The diabetes medication canagliflozin promotes mitochondrial remodelling of adipocyte via the AMPK-Sirt1-Pgc-1α signalling pathway

Rethinking fat Browning: Uncovering new molecular insights into the synergistic roles of fasting, exercise, and cold exposure

The global obesity epidemic highlights the need to understand the molecular mechanisms that regulate energy metabolism. Among emerging research areas, fat browning-the transformation of white adipose tissue into beige fat-has gained significant attention. This review explores the molecular pathways involved in fat browning triggered by fasting, physical exercise, and cold exposure, emphasizing both shared and distinct regulatory mechanisms. These stimuli consistently induce physiological responses such as lipolysis, mitochondrial biogenesis, and improved insulin sensitivity. Notably, PGC-1α and SIRT3 are upregulated across all three conditions, underscoring their central roles in mitochondrial function and energy metabolism and identifying them as promising therapeutic targets. In contrast, UCP1 and PRDM16 exhibit condition-specific regulation, suggesting they may not be universally essential for fat browning. In addition, the review discusses species-specific differences in brown adipose tissue (BAT) activation, particularly between rodents and humans, highlighting the challenges of translating animal model findings to human therapies. Future research should aim to develop selective pharmacological activators of PGC-1α and SIRT3 to enhance therapeutic outcomes while minimizing adverse effects. This review also proposes that integrating fasting, exercise, and cold exposure could provide innovative strategies to promote metabolic health.

Exploring the cognitive impacts of diabetic neuropathy: a comprehensive review

Diabetic neuropathy (DPN) is known to affect various aspects of health, including cognitive function. This study explores how DPN influences cognitive performance and examines the interplay between DPN, gender differences, Alzheimer's Disease (AD), and the socioeconomic burden of neuropathic pain. The research involved a comprehensive review and analysis of 55 studies focusing on cognitive function in diabetic patients with and without DPN. Various cognitive assessments, including memory, processing speed, and olfactory function, were used to evaluate cognitive performance. Gender differences were analyzed in the context of cognitive impairment and neuropathic pain. Additionally, the relationship between peripheral neuropathy and AD was investigated through measures of nerve conduction velocities and amyloid protein deposits. The impact of physical and psychological factors on neuropathic pain and cognitive function was also examined. The findings indicate that diabetic patients with DPN exhibit more severe cognitive impairments compared to those without DPN and healthy controls. Cognitive deficits were particularly notable in memory and processing speed. Gender differences revealed that women with DPN experience more pronounced cognitive dysfunction and a higher incidence of painful neuropathy compared to men. Analysis of peripheral nerve conduction velocities and amyloid deposits suggested a link between neuropathy and AD. Furthermore, poor glycemic control emerged as a critical factor affecting both neuropathy and cognitive function. Psychological distress and socioeconomic factors were found to significantly influence the management and outcomes of neuropathic pain. The study underscores the complex interaction between DPN and cognitive impairment, highlighting the importance of integrated diagnostic and therapeutic approaches. The pronounced cognitive deficits in women and the link between DPN and AD emphasize the need for gender-specific and multifaceted treatment strategies. The socioeconomic impact of neuropathic pain and the role of psychological factors in exacerbating pain and cognitive decline suggest that comprehensive management plans should address both physical and mental health aspects to improve overall patient outcomes.

The Impact of Exercise Training on the Brain and Cognition in Type 2 Diabetes, and its Physiological Mediators: A Systematic Review

BACKGROUND

Type 2 diabetes (T2DM) affects brain structure and function, and is associated with an increased risk of dementia and mild cognitive impairment. It is known that exercise training has a beneficial effect on cognition and brain structure and function, at least in healthy people, but the impact of exercise training on these aspects remains to be fully elucidated in patients with T2DM.

OBJECTIVE

To determine the impact of exercise training on cognition and brain structure and function in T2DM, and identify the involved physiological mediators.

METHODS

This paper systematically reviews studies that evaluate the effect of exercise training on cognition in T2DM, and aims to indicate the most beneficial exercise modality for improving or preserving cognition in this patient group. In addition, the possible physiological mediators and targets involved in these improvements are narratively described in the second part of this review. Papers published up until the 14th of January 2025 were searched by means of the electronic databases PubMed, Embase, and Web of Science. Studies directly investigating the effect of any kind of exercise training on the brain or cognition in patients with T2DM, or animal models thereof, were included, with the exception of human studies assessing cognition only at one time point, and studies combining exercise training with other interventions (e.g. dietary changes, cognitive training, etc.). Study quality was assessed by means of the TESTEX tool for human studies, and the CAMARADES tool for animal studies.

