PSTi8 with metformin ameliorates perimenopause induced steatohepatitis associated ER stress by regulating SIRT-1/SREBP-1c axis

J147 treatment protects against traumatic brain injury by inhibiting neuronal endoplasmic reticulum stress potentially via the AMPK/SREBP-1 pathway

Endoplasmic reticulum (ER) stress is recognized as a crucial contributor to the progression of traumatic brain injury (TBI) and represents a potential target for therapeutic intervention. This study aimed to assess the potential of J147, a novel neurotrophic compound, in alleviating ER stress by modulating related signaling pathways, thereby promoting functional recovery in TBI. To this end, adult mice underwent controlled cortical impact (CCI) injury to induce TBI, followed by oral administration of J147 one-hour post-injury, with daily dosing for 3 to 7 days. Multiple behavioral assessments were conducted over 35 days, revealing a significant, dose-dependent improvement in neurofunctional recovery with J147 treatment. The neuropathological analysis demonstrated reduced acute neurodegeneration (observed at three days through FJC staining), enhanced long-term neuron survival (H&E and Nissl staining), and improved neuroplasticity (Golgi staining) at 35 days post-TBI. At the molecular level, TBIinduced AMP-activated protein kinase (AMPK) dephosphorylation, sterol regulatory element binding protein-1 (SREBP-1) activation, and upregulation of ER stress marker proteins, including phosphorylated eukaryotic initiation factor-2α (p-eIF2a), activating transcription factor 4 (ATF4), and C/EBP homologous protein (CHOP) in perilesional cortex neurons at three days post-injury. Notably, the J147 treatment significantly attenuated AMPK dephosphorylation, SERBP-1 activation, and expression of the ER stress markers. In summary, this study reveals the therapeutic promise of J147 in mitigating secondary brain damage associated with TBI and improving long-term functional recovery by modulating ER stress pathways.

SIRT1/SREBPs-mediated regulation of lipid metabolism

Sirtuins, also called silent information regulator 2, are enzymes that rely on nicotinamide adenine dinucleotide (NAD+) to function as histone deacetylases. Further investigation is warranted to explore the advantageous impacts of Sirtuin 1 (SIRT1), a constituent of the sirtuin group, on lipid metabolism, in addition to its well-researched involvement in extending lifespan. The regulation of gene expression has been extensively linked to SIRT1. Sterol regulatory element-binding protein (SREBP) is a substrate of SIRT1 that has attracted significant interest due to its role in multiple cellular processes including cell cycle regulation, DNA damage repair, and metabolic functions. Hence, the objective of this analysis was to investigate and elucidate the correlation between SIRT1 and SREBPs, as well as assess the contribution of SIRT1/SREBPs in mitigating lipid metabolism dysfunction. The objective of this research was to investigate whether SIRT1 and SREBPs could be utilized as viable targets for therapeutic intervention in managing complications associated with diabetes.

Pancreastatin deteriorates hepatic lipid metabolism via elevating fetuin B in ovariectomized rats

Hepatic steatosis is an important mstetabolic complication in women encountering postmenopausal phase of life. Pancreastatin (PST), has previously been investigated in diabetic and insulin resistant rodents. The present study highlighted the role of PST in ovariectomized rats. Female SD rats were ovariectomized and subsequently fed high fructose diet for 12 weeks. PST inhibitor peptide was intraperitoneally administered for 14 days and further examined for insulin resistance, glucose intolerance development, body mass composition, lipid profile detection and hepatic fibrosis. Gut microbial alterations has also been investigated. Results showed development of glucose intolerance in high fructose fed ovariectomized rats with reduced level of reproductive hormones including estradiol and progesterone. Enhanced lipid production was detected in these rats as they showed increased triglycerides, lipid accumulation in liver tissue (determined by HE staining, Oil Red O staining, Nile Red staining). Sirius Red and Masson's trichome analysis depicted positive results for fibrosis development. We also found gut microbiota alterations in fecal samples of these rats. Furthermore, PST inhibition decreased the expression of hepatic Fetuin B and resumed gut microbial diversity. PST deregulates hepatic lipid metabolism which leads to altered expression of Fetuin B in liver and gut dysbiosis in postmenopausal rats.

