rat INS-1 pancreatic β cells. Data suggested that geniposide obviously prevented the cell damage induced by high (25 mM) glucose in INS-1 cells, which increased the protein levels of cell apoptosis-associated enzymes, including heme oxygenase-1 (HO-1), and Bcl-2, but apparently attenuated the protein level of Bax, an apoptotic protein. In addition, Compound C, an AMPK inhibitor, remarkably inhibited the effects of geniposide on the protein levels of HO-1, Bcl-2, and Bax, but AICAR, an AMPK activator, potentiated the role of geniposide on the protein levels of HO-1, Bcl-2, and Bax. More importantly, geniposide directly prevented the cleavage of caspase-3 induced by high glucose, and this effect was also evidently prohibited by the pre-incubation of compound C in high glucose-treated INS-1 cells. Furthermore, using the method of RNA interfere, we further proved that treatment with AMPK siRNA attenuated the effects of geniposide on the apoptosis-associated proteins and cell viability. All these data suggest that AMPK plays a crucial role on geniposide antagonizing high glucose-induced pancreatic β cells injury.

Baicalin attenuates lipopolysaccharide induced inflammation and apoptosis of cow mammary epithelial cells by regulating NF-κB and HSP72

Baicalin is the main ingredient of traditional Chinese herbal medicine, Scutellaria baicalensis, which has been widely used clinically as an anti-inflammatory agent. However, molecular mechanism of action of this drug is not yet clear. In the present study, the protective mechanism of baicalin against lipopolysaccharide (LPS) induced inflammatory injury in cow mammary epithelial cells (CMECs) was explored. For this purpose, in vitro cultured CMECs were treated with baicalin (10μg/mL) and LPS (10μg/mL) for 24 and 12h, respectively, and the cell viability was measured by using cell counting kit-8 (CCK-8). The results revealed that LPS induced inflammatory responses, as p-p65/p65 and p-IκBα/IκBα ratios and TNF-α and IL-1β production was increased in the CMECs. Both Bcl-2/Bax ratio and cell viability were decreased and caspase-3 cleaved following LPS treatment, indicating apoptosis of CMECs. Moreover, both LPS and baicalin increased HSP72 expression of the CMECs. However, cellular inflammatory responses and apoptosis were significantly reduced in baicalin treated CMECs. In conclusion, baicalin ameliorated inflammation and apoptosis of the CMECs induced by LPS via inhibiting NF-κB activation and up regulation of HSP72.

Antiaging Gene Klotho Attenuates Pancreatic β-Cell Apoptosis in Type 1 Diabetes

Apoptosis is the major cause of death of insulin-producing β-cells in type 1 diabetes mellitus (T1DM). Klotho is a recently discovered antiaging gene. We found that the Klotho gene is expressed in pancreatic β-cells. Interestingly, halplodeficiency of Klotho (KL(+/-)) exacerbated streptozotocin (STZ)-induced diabetes (a model of T1DM), including hyperglycemia, glucose intolerance, diminished islet insulin storage, and increased apoptotic β-cells. Conversely, in vivo β-cell-specific expression of mouse Klotho gene (mKL) attenuated β-cell apoptosis and prevented STZ-induced diabetes. mKL promoted cell adhesion to collagen IV, increased FAK and Akt phosphorylation, and inhibited caspase 3 cleavage in cultured MIN6 β-cells. mKL abolished STZ- and TNFα-induced inhibition of FAK and Akt phosphorylation, caspase 3 cleavage, and β-cell apoptosis. These promoting effects of Klotho can be abolished by blocking integrin β1. Therefore, these cell-based studies indicated that Klotho protected β-cells by inhibiting β-cell apoptosis through activation of the integrin β1-FAK/Akt pathway, leading to inhibition of caspase 3 cleavage. In an autoimmune T1DM model (NOD), we showed that in vivo β-cell-specific expression of mKL improved glucose tolerance, attenuated β-cell apoptosis, enhanced insulin storage in β-cells, and increased plasma insulin levels. The beneficial effect of Klotho gene delivery is likely due to attenuation of T-cell infiltration in pancreatic islets in NOD mice. Overall, our results demonstrate for the first time that Klotho protected β-cells in T1DM via attenuating apoptosis.

The effects of ozone therapy on caspase pathways, TNF-α, and HIF-1α in diabetic nephropathy

BACKGROUND

Accelerated apoptosis plays a vital role in the development of diabetic vascular complications. Ozone may attenuate diabetic nephropathy by means of decreased apoptosis-related genes. The aim of our study was to investigate the effect of ozone therapy on streptozotocin-induced diabetic nephropathy in rats. Also the histopathological changes in diabetic kidney tissue with ozone treatment were evaluated.

METHODS

The rats were randomly divided into six groups (n = 7): control (C), ozone (O), diabetic (D), ozone-treated diabetic (DO), insulin-treated diabetic (DI), and ozone- and insulin-treated diabetic (DOI). D, DI, and DOI groups were induced by a single intraperitoneal injection of streptozotocin. Ozone was given to the O, DO, and DOI groups. Group DI and DOI received subcutaneous (SC) insulin (3 IU). All animals received daily treatment for 6 weeks.

RESULTS

Expressions of caspase-1-3-9, HIF-1α, and TNF-α genes were significantly higher in D group compared to C group (p < 0.05 for all). Ozone treatment resulted in significant decrease in the expressions of these genes in diabetic kidney tissue compared to both C and D group (p < 0.05 for all). Caspase-1-3-9, HIF-1α, and TNF-α gene expressions were found to be lower in DOI group compared to C group (p < 0.05 for all). Also adding ozone treatment to insulin therapy resulted in more significantly decrease in the expressions of these genes in diabetic tissue compared to only insulin-treated diabetic group (p < 0.05 for all). Regarding histological changes, ozone treatment resulted in decrease in the renal corpuscular inflammation and normal kidney morphology was observed. Both insulin and ozone therapies apparently improved kidney histological findings with less degenerated tubules and less inflammation of renal corpuscle compared to D, DO, and DI groups.