RESULTS

For the systematic part of the review, 22 papers were found to be eligible. 18 out of 22 papers (81.8%) showed a significant positive effect of exercise training on cognition in T2DM, of which two studies only showed significant improvements in the minority of the cognitive tests. Four papers (18.2%) could not find a significant effect of exercise on cognition in T2DM. Resistance and endurance exercise were found to be equally effective for achieving cognitive improvement. Machine-based power training is seemingly more effective than resistance training with body weight and elastic bands to reach cognitive improvement. In addition, BDNF, lactate, leptin, adiponectin, GSK3β, GLP-1, the AMPK/SIRT1 pathway, and the PI3K/Akt pathway were identified as plausible mediators directly from studies investigating the effect of exercise training on brain structure and function in T2DM. Via these mediators, exercise training induces multiple beneficial brain changes, such as increased neuroplasticity, increased insulin sensitivity, and decreased inflammation.

CONCLUSION

Overall, exercise training beneficially affects cognition and brain structure and function in T2DM, with resistance and endurance exercise having similar effects. However, there is a need for additional studies, and more methodological consistency between different studies in order to define an exercise program optimal for improving cognition in T2DM. Furthermore, we were able to define several mediators involved in the effect of exercise training on cognition in T2DM, but further research is necessary to unravel the entire process.

Canagliflozin potentially promotes renal protection against glycerol-induced acute kidney injury by activating the AMPK/SIRT1/FOXO-3a/PGC-1α and Nrf2/HO-1 pathways

The reno-protective potential of canagliflozin (Cana), an inhibitor of the sodium glucose-linked co-transporter-2 (SGLT-2), has been demonstrated in different models of kidney injury. However, its potential role in preventing glycerol (Gly)-induced acute kidney injury (AKI) remains to be divulged. Therefore, the aim of this study is to investigate the potential reno-protective effect of Cana and its underlying mechanism in a rat model of Gly-induced AKI. Rats were randomly allocated into five groups: normal, Gly, Gly pretreated with 10 mg/kg Cana, Gly pretreated with Cana 25 mg/kg, and normal pretreated with Cana 25 mg/kg for 14 consecutive days. Pretreatment with Cana improved renal structure and enhanced kidney functions manifested by reducing serum creatinine and blood urea nitrogen, as well as renal contents of neutrophil gelatinase-associated lipocalin and kidney injury molecule. Moreover, Cana signified its anti-inflammatory effect by reducing the Gly-induced elevation in renal contents of nuclear factor-κB and interleuκin-6. Additionally, Cana augmented the defense enzymatic antioxidants superoxide dismutase (SOD), manganese-SOD, and heme oxygenase-1, besides increasing the protein expression of the antioxidant transcription factor nuclear factor erythroid 2-related factor 2 to point for its ability to correct redox balance. Cana also upregulated the protein expression of the 5' adenosine monophosphate-activated protein kinase (AMPK), Sirtuin1 (SIRT1), Forkhead box protein O3 (FOXO-3a), and peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α), as well as the transcriptional activity of growth arrest and DNA damage-inducible protein alpha (GAAD45a). In conclusion, Cana demonstrated potentially novel reno-protective mechanisms and mitigated the consequences of AKI through its antioxidant and anti-inflammatory properties, partially by activating the AMPK/SIRT1/FOXO-3a/PGC-1α pathway.

CD47-blocking antibody confers metabolic benefits against obesity

CD47-blocking antibody is a well-known potential antibody drug for tumor immunotherapy. However, it is unclear whether CD47-blocking antibody can protect against metabolic disorders. We report that high-fat diet (HFD)-induced obesity increases CD47 expression, while exercise downregulates it in skeletal muscle. Administration of CD47-blocking antibody in mice prevents HFD-induced weight gain and glucose intolerance, enhances exercise capacity, and improves body composition and skeletal muscle mitochondrial function. Mechanistically, the protective effects conferred by CD47-blocking antibody are mediated through activation of AMP-activated protein kinase (AMPK) in skeletal muscle. Consistently, muscle-specific CD47-knockout mice show similar metabolic improvements, indicating a direct muscle-specific role of CD47 in regulating AMPK activation in vivo. Furthermore, the CD47-blocking antibody reduces the phosphorylation of heat shock protein 90α (HSP90α) to activate AMPK in skeletal muscle. In conclusion, CD47-blocking antibody confers metabolic benefits by activating the AMPK pathway in skeletal muscle.