SIRT-1 is required for release of enveloped enteroviruses

Enterovirus D68 (EV-D68) is a re-emerging enterovirus that causes acute respiratory illness in infants and has recently been linked to Acute Flaccid Myelitis. Here, we show that the histone deacetylase, SIRT-1, is essential for autophagy and EV-D68 infection. Knockdown of SIRT-1 inhibits autophagy and reduces EV-D68 extracellular titers. The proviral activity of SIRT-1 does not require its deacetylase activity or functional autophagy. SIRT-1's proviral activity is, we demonstrate, mediated through the repression of endoplasmic reticulum stress (ER stress). Inducing ER stress through thapsigargin treatment or SERCA2A knockdown in SIRT-1 knockdown cells had no additional effect on EV-D68 extracellular titers. Knockdown of SIRT-1 also decreases poliovirus and SARS-CoV-2 titers but not coxsackievirus B3. In non-lytic conditions, EV-D68 is primarily released in an enveloped form, and SIRT-1 is required for this process. Our data show that SIRT-1, through its translocation to the cytosol, is critical to promote the release of enveloped EV-D68 viral particles.

Comprehensive assessment of detoxification mechanisms of hydrolysis fish peptides in largemouth bass (Micropterus salmoides) under copper exposure: Tracing from bioaccumulation, oxidative stress, lipid deposition to metabolomics

As a heavy metal, copper is toxic to aquatic organisms in water, causing oxidative stress and lipid deposition. However, there is currently no effective dietary strategy to prevent damage caused by copper exposure. Here, copper bioaccumulation, antioxidant enzymes, lipogenic enzymes, lipid metabolism-related gene expression levels and metabolic pathways were synthesized and evaluated in copper-exposed largemouth bass (Micropterus salmoides) after hydrolysis fish peptides (HFP) pretreatment. The results showed that supplementation with 1% (P < 0.05), 3% (P < 0.01) and 5% (P < 0.05) HFP significantly reduced the copper bioaccumulation in largemouth bass. Hydrolysis fish peptides supplementation significantly reduced the activities of total antioxidant capacity (P < 0.01) and catalase (P < 0.01) and the contents of glutathione (P < 0.01) and malondialdehyde (P < 0.05). Fatty acid synthetase concentration was significantly reduced in fish supplemented with 3% (P < 0.05) and 5% HFP (P < 0.05). Similarly, fish fed 3% (P < 0.05) and 5% (P < 0.01) HFP significantly reduced the glucose-6-phosphate dehydrogenase concentration. Serum metabolomics revealed that 85, 144 and 207 differential metabolites were obtained in fish supplemented with 1%, 3% and 5% HFP, respectively. The differential metabolites were mainly lipids and lipid-like molecules, which were associated with the lipid metabolism pathways. The expression levels of fatty acid synthase (P < 0.01), sterol regulatory element binding protein-1c (P < 0.05), liver X receptor (P < 0.001), peroxisome proliferator activated γ (P < 0.01), apolipoprotein B (P < 0.001) and fatty acid-binding protein 1 (P < 0.01) were significantly down-regulated and the expression levels of carnitine palmitoyltransferase 1α (P < 0.01), hormone-sensitive lipase (P < 0.001), apolipoprotein A 1 (P < 0.05) were significantly up-regulated in fish fed with 3% HFP. Additionally, supplementation with 3% (P < 0.01) and 5% (P < 0.001) HFP significantly up-regulated the expression level of B-cell lymphoma-2 with a dose-dependent effect. In conclusion, our study confirmed that HFP supplementation was closely associated with oxidative stress, enzymatic activities and related pathways of lipid metabolism, and apoptosis, and in general alleviated lipid deposition caused by copper exposure in largemouth bass.

