Dapagliflozin attenuates steatosis in livers of high-fat diet-induced mice and oleic acid-treated L02 cells via regulating AMPK/mTOR pathway

Empagliflozin and memantine combination ameliorates cognitive impairment in scopolamine + heavy metal mixture-induced Alzheimer's disease in rats: role of AMPK/mTOR, BDNF, BACE-1, neuroinflammation, and oxidative stress

One of the major consequences of diabetes mellitus that has gained attention due to its rising incidence is cognitive impairment. Recent research suggested that sodium-glucose cotransporter-2 (SGLT-2) inhibitors can mitigate memory impairment linked to Alzheimer's disease and are now being explored for their cognitive benefits. However, their mechanisms were not thoroughly studied. This research investigates the hypothesis of the neuroprotective effect of empagliflozin administration against scopolamine-heavy metal mixture (SCO + HMM)-treated Alzheimer's rat models in comparison with memantine as a reference drug and the impact of their combination. Yet, the neuroprotective effects of memantine and empagliflozin combination against cognitive impairment have not been previously explored. This study employed adult male albino rats categorized into five groups. The impact of empagliflozin, memantine, and their concomitant administration on cognitive performance was assessed in a scopolamine and heavy metal mixture-treated Alzheimer's disease model in rats. The assessment of rats' cognitive behavior, memory, and spatial learning was conducted, followed by an evaluation of hippocampal brain-derived neurotrophic factor (BDNF), beta-secretase (BACE-1), oxidative stress (OS), and inflammatory marker activity. And, a western blot analysis was conducted to detect phosphorylated 5' AMP-activated protein kinase (p-AMPK), phosphorylated mammalian target of rapamycin (p-mTOR), and heme oxygenase-1 (HO-1). Hippocampal and cerebellar histopathology were thoroughly examined, in addition to the expressions of amyloid β (Aβ). The current data demonstrate the involvement of the pAMPK/mTOR/HO-1 signaling pathway in empagliflozin neuroprotection against SCO + HMM-induced AD. In addition, it reduces AD hallmarks (Aβ and BACE1), neuro-inflammation, and oxidative stress sequelae, and enhances neurogenesis and synaptic density via BDNF. This study proposes that EMPA, especially when co-administered with other conventional anti-Alzheimer therapy, may be formulated into an innovative therapeutic strategy for the enhancement of cognitive impairments associated with neurodegenerative disorders.

Dapagliflozin modulates hepatic lipid metabolism through the proprotein convertase subtilisin/kexin type 9/low density lipoprotein receptor pathway

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is mainly secreted by the liver, and plays a crucial role in lipid metabolism disorder. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) can regulate lipid metabolism through various pathways, including reducing visceral fat accumulation, modulating serum lipoprotein levels and alleviating hepatic steatosis. However, the specific regulatory mechanisms remain unclear.

METHODS

We built a model of glucose and lipid metabolism disorder in vivo and in vitro, and explored the regulatory mechanism of dapagliflozin in regulating liver lipid metabolism.

RESULTS

We found that the SGLT2i dapagliflozin significantly reduced serum levels of PCSK9, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C) in high-fat diet (HFD)-fed mice, while also improving hepatic steatosis. In vitro studies confirmed that dapagliflozin increased LDL receptor (LDLR) expression in HepG2 cells, enhancing their ability to uptake LDL-C.

CONCLUSIONS

Further mechanistic studies revealed that the hepatocyte nuclear factor-1-alpha (HNF1α)/PCSK9/LDLR signalling pathway may be involved in dapagliflozin's regulation of lipid metabolism homeostasis.

Modulation of AMPK/mTOR Autophagic Pathway Using Dapagliflozin Protects Against Cadmium-Induced Testicular and Renal Injury in Rats

Cadmium is a widely distributed heavy metal found in the environment that poses serious hazards to human health. Dapagliflozin (DAPA), a sodium-glucose co-transporter 2 (SGLT-2) inhibitor, exhibited antioxidant, antiapoptotic, and anti-inflammatory properties. Our data assessed the effect of DAPA against Cd-triggered renal and testicular impairment in rats, as well as the underlying mechanisms. Cd (30 mg/kg) and DAPA (5 and 10 mg/kg) were administrated by oral gavage to rats and continued for 21 days. DAPA attenuated Cd-triggered renal and testicular injury as shown by diminishing serum creatinine, BUN, and urinary total protein concentration in addition to increasing creatinine clearance, urinary creatinine, and serum testosterone. Moreover, it diminished renal and testicular histopathological alterations induced by Cd. DAPA stimulated the impaired autophagy flux as seen by significantly elevating the p-AMPK/total AMPK, decreasing p-mTOR/total mTOR ratios, and diminishing p62 & LC3 protein levels. Additionally, DAPA significantly lowered MDA content, increased GSH level and SOD activity. Moreover, it augmented the cytoprotective Nrf2/HO-1 signaling pathway. Furthermore, it attenuated renal and testicular apoptotic cell death via decreasing caspase-3 expression. Conclusion: Boosting autophagic events and combating oxidative stress and apoptosis by DAPA were engaged in alleviating Cd-induced renal and testicular impairment. This was accomplished by modulating the AMPK/mTOR and enhancing the Nrf2/HO-1 pathways.