rhCC16 Suppresses Cellular Senescence and Ameliorates COPD-Like Symptoms by Activating the AMPK/Sirt1-PGC-1-α-TFAM Pathway to Promote Mitochondrial Function

Chronic obstructive pulmonary disease (COPD) is a widespread lung disease marked by alveolar wall damage, leading to inflammation and fibrosis. Key risk factors include age, smoking, sex, and education, with smoking being the most crucial. These factors are globally consistent and linked with aging. Club cell secretory protein 16 (CC16), primarily secreted by non-ciliated bronchial epithelial cells, is crucial for pulmonary health, offering anti-inflammatory and antioxidant benefits. CC16 levels are notably reduced in COPD, suggesting its enhancement as a potential treatment. In this study, cellular senescence of BEAS-2B cells was stimulated using cigarette smoke extract (CSE) and the function of recombinant human CC16 protein (rhCC16) in cellular senescence was assessed by detecting the levels of β-galactosidase, p16, p21, ROS and the underlined mechanism was revealed by measuring mitochondrial biogenesis and metabolism. Additionally, COPD mice were prepared, and rhCC16's role on the cellular senescence of lung tissues was examined. Our findings showed that rhCC16 ameliorated cellular senescence in BEAS-2B cells and lung tissues of COPD mice accompanied by lower levels of β-galactosidase, p16, p21 and ROS. Mechanically, rhCC16 mitigated senescence via triggering PGC-1α expression through the AMPK/SIRT1 pathway and fostering mitochondrial biogenesis and metabolism to reduce the levels of ROS. Furthermore, the results also indicated that rhCC16 exerted its effect via both integrin α4β1 and clathrin-mediated endocytosis. Collectively, rhCC16 suppresses cellular senescence and ameliorates COPD-like symptoms by activating the AMPK/Sirt1-PGC-1-α-TFAM pathway to foster mitochondrial function.

Impact of Resveratrol Supplementation on Human Sirtuin 1: A Grading of Recommendations Assessment, Development and Evaluation-Assessed Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Resveratrol, a natural polyphenol compound, possesses anti-aging, antitumor, and vascular protective properties. These attributes are believed to stem from its influence on Sirtuin 1 (Sirt1), a member of the human Sirtuin family and a nicotinamide adenine dinucleotide-dependent histone deacetylase.

OBJECTIVE

The aim of this study was to quantitatively investigate the impact of resveratrol supplementation on Sirt1 levels in adults by conducting a systematic review and meta-analysis of randomized controlled trials (RCTs) involving resveratrol supplementation.

METHODS

This Grading of Recommendations Assessment, Development and Evaluation-assessed systematic review involved a comprehensive search of PubMed, Embase, MEDLINE, Scopus, Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar databases using related keywords and was conducted from March 14, 2024, to April 15, 2024, to identify all RCTs investigating resveratrol's effects on Sirt1. Effect sizes were quantified as mean differences (MDs) or standardized mean differences (SMDs), with standard deviations of outcomes. An overall effect estimate was derived using a random-effects model when 2 or more studies reported similar outcomes. Statistical heterogeneity was assessed through the calculation of I2 statistics. In addition, a dose-response analysis was performed to assess potential dose-response relationships. Risk of bias was assessed using the Cochrane risk-of-bias tool for RCTs (RoB 2). Publication bias was evaluated using Begg's test and a meta-regression using the year of publication as a moderator.

RESULTS

Eleven RCTs examining the effects of resveratrol on Sirt1 gene expression (4 RCTs), protein expression (5 RCTs), and serum levels (3 RCTs) were included in the meta-analysis. The results showed no significant impact of resveratrol on Sirt1 gene expression (SMD = 0.05; 95% CI -0.24 to 0.344; P = .73), protein expression (SMD = 0.3; 95% CI -0.15 to 0.77; P = .18), or serum levels (MD = -0.04; 95% CI -0.235 to 0.16; P = .7). However, subgroup analyses suggested a significant increase in Sirt1 gene expression in studies with an intervention duration of <12 weeks and evaluating blood tissue. Furthermore, the impact of resveratrol on Sirt1 appeared to be influenced by the dosage regimen, with a significant effect for intervention duration.

CONCLUSIONS

Study results indicate that resveratrol supplementation does not significantly influence human Sirt1 based on the overall meta-analysis. However, the dose-response analysis suggests that the effect of resveratrol on Sirt1 depends on the dosage regimen.