Chromogranin A-derived peptides pancreastatin and catestatin: emerging therapeutic target for diabetes

Chromogranin A (ChgA) is an acidic pro-protein found in neuroendocrine organs, pheochromocytoma chromaffin granules, and tumor cells. Proteolytic processing of ChgA gives rise to an array of biologically active peptides such as pancreastatin (PST), vasostatin, WE14, catestatin (CST), and serpinin, which have diverse roles in regulating cardiovascular functions and metabolism, as well as inflammation. Intricate tissue-specific role of ChgA-derived peptide activity in preclinical rodent models of metabolic syndrome reveals complex effects on carbohydrate and lipid metabolism. Indeed, ChgA-derived peptides, PST and CST, play a pivotal role in metabolic syndrome such as obesity, insulin resistance, and diabetes mellitus. Additionally, supplementation of specific peptide in ChgA-KO mice have an opposing effect on physiological functions, such as PST supplementation reduces insulin sensitivity and enhances inflammatory response. In contrast, CST supplementation enhances insulin sensitivity and reduces inflammatory response. In this review, we focus on the tissue-specific role of PST and CST as therapeutic targets in regulating carbohydrate and lipid metabolism, along with the associated risk factors.

Polyphenolic-rich Cissus quadrangularis extract ameliorates insulin resistance by activating AdipoR1 in peri-/post-menopausal rats

Insulin resistance (IR) is a significant complication in menopausal women, which predisposes them to cardiovascular disorder, obesity, and diabetes. Cissus quadrangularis is a polyphenolic plant rich in nutrients and is used as an edible vegetable in Nigeria. Previously, we investigated that C. quadrangularis extract (EECQ) treatment ameliorates IR, hyperlipidemia, and overweight in diabetic rats. Accordingly, in the current study, we further evaluated the adiponectin mimetic activity of EECQ in peri-/post-menopausal rats. Perimenopause was induced by High-fat diet/4-vinylcyclohexenediepoxide/(HFD-VCD), while postmenopause was by HFD/bilateral ovariectomy (HFD-OVX). Both the menopausal rats demonstrated an abnormal level of sex hormones, IR, hyperlipidemia, increased fat mass, and abnormal weight gain. Nevertheless, EECQ treated group revealed protection from these untoward complications. Furthermore, the docking score of major constituents of EECQ on adiponectin receptor 1 (AdipoR1) depicted a strong binding affinity, which was comparable to the ligand adipoRon. Besides, AdipoR1 expression determined by RT-PCR, Western blotting, and immunohistochemistry was downregulated in peri-/post-menopausal rats. Similarly, the expression of AdipoR1 downstream marker APPL1 and insulin sensitivity markers, including IRS1, Akt1, and GLUT4, were also dysregulated in menopausal rats. However, EECQ treated rats manifested restoration of normal expression of APPL1, IRS1, Akt1, and GLUT4 by upregulating AdipoR1. Altogether, the current study promulgated the adiponectin mimetic activity of EECQ, which is substantial to mitigate IR in menopausal conditions.

Pyrroloquinoline quinone alleviates oxidative damage induced by high glucose in HepG2 cells

Hyperglycemia as a common metabolic disorder in diabetes led to oxidative stress, inflammation and other complications. Natural and manufactured antioxidants alleviates the side effects of diabetes. The purpose of current study is to investigate the effect of pyrroloquinoline quinine (PQQ) as an antioxidant on the content of glucose-induced oxidative stress generation in the cells of the human hepatocellular liver carcinoma (HepG2) by inhibiting advanced glycation end products (AGEs) formation. The HepG2 cells were exposed to high dose (50 mM) of glucose (HG) only and with PQQ (HG + PQQ). Treatment with high dose increased AGEs formation, expression of receptor for advanced glycation endproducts (RAGE), reactive oxygen species ROS production, and oxidative stress markers in treated HepG2 cells. Interestingly, PQQ significantly reduced AGEs formation and (RAGE) expression, ROS formation, and inflammation induced by glucose. In conclusion, PQQ has a potentiail role as an antioxidant to reduce the oxidative damage during hyperglycemia by AGEs inhibition.