Dapagliflozin attenuates metabolic dysfunction-associated steatotic liver disease by inhibiting lipid accumulation, inflammation and liver fibrosis

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as a globally prevalent liver disease, closely linked to the rising incidence of obesity, diabetes, and metabolic syndrome. Dapagliflozin (DaPa), a sodium-glucose cotransporter-2 inhibitor, is primarily prescribed for diabetes management. It has shown potential efficacy in managing MASLD in clinical settings. However, the molecular mechanisms underlying the effects of DaPa on MASLD remain poorly understood. Hence, we aimed to investigate the role of and mechanisms underlying DaPa in MASLD.

METHODS

Male diet-induced obese (DIO) C57BL/6J mice were injected with streptozotocin (STZ), followed by a high-fat diet regimen to stimulate metabolic dysfunction. Subsequently, they received DaPa via gavage for 5 weeks. Hepatic lipid accumulation, pathological alterations, inflammatory markers, and liver fibrosis were assessed.

RESULTS

DaPa administration reduced liver fat accumulation in DIO mice. Additionally, it decreased oxidative stress and lipid peroxide levels, which was attributed to the upregulation of glutathione and the downregulation of malondialdehyde and reactive oxygen species levels. Notably, DaPa downregulated the inflammatory response and reduced liver fibrosis.

CONCLUSIONS

DaPa protects against MASLD by inhibiting lipid accumulation, inflammation, oxidative stress, and liver fibrosis.

Current Therapeutic Landscape for Metabolic Dysfunction-Associated Steatohepatitis

In recent years, "metabolic dysfunction-associated steatotic liver disease" (MASLD) has been proposed to better connect liver disease to metabolic dysfunction, which is the most common chronic liver disease worldwide. MASLD affects more than 30% of individuals globally, and it is diagnosed by the combination of hepatic steatosis and obesity, type 2 diabetes, or two metabolic risk factors. MASLD begins with the buildup of extra fat, often greater than 5%, within the liver, causing liver hepatocytes to become stressed. This can proceed to a more severe form, metabolic dysfunction-associated steatohepatitis (MASH), in 20-30% of people, where inflammation in the liver causes tissue fibrosis, which limits blood flow over time. As fibrosis worsens, MASH may lead to cirrhosis, liver failure, or even liver cancer. While the pathophysiology of MASLD is not fully known, the current "multiple-hits" concept proposes that dietary and lifestyle factors, metabolic factors, and genetic or epigenetic factors contribute to elevated oxidative stress and inflammation, causing liver fibrosis. This review article provides an overview of the pathogenesis of MASLD and evaluates existing therapies as well as pharmacological drugs that are currently being studied in clinical trials for MASLD or MASH.

Chiglitazar attenuates high-fat diet-induced nonalcoholic fatty liver disease by modulating multiple pathways in mice

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide; however, effective intervention strategies for NAFLD are still unavailable. The present study sought to investigate the efficacy of chiglitazar, a pan-PPAR agonist, in protecting against NAFLD in mice and its underlying molecular mechanism. Male C57BL/6 J mice were fed a high-fat diet (HFD) for 8 weeks to generate NAFLD and the HFD was continued for an additional 10 weeks in the absence or presence of 5 mg/kg/d or 10 mg/kg/d chiglitazar by gavage. Chiglitazar significantly improved dyslipidemia and insulin resistance, ameliorated hepatic steatosis and reduced liver inflammation and oxidative stress in NAFLD mice. RNA-seq revealed that chiglitazar alleviated HFD-induced NAFLD in mice through multiple pathways, including fatty acid metabolism regulation, insulin signaling pathway, and AMPK signaling pathway. This study demonstrated the potential therapeutic effect of chiglitazar on NAFLD. Chiglitazar ameliorated NAFLD by modulating multiple pathways.