CONCLUSION

Ozone therapy decreases the expressions of apoptotic genes in diabetic kidney tissue and improves the histopathological changes.

BH3-Only protein bmf is required for the maintenance of glucose homeostasis in an in vivo model of HNF1α-MODY diabetes

Heterozygous loss-of-function mutations in the hepatocyte nuclear factor 1α (HNF-1α) gene can lead to diminished amounts of functional HNF-1α, resulting in the onset of a particularly severe form of maturity-onset diabetes of the young (MODY). We have previously shown that induction of a dominant-negative mutant of HNF-1α (DNHNF-1α) results in the activation of the bioenergetic stress sensor AMP-activated protein kinase (AMPK), preceding the onset of apoptosis and the induction of pro-apoptotic Bcl-2 homology domain-3-only protein Bmf (Bcl-2-modifying factor) as a mediator of DNHNF-1α-induced apoptosis. Through the knockout of bmf in a transgenic mouse model with DNHNF-1α suppression of HNF-1α function in pancreatic beta-cells, this study aimed to examine the effect of loss-of-function of this BH3-only protein on the disease pathology and progression, and further elucidate the role of Bmf in mediating DNHNF-1α-induced beta-cell loss. Morphological analysis revealed an attenuation in beta-cell loss in bmf-deficient diabetic male mice and preserved insulin content. Surprisingly, bmf deficiency was found to exacerbate hyperglycemia in both diabetic male and hyperglycemic female mice, and ultimately resulted in a decreased glucose-stimulated insulin response, implicating a role for Bmf in glucose homeostasis regulation independent of an effect on beta-cell loss. Collectively, our data demonstrate that Bmf contributes to the decline in beta-cells in a mouse model of HNF1A-MODY but is also required for the maintenance of glucose homeostasis in vivo.

Prolactin-stimulated survivin induction is required for beta cell mass expansion during pregnancy in mice

AIMS/HYPOTHESIS

Prolactin (PRL)-stimulated beta cell proliferation is critical for maternal pancreatic beta cell mass expansion during pregnancy. However, the molecular effectors of the multiple putative signalling pathways downstream of the PRL receptor (PRL-R) are still elusive. Survivin has been shown to be induced during pregnancy. The aim of the present study was to define the essential role of survivin in gestational beta cell mass expansion.

METHODS

Expression of survivin was assessed in mouse islets during pregnancy and in insulinoma cells (INS-1) stimulated with PRL. Pregnant mice with targeted deletion of the survivin gene (also known as Birc5) in beta cells were assessed to determine the essential function of survivin in maternal beta cell mass expansion. INS-1 cells stimulated with PRL were used to explore the role of survivin in signalling pathways downstream of the PRL-R.

RESULTS

Survivin was significantly upregulated in maternal islets during pregnancy. With PRL stimulation, induction of survivin expression occurred predominantly in the nucleus and was associated with cell cycle progression to S and G2/M phase. Beta cell-specific survivin-knockout pregnant mice displayed glucose intolerance, attenuated beta cell mass expansion and impaired beta cell proliferation, with significant attenuation in the increased expression of Cdk4/Ccnd1, E2f1, p53 (also known as Trp53) and p21 (also known as Cdkn1a) compared with wild-type controls during pregnancy. Targeted deletion of survivin in INS-1 cells resulted in cell cycle disturbance with an arrest in G1/S phase after PRL stimulation. Inhibitors of Akt, signal transducer and activator of transcription 5 (STAT5), PIM or extracellular signal-regulated kinase (ERK), significantly decreased the expression of survivin in PRL-stimulated INS-1 cells.

CONCLUSIONS/INTERPRETATION

Survivin directly participates in PRL-mediated beta cell proliferation via Akt, STAT5-PIM and ERK signalling pathways during pregnancy.

TNF-α Antibody Therapy in Combination With the T-Cell-Specific Antibody Anti-TCR Reverses the Diabetic Metabolic State in the LEW.1AR1-iddm Rat

Anti-tumor necrosis factor-α (TNF-α) therapy (5 mg/kg body weight), alone or combined with the T-cell-specific antibody anti-T-cell receptor (TCR) (0.5 mg/kg body weight), was performed over 5 days immediately after disease manifestation to reverse the diabetic metabolic state in the LEW.1AR1-iddm rat, an animal model of human type 1 diabetes. Only combination therapy starting at blood glucose concentrations below 15 mmol/L restored normoglycemia and normalized C-peptide. Increased β-cell proliferation and reduced apoptosis led to a restoration of β-cell mass along with an immune cell infiltration-free pancreas 60 days after the end of therapy. This combination of two antibodies, anti-TCR/CD3, as a cornerstone compound in anti-T-cell therapy, and anti-TNF-α, as the most prominent and effective therapeutic antibody in suppressing TNF-α action in many autoimmune diseases, was able to reverse the diabetic metabolic state. With increasing blood glucose concentrations during the disease progression, however, the proapoptotic pressure on the residual β-cell mass increased, ultimately reaching a point where the reservoir of the surviving β-cells was insufficient to allow a restoration of normal β-cell mass through regeneration. The present results may open a therapeutic window for reversal of diabetic hyperglycemia in patients, worthwhile of being tested in clinical trials.