Pancreastatin induces hepatic steatosis in type 2 diabetes by impeding mitochondrial functioning

AIMS

Mitochondrial dysfunction is among the key factors for the advancement of hepatic steatosis to NAFLD and NASH. Pancreastatin (PST: human ChgA250-301) is a dysglycemic hormone, previously reported to promote steatosis and inflammation in various animal models of metabolic disorders. Recently, we observed PST deregulates energy expenditure and mitochondrial functioning in perimenopausal rats. In the current study, we aimed to decipher the role of PST instigated altered mitochondrial functioning in hepatic steatosis.

MAIN METHODS

The HepG2 cells were PST exposed and the Chga gene was knocked down using siRNA and lipofectamine. Parallelly, type 2 diabetes (T2D) was developed in C57BL/6 mice by HFD feeding and administered PST inhibitor (PSTi8).

KEY FINDINGS

The PST exposed cells and HFD fed mice depicted: enhanced CHGA expression detected by IF/IHC, WB, and ELISA; dysregulated cellular ROS, mitochondrial ROS, oxygen consumption rate, mitochondrial membrane potential, ATP level, and NADP/NADP ratio; enhanced apoptosis determined by MTT, TUNEL, Annexin-V FITC, and WB of Bax/bcl2 and caspase 3; hepatic lipid accumulation upon Nile Red, Oil Red O, H&E staining, and the expression of SREBP-1c, FAS, ACC, and SCD; inflammation based on expression and circulatory level of IL6, IL-1β, and TNF-α. However, Chga knocked down HepG2 cells and PSTi8 treated mice unveiled protection from all the above abnormalities.

SIGNIFICANCE

Collectively, the aforementioned data suggested the alteration in mitochondrial function induced by PST is responsible for hepatic steatosis in T2D.

Endoplasmic Reticulum Stress in Diabetic Nephrology: Regulation, Pathological Role, and Therapeutic Potential

Recent progress has been made in understanding the roles and mechanisms of endoplasmic reticulum (ER) stress in the development and pathogenesis of diabetic nephropathy (DN). Hyperglycemia induces ER stress and apoptosis in renal cells. The induction of ER stress can be cytoprotective or cytotoxic. Experimental treatment of animals with ER stress inhibitors alleviated renal damage. Considering these findings, the normalization of ER stress by pharmacological agents is a promising approach to prevent or arrest DN progression. The current article reviews the mechanisms, roles, and therapeutic aspects of these findings.

Pancreastatin mediated regulation of UCP-1 and energy expenditure in high fructose fed perimenopausal rats

AIMS

Pancreastatin (PST) is a crucial bioactive peptide derived from chromogranin A (CHGA) proprotein that exhibits an anti-insulin effect on adipocytes. Herein, we investigated the effects of PST on brown adipose tissues (BAT) and white adipose tissue (WAT) in connection with uncoupling protein-1 (UCP-1) regulated energy expenditure in high fructose diet (HFrD) fed and vinylcyclohexenediepoxide (VCD) induced perimenopausal rats.

MATERIAL AND METHODS

We administered VCD in rats for 17 consecutive days and fed HFrd for 12 weeks. After 12 weeks estradiol and progesterone levels were detected. Furthermore, detection of glucose tolerance, insulin sensitivity, and body composition revealed impaired glucose homeostasis and enhanced PST levels. Effects of enhanced PST on UCP-1 level in BAT and WAT of perimenopausal rats were further investigated.

KEY FINDINGS

Reduced serum estradiol, progesterone, and attenuated insulin response confirmed perimenopausal model development. Furthermore, enhanced PST serum level and its increased expression in BAT and WAT downregulated the UCP-1 expression. Subsequently, impaired ATP level, NADP/NADPH ratio, citrate synthase activity, enhanced mitochondrial reactive oxygen species (ROS) generation and perturbed mitochondrial membrane potential, further exacerbated mitochondrial dysfunction, cellular ROS production, and promoted apoptosis. Interestingly, PST inhibition by PST inhibitor peptide-8 (PSTi8) displayed a favorable impact on UCP-1 and energy expenditure.

SIGNIFICANCE

The aforementioned outcomes indicated the substantial role of PST in altering the UCP-1 expression and associated energy homeostasis. Hence our results corroborate novel avenues to unravel the quest deciphering PST's role in energy homeostasis and its association with perimenopause.