Efficacy and mechanism of action of Yanxiao Di'naer formula for non-alcoholic steatohepatitis treatment based on metabolomics and RNA sequencing

ETHNOPHARMACOLOGICAL RELEVANCE

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide. Nonalcoholic steatohepatitis (NASH) is a crucial component of this disease spectrum. The Yanxiao Di'naer formula (YXDNE) is an Uyghur medical extract that has been used in folk medicine to treat hepatitis for a long time. However, the role and mechanism of action of YXDNE in NASH treatment remains unclear.

OBJECTIVE

The objective of this study was to assess the effectiveness of YXDNE in treating NASH induced by injections of carbon tetrachloride combined with a high-fat high-cholesterol diet (HFHCD), and to clarify the underlying mechanisms.

METHODS

The compounds in the YXDNE extract were analysed for classification and proportions using ultra-performance liquid chromatography-mass spectrometry. The efficacy of YXDNE in treating abnormal lipid metabolism was evaluated in L02 cells in vitro. In addition, a C57BL/6 mouse model of NASH was established to evaluate the therapeutic efficacy of YXDNE in vivo. Metabolomics and RNA sequencing were used to analyse the therapeutic effects of YXDNE on the liver. The corresponding signalling pathways were found to target AMPKα1, PPARα, and NF-κB. The efficacy of YXDNE was validated using inhibitors or silencing RNA (siRNA) against AMPKα1 and PPARα.

RESULTS

This study confirmed that YXDNE treatment ameliorated NASH in a murine model of this disease. Metabolomics analysis suggested that YXDNE efficacy was associated with fatty acid catabolism and AMPK signalling pathways. RNA sequencing results showed that YXDNE efficacy in treating NASH was highly correlated with the AMPK, PPARα and NF-κB pathways. Both in vitro and in vivo experimental data demonstrated that YXDNE affected the expression of p-AMPKα1, PPARα, p-NF-κB, IκB, and p-IκB. The efficacy of YXDNE in treating NASH in vitro was cancelled when AMPK was inhibited with Compound C or PPARα was modulated via siRNA.

CONCLUSIONS

YXDNE may have a therapeutic effect on abnormal lipid metabolism in L02 cells and in a murine model of NASH by affecting the AMPKα1/PPARα/NF-κB signalling pathway. Therefore, YXDNE has the potential for clinical application in the prevention and treatment of NASH.

Dapagliflozin: A Promising Strategy to Combat Cisplatin-Induced Hepatotoxicity in Wistar Rats

Recognizing the challenges posed by chemotherapy, specifically the hepatotoxic effects of drugs like cisplatin, this study aimed to examine the hepatoprotective potential of dapagliflozin to mitigate cisplatin-induced hepatotoxicity in a rat model. This study focused on repurposing drugs such as dapagliflozin and natural agents like silymarin as potential interventions to address cisplatin-induced hepatotoxicity. Thirty adult female Wistar rats were distributed into five groups and treated with cisplatin alone, silymarin, dapagliflozin, or a combination of dapagliflozin and silymarin accordingly for 45 days. Body weight, fasting blood glucose levels, liver function tests, and histopathological analysis were conducted to evaluate the hepatoprotective effects. Cisplatin-induced hepatotoxicity significantly (p < 0.05) increased the serum levels of ALT, AST, TB, and reduced the TP and albumin levels. Dapagliflozin administration led to significant reductions in ALT, AST, TB, and increased albumin levels. Silymarin demonstrated comparable effects. Combining dapagliflozin and silymarin showed synergistic effects, further reducing the liver enzymes and improving albumin levels. Histopathological examination supported these findings, revealing the restoration of liver structure with dapagliflozin and silymarin treatment. Dapagliflozin and silymarin exhibited substantial hepatoprotective benefits against cisplatin-induced hepatotoxicity in rats. The combination therapy demonstrated synergistic effects, highlighting a potential therapeutic approach for mitigating chemotherapy-induced liver damage. Further research into molecular mechanisms and clinical translation is warranted, offering hope for improved clinical outcomes in cancer patients undergoing cisplatin-based chemotherapy.

Unlocking Synergistic Hepatoprotection: Dapagliflozin and Silymarin Combination Therapy Modulates Nuclear Erythroid 2-Related Factor 2/Heme Oxygenase-1 Pathway in Carbon Tetrachloride-Induced Hepatotoxicity in Wistar Rats

This study was aimed to investigate the hepatoprotective potential of dapagliflozin and silymarin alone and in combination to combat carbon tetrachloride (CCl4)-induced hepatotoxicity and the anticipated mechanisms. Thirty female Wistar rats were randomly allocated into five different groups. All the experimental animals except the normal control (Group I) were administered CCl4. Additionally, Groups II, III, IV, and V were treated with gum acacia, silymarin, dapagliflozin, and a combination of dapagliflozin and silymarin, respectively, for 14 days. Dapagliflozin, silymarin alone, and in combination, significantly reduced (p < 0.05) serum levels of ALT, AST, AST:ALT ratio, and total bilirubin compared to CCl4-intoxicated control rats. There was a notable reduction (p < 0.05) observed in the levels of IL-1beta, IL-6, TNF-alpha, nitrites, and 4-hydroxynonenal, accompanied by an elevation in catalase, superoxide dismutase, glutathione peroxidase, nuclear erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) in liver homogenates of the groups treated with dapagliflozin, silymarin alone, and in combination, as compared to the CCl4-intoxicated control group. Dapagliflozin in combination with silymarin showed a synergistic hepatoprotective effect. Our study reveals the profound hepatoprotective potential of dapagliflozin alone and in combination with silymarin in CCl4-intoxicated Wistar rats by modulating the Nrf2 and HO-1 signaling pathways.

Glucose uptake in trophoblasts of GDM mice is regulated by the AMPK-CLUT3 signaling pathway

GDM, as a metabolic disease during pregnancy, regulates GLUT3 translocation by AMPK, thereby affecting glucose uptake in trophoblasts. It provides a new research idea and therapeutic target for alleviating intrauterine hyperglycemia in GDM. STZ was used to construct GDM mice, inject AICAR into pregnant mice, and observe fetal and placental weight; flow cytometry was employed for the detection of glucose uptake by primary trophoblast cells; immunofluorescence was applied to detect the localization of GLUT3 and AMPK in placental tissue; Cocofal microscope was used to detect the localization of GLUT3 in trophoblast cells;qRT-PCR and Western blot experiments were carried out to detect the expression levels of GLUT3 and AMPK in placental tissue; CO-IP was utilized to detect the interaction of GLUT3 and AMPK. Compared with the normal pregnancy group, the weight of the fetus and placenta of GDM mice increased (P < 0.001), and the ability of trophoblasts to take up glucose decreased (P < 0.001). In addition, AMPK activity in trophoblasts and membrane localization of GLUT3 in GDM mice were down-regulated compared with normal pregnant mice (P < 0.05). There is an interaction between GLUT3 and AMPK. Activating AMPK in trophoblasts can up-regulate the expression of GLUT3 membrane protein in trophoblasts of mice (P < 0.05) and increase the glucose uptake of trophoblasts (P < 0.05). We speculate that inhibition of AMPK activity in GDM mice results in aberrant localization of GLUT3, which in turn attenuates glucose uptake by placental trophoblast cells. AICAR activates AMPK to increase the membrane localization of GLUT3 and improve the glucose uptake capacity of trophoblasts.

Dapagliflozin ameliorates hepatic steatosis via suppressing LXRα-mediated synthesis of lipids and bile acids

Nonalcoholic fatty liver disease (NAFLD) prevalence is rising globally with no pharmacotherapies approved. Hepatic steatosis is closely associated with progression and prognosis of NAFLD. Dapagliflozin, kind of sodium-glucose cotransporter 2 (SGLT2) inhibitor, was found to improve NAFLD in clinical trials, while the underlying mechanism remains poorly elucidated. Here, we reported that dapagliflozin effectively mitigated liver injury and relieved lipid metabolism disorders in vivo. Further investigation showed that dapagliflozin markedly suppressed Liver X Receptor α (LXRα)-mediated synthesis of de novo lipids and bile acids (BAs). In AML12 cells, our results proved dapagliflozin decreased lipid contents via inhibiting the expression of LXRα and downstream liposynthesis genes. Proteosome inhibitor MG132 eliminated the effect of dapagliflozin on LXRα-mediated signaling pathway, which suggested that dapagliflozin downregulated LXRα expression through increasing LXRα degradation. Knockdown of LXRα with siRNA abolished the reduction of lipogenesis from dapagliflozin treatment, indicating that LXRα might be the pivotal target for dapagliflozin to exhibit the aforementioned benefits. Furthermore, the data showed that dapagliflozin reversed gut dysbiosis induced by BAs disruption and altered gut microbiota profile to reduce intestinal lipids absorption. Together, our study deciphered a novel mechanism by which dapagliflozin relieved hepatic steatosis and highlighted the potential benefit of dapagliflozin in treating NAFLD.

Dapagliflozin promotes browning of white adipose tissue through the FGFR1-LKB1-AMPK signaling pathway

BACKGROUND

Obesity is associated with a wide variety of metabolic disorders that impose significant burdens on patients and society. The "browning" phenomenon in white adipose tissue (WAT) has emerged as a promising therapeutic strategy to combat metabolic disturbances. However, though the anti-diabetic drug dapagliflozin (DAPA) is thought to promote "browning," the specific mechanism of this was previously unclear.

METHODS

In this study, C57BL/6 J male mice were used to establish an obesity model by high-fat diet feeding, and 3T3-L1 cells were used to induce mature adipocytes and to explore the role and mechanism of DAPA in "browning" through a combination of in vitro and in vivo experiments.

RESULTS

The results show that DAPA promotes WAT "browning" and improves metabolic disorders. Furthermore, we discovered that DAPA activated "browning" through the fibroblast growth factor receptors 1-liver kinase B1-adenosine monophosphate-activated protein kinase signaling pathway.

CONCLUSION

These findings provide a rational basis for the use of DAPA in treating obesity by promoting the browning of white adipose tissue.

Effects of NPY-2 Receptor Antagonists, Semaglutide, PYY3-36, and Empagliflozin on Early MASLD in Diet-Induced Obese Rats

(1) Background: Modulators of the Neuropeptide Y (NPY) system are involved in energy metabolism, but the effect of NPY receptor antagonists on metabolic-dysfunction-associated steatotic liver disease (MASLD), a common obesity-related comorbidity, are largely unknown. In this study, we report on the effects of antagonists of the NPY-2 receptor (Y2R) in comparison with empagliflozin and semaglutide, substances that are known to be beneficial in MASLD. (2) Methods: Diet-induced obese (DIO) male Wistar rats were randomized into the following treatment groups: empagliflozin, semaglutide ± PYY3-36, the Y2R antagonists JNJ 31020028 and a food-restricted group, as well as a control group. After a treatment period of 8 weeks, livers were weighed and histologically evaluated. QrtPCR was performed to investigate liver inflammation and de novo lipogenesis (in liver and adipose tissue). Serum samples were analysed for metabolic parameters. (3) Results: Semaglutide + PYY3-36 led to significant weight loss, reduced liver steatosis (p = 0.05), and decreased inflammation, insulin resistance, and leptin levels. JNJ-31020028 prevented steatosis (p = 0.03) without significant weight loss. Hepatic downregulation of de novo lipogenesis-regulating genes (SREBP1 and MLXIPL) was observed in JNJ-31020028-treated rats (p ≤ 0.0001). Food restriction also resulted in significantly reduced weight, steatosis, and hepatic de novo lipogenesis. (4) Conclusions: Body weight reduction (e.g., by food restriction or drugs like semaglutide ± PYY3-36) is effective in improving liver steatosis in DIO rats. Remarkably, the body-weight-neutral Y2R antagonists may be effective in preventing liver steatosis through a reduction in de novo lipogenesis, making this drug class a candidate for the treatment of (early) MASLD.

Fisetin, a dietary flavonoid, promotes transintestinal cholesterol excretion through the activation of PPARδ

Fisetin, a dietary polyphenol abundantly found in strawberries, exhibits a broad spectrum of health-promoting activities, including antihyperlipidemic effects. This study aimed to investigate the regulatory effect of fisetin on cholesterol elimination through novel transintestinal cholesterol excretion (TICE) pathway. A hypercholesterolemic mouse model and human colon epithelial cancer cell line Caco-2 were utilized to conduct the study. In hypercholesterolemic mice, fisetin (25 mg/kg) treatment reduced serum total cholesterol by 46.48% and significantly decreased lipid accumulation in the liver. Furthermore, fisetin administration led to a substantial increase in the fecal neutral sterol contents, including coprostanol, coprostanone, dihydrocholesterol, and cholesterol. Specifically, these sterol contents increased by approximately 224.20%, 151.40%, 70.40% and 50.72% respectively. The fluorescence intensity of 22-NBD-cholesterol in intestinal perfusion increased by 95.94% in fisetin group (25 mg/kg), indicating that fisetin stimulated TICE. In high cholesterol-induced Caco-2 cells, fisetin at a concentration of 30 μM reduced total cholesterol and free cholesterol by 37.21% and 45.30% respectively, stimulated cholesterol excretion, and inhibited cholesterol accumulation. Additionally, fisetin upregulated the gene and protein expression of cholesterol efflux transporters ABCG5/G8 and ABCB1, while downregulating the cholesterol uptake regulator NPC1L1. Furthermore, fisetin increased LDLR protein expression and decreased PCSK9 expression. Notably, fisetin significantly activated nuclear receptor PPARδ in Caco-2 cells. PPARδ antagonist pretreatment counteracted the regulatory effects of fisetin on TICE regulators, suggesting fisetin lowered cholesterol through enhancing TICE by activation of intestinal PPARδ. Fisetin could be used as functional dietarysupplement for eliminating cholesterol and reducing the incidence of cardiovascular diseases.

Current Treatment Options, Including Diet, Exercise, and Medications: The Impact on Histology

Paralleling the rise in obesity and diabetes, nonalcoholic fatty liver disease (NAFLD) is now the most prevalent chronic liver disease worldwide. Nonalcoholic steatohepatitis (NASH), the progressive form of NAFLD, may progress to cirrhosis, hepatic decompensation, and hepatocellular carcinoma. Despite its public health treat, no approved pharmacotherapies for NAFLD/NASH currently exist. Although the armamentarium of therapies for NASH is limited, current treatment options include life-style modification and the use of medications to treat metabolic comorbidities. This review addresses current approaches to the treatment of NAFLD/NASH, including the impact of diet, exercise, and available pharmacotherapies on the histologic features of liver injury.

Current, emerging, and potential therapies for non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) has been identified as the most common chronic liver disease worldwide, with a growing incidence. NAFLD is considered the hepatic manifestation of a metabolic syndrome that emerges from multiple factors (e.g., oxidative stress, metabolic disorders, endoplasmic reticulum stress, cell death, and inflammation). Non-alcoholic steatohepatitis (NASH), an advanced form of NAFLD, has been reported to be a leading cause of cirrhosis and hepatic carcinoma, and it is progressing rapidly. Since there is no approved pharmacotherapy for NASH, a considerable number of therapeutic targets have emerged with the deepening of the research on NASH pathogenesis. In this study, the therapeutic potential and properties of regulating metabolism, the gut microbiome, antioxidant, microRNA, inhibiting apoptosis, targeting ferroptosis, and stem cell-based therapy in NASH are reviewed and evaluated. Since the single-drug treatment of NASH is affected by individual heterogeneous responses and side effects, it is imperative to precisely carry out targeted therapy with low toxicity. Lastly, targeted therapeutic agent delivery based on exosomes is proposed in this study, such that drugs with different mechanisms can be incorporated to generate high-efficiency and low-toxicity individualized medicine.

Dapagliflozin as an autophagic enhancer via LKB1/AMPK/SIRT1 pathway in ovariectomized/D-galactose Alzheimer's rat model

Autophagy and mitochondrial deficits are characteristics of early phase of Alzheimer's disease (AD). Sodium-glucose cotransporter-2 inhibitors have been nominated as a promising class against AD hallmarks. However, there are no available data yet to discuss the impact of gliflozins on autophagic pathways in AD. Peripherally, dapagliflozin's (DAPA) effect is mostly owed to autophagic signals. Thus, the goal of this study is to screen the power of DAPA centrally on LKB1/AMPK/SIRT1/mTOR signaling in the ovariectomized/D-galactose (OVX/D-Gal) rat model. Animals were arbitrarily distributed between 5 groups; the first group undergone sham operation, while remaining groups undergone OVX followed by D-Gal (150 mg/kg/day; i.p.) for 70 days. After 6 weeks, the third, fourth, and fifth groups received DAPA (1 mg/kg/day; p.o.); concomitantly with the AMPK inhibitor dorsomorphin (DORSO, 25 µg/rat, i.v.) in the fourth group and the SIRT1 inhibitor EX-527 (10 µg/rat, i.v.) in the fifth group. DAPA mitigated cognitive deficits of OVX/D-Gal rats, as mirrored in neurobehavioral task with hippocampal histopathological examination and immunohistochemical aggregates of p-Tau. The neuroprotective effect of DAPA was manifested by elevation of energy sensors; AMP/ATP ratio and LKB1/AMPK protein expressions along with autophagic markers; SIRT1, Beclin1, and LC3B expressions. Downstream the latter, DAPA boosted mTOR and mitochondrial function; TFAM, in contrary lessened BACE1. Herein, DORSO or EX-527 co-administration prohibited DAPA's actions where DORSO elucidated DAPA's direct effect on LKB1 while EX-527 mirrored its indirect effect on SIRT1. Therefore, DAPA implied its anti-AD effect, at least in part, via boosting hippocampal LKB1/AMPK/SIRT1/mTOR signaling in OVX/D-Gal rat model.

Critical Reanalysis of the Mechanisms Underlying the Cardiorenal Benefits of SGLT2 Inhibitors and Reaffirmation of the Nutrient Deprivation Signaling/Autophagy Hypothesis

SGLT2 (sodium-glucose cotransporter 2) inhibitors produce a distinctive pattern of benefits on the evolution and progression of cardiomyopathy and nephropathy, which is characterized by a reduction in oxidative and endoplasmic reticulum stress, restoration of mitochondrial health and enhanced mitochondrial biogenesis, a decrease in proinflammatory and profibrotic pathways, and preservation of cellular and organ integrity and viability. A substantial body of evidence indicates that this characteristic pattern of responses can be explained by the action of SGLT2 inhibitors to promote cellular housekeeping by enhancing autophagic flux, an effect that may be related to the action of these drugs to produce simultaneous upregulation of nutrient deprivation signaling and downregulation of nutrient surplus signaling, as manifested by an increase in the expression and activity of AMPK (adenosine monophosphate-activated protein kinase), SIRT1 (sirtuin 1), SIRT3 (sirtuin 3), SIRT6 (sirtuin 6), and PGC1-α (peroxisome proliferator-activated receptor γ coactivator 1-α) and decreased activation of mTOR (mammalian target of rapamycin). The distinctive pattern of cardioprotective and renoprotective effects of SGLT2 inhibitors is abolished by specific inhibition or knockdown of autophagy, AMPK, and sirtuins. In the clinical setting, the pattern of differentially increased proteins identified in proteomics analyses of blood collected in randomized trials is consistent with these findings. Clinical studies have also shown that SGLT2 inhibitors promote gluconeogenesis, ketogenesis, and erythrocytosis and reduce uricemia, the hallmarks of nutrient deprivation signaling and the principal statistical mediators of the ability of SGLT2 inhibitors to reduce the risk of heart failure and serious renal events. The action of SGLT2 inhibitors to augment autophagic flux is seen in isolated cells and tissues that do not express SGLT2 and are not exposed to changes in environmental glucose or ketones and may be related to an ability of these drugs to bind directly to sirtuins or mTOR. Changes in renal or cardiovascular physiology or metabolism cannot explain the benefits of SGLT2 inhibitors either experimentally or clinically. The direct molecular effects of SGLT2 inhibitors in isolated cells are consistent with the concept that SGLT2 acts as a nutrient surplus sensor, and thus, its inhibition causes enhanced nutrient deprivation signaling and its attendant cytoprotective effects, which can be abolished by specific inhibition or knockdown of AMPK, sirtuins, and autophagic flux.

Interplay between metabolic dysfunction-associated fatty liver disease and chronic kidney disease: Epidemiology, pathophysiologic mechanisms, and treatment considerations

The recently proposed nomenclature change from non-alcoholic fatty liver disease to metabolic dysfunction-associated fatty liver disease (MAFLD) has resulted in the reappraisal of epidemiological trends and associations with other chronic diseases. In this context, MAFLD appears to be tightly linked to incident chronic kidney disease (CKD). This association may be attributed to multiple shared risk factors including type 2 diabetes mellitus, arterial hypertension, obesity, dyslipidemia, and insulin resistance. Moreover, similarities in their molecular pathophysiologic mechanisms can be detected, since inflammation, oxidative stress, fibrosis, and gut dysbiosis are highly prevalent in these pathologic states. At the same time, lines of evidence suggest a genetic predisposition to MAFLD due to gene polymorphisms, such as the PNPLA3 rs738409 G allele polymorphism, which may also propagate renal dysfunction. Concerning their management, available treatment considerations for obesity (bariatric surgery) and novel antidiabetic agents (glucagon-like peptide 1 receptor agonists, sodium-glucose co-transporter 2 inhibitors) appear beneficial in preclinical and clinical studies of MAFLD and CKD modeling. Moreover, alternative approaches such as melatonin supplementation, farnesoid X receptor agonists, and gut microbiota modulation may represent attractive options in the future. With a look to the future, additional adequately sized studies are required, focusing on preventing renal complications in patients with MAFLD and the appropriate management of individuals with concomitant MAFLD and CKD.

Empagliflozin-Enhanced Antioxidant Defense Attenuates Lipotoxicity and Protects Hepatocytes by Promoting FoxO3a- and Nrf2-Mediated Nuclear Translocation via the CAMKK2/AMPK Pathway

Lipotoxicity is an important factor in the development and progression of nonalcoholic steatohepatitis. Excessive accumulation of saturated fatty acids can increase the substrates of the mitochondrial electron transport chain in hepatocytes and cause the generation of reactive oxygen species, resulting in oxidative stress, mitochondrial dysfunction, loss of mitochondrial membrane potential, impaired triphosphate (ATP) production, and fracture and fragmentation of mitochondria, which ultimately leads to hepatocellular inflammatory injuries, apoptosis, and necrosis. In this study, we systematically investigated the effects and molecular mechanisms of empagliflozin on lipotoxicity in palmitic acid-treated LO2 cell lines. We found that empagliflozin protected hepatocytes and inhibited palmitic acid-induced lipotoxicity by reducing oxidative stress, improving mitochondrial functions, and attenuating apoptosis and inflammation responses. The mechanistic study indicated that empagliflozin significantly activated adenosine 5'-monophosphate (AMP)-activated protein kinase alpha (AMPKα) through Calcium/Calmodulin dependent protein kinase kinase beta (CAMKK2) instead of liver kinase B1 (LKB1) or TGF-beta activated kinase (TAK1). The activation of empagliflozin on AMPKα not only promoted FoxO3a phosphorylation and thus forkhead box O 3a (FoxO3a) nuclear translocation, but also promoted Nrf2 nuclear translocation. Furthermore, empagliflozin significantly upregulated the expressions of antioxidant enzymes superoxide dismutase (SOD) and HO-1. In addition, empagliflozin did not attenuate lipid accumulation at all. These results indicated that empagliflozin mitigated lipotoxicity in saturated fatty acid-induced hepatocytes, likely by promoting antioxidant defense instead of attenuating lipid accumulation through enhanced FoxO3a and Nrf2 nuclear translocation dependent on the CAMKK2/AMPKα pathway. The CAMKK2/AMPKα pathway might serve as a promising target in treatment of lipotoxicity in nonalcoholic steatohepatitis.

SGLT-2 Inhibitors in NAFLD: Expanding Their Role beyond Diabetes and Cardioprotection

Non-alcoholic fatty liver disease (NAFLD) is an ‘umbrella’ term, comprising a spectrum ranging from benign, liver steatosis to non-alcoholic steatohepatitis, liver fibrosis and eventually cirrhosis and hepatocellular carcinoma. NAFLD has evolved as a major health problem in recent years. Discovering ways to prevent or delay the progression of NAFLD has become a global focus. Lifestyle modifications remain the cornerstone of NAFLD treatment, even though various pharmaceutical interventions are currently under clinical trial. Among them, sodium-glucose co-transporter type-2 inhibitors (SGLT-2i) are emerging as promising agents. Processes regulated by SGLT-2i, such as endoplasmic reticulum (ER) and oxidative stress, low-grade inflammation, autophagy and apoptosis are all implicated in NAFLD pathogenesis. In this review, we summarize the current understanding of the NAFLD pathophysiology, and specifically focus on the potential impact of SGLT-2i in NAFLD development and progression, providing current evidence from in vitro, animal and human studies. Given this evidence, further mechanistic studies would advance our understanding of the exact mechanisms underlying the pathogenesis of NAFLD and the potential beneficial actions of SGLT-2i in the context of NAFLD treatment.

Differential effect of canagliflozin, a sodium-glucose cotransporter 2 (SGLT2) inhibitor, on slow and fast skeletal muscles from nondiabetic mice

There has been a concern that sodium–glucose cotransporter 2 (SGLT2) inhibitors could reduce skeletal muscle mass and function. Here, we examine the effect of canagliflozin (CANA), an SGLT2 inhibitor, on slow and fast muscles from nondiabetic C57BL/6J mice. In this study, mice were fed with or without CANA under ad libitum feeding, and then evaluated for metabolic valuables as well as slow and fast muscle mass and function. We also examined the effect of CANA on gene expressions and metabolites in slow and fast muscles. During SGLT2 inhibition, fast muscle function is increased, as accompanied by increased food intake, whereas slow muscle function is unaffected, although slow and fast muscle mass is maintained. When the amount of food in CANA-treated mice is adjusted to that in vehicle-treated mice, fast muscle mass and function are reduced, but slow muscle was unaffected during SGLT2 inhibition. In metabolome analysis, glycolytic metabolites and ATP are increased in fast muscle, whereas glycolytic metabolites are reduced but ATP is maintained in slow muscle during SGLT2 inhibition. Amino acids and free fatty acids are increased in slow muscle, but unchanged in fast muscle during SGLT2 inhibition. The metabolic effects on slow and fast muscles are exaggerated when food intake is restricted. This study demonstrates the differential effects of an SGLT2 inhibitor on slow and fast muscles independent of impaired glucose metabolism, thereby providing new insights into how they should be used in patients with diabetes, who are at a high risk of sarcopenia.