Effect of N-Acetylcysteine in Mitochondrial Function, Redox Signaling, and Sirtuin 3 Levels in the Heart During Cardiorenal Syndrome Type 4 Development

Type 4 cardiorenal syndrome (CRS-4) is a pathology in which chronic kidney disease (CKD) triggers the development of cardiovascular disease. CKD pathophysiology produces alterations that can affect the bioenergetics of heart mitochondria, causing oxidative stress and reducing antioxidant glutathione (GSH) levels. GSH depletion alters protein function by affecting post-translational modifications such as S-glutathionylation (RS-SG), exacerbating oxidative stress, and mitochondrial dysfunction. On the other hand, N-acetylcysteine (NAC) is an antioxidant GSH precursor that modulates oxidative stress and RS-SG. Moreover, recent studies have found that NAC can activate the Sirtuin 3 (SIRT3) deacetylase in diseases. However, the role of NAC and its effects on mitochondrial function, redox signaling, and SIRT3 modifications in the heart during CRS-4 have not been studied. This study aimed to investigate the role of NAC in mitochondrial function, redox signaling, and SIRT3 in the hearts of animals with CRS-4 at two months of follow-up. Our results showed that the oral administration of NAC (600 mg/kg/day) improved blood pressure and reduced cardiac fibrosis. NACs' protective effect was associated with preserving cardiac mitochondrial bioenergetics and decreasing these organelles' hydrogen peroxide (H2O2) production. Additionally, NAC increased GSH levels in heart mitochondria and regulated the redox state, which coincided with an increase in nicotinamide adenine dinucleotide oxidized (NAD+) levels and a decrease in mitochondrial acetylated lysines. Finally, NAC increased SIRT3 levels and the activity of superoxide dismutase 2 (SOD-2) in the heart. Thus, treatment with NAC decreases mitochondrial alterations, restores redox signaling, and decreases SIRT3 disturbances during CRS-4 through an antioxidant defense mechanism.

Sodium-glucose co-transporter inhibitors for APOL1 kidney disease: A call for studies

Renal risk variants in the apolipoprotein L1 (APOL1) gene confer protection against trypanosomiasis, but these risk variants (G1 and G2 variants) also predispose to kidney disease among individuals, especially from Sub-SaharanAfrica. Currently, the mechanisms of how these renal risk variants induce kidney damage are not precisely defined, but lysosomal and mitochondrial dysfunction, altered ion channel activity, altered autophagy, and disordered immunity are suggested. Currently, there is no specific treatment for APOL1 kidney disease (APOL1-KD) although several potential disease-specific therapeutic agents are being evaluated in clinical trials. Non-specific interventions include proteinuria screening, salt restriction, and renin-angiotensin-aldosterone system inhibition but are not sufficient to prevent kidney disease progression in APOL1-KD. Given the lack of specific treatment options, more efforts are necessary to reduce kidney disease progression. Sodium glucose co-transport-2 (SGLT2) inhibitors (SGLT2i) are gaining attention for benefits in proteinuric kidney diseases and exert many beneficial effects which theoretically may be beneficial in the context of APOL1-KD. These beneficial effects include but are not limited to increased natriuresis, decreased proteinuria/albuminuria, and mitochondrial dysfunction. SGLT2i have antioxidant, anti-inflammatory and anti-fibrotic effects. In the current review, we highlight the potential reasons for exploring the use of SGLT2i in APOL1-KD. Future studies are warranted to explore if SGLT2i use can provide protection in APOL1-KD.

Combined Treatment of Metformin and Resveratrol Promotes Myogenesis Through Increased Irisin Release in C2C12 Cells

PURPOSE

This study aimed to investigate the additive effects of a combination of metformin and resveratrol on irisin expression in C2C12 cells.

METHODS

The study involved treating C2C12 cells with metformin and resveratrol, either alone or in combination, and analyzing their effects on myogenesis and irisin release. The activation of signaling pathways, including AMPK/SIRT1/PGC1α, as well as the relative mRNA and protein expression levels of MyoD, myogenin, and Myh were also assessed.

RESULTS

Combination treatment with metformin and resveratrol significantly increased MyoD, myogenin, Myh, and FNDC5 expression compared with the group treated with metformin alone. The increase in irisin production was associated with phosphorylation of AMPK and upregulation of PGC-1α and SIRT1, indicating activation of the AMPK/SIRT1/PGC-1α pathway. The mRNA and protein expression levels of MyoD, myogenin, and Myh were also significantly higher in the combination treatment group compared to the metformin alone group.

CONCLUSION

The combination of metformin and resveratrol effectively increased irisin release through the AMPK/Sirt1/PGC-1α pathway, suggesting that this combination treatment could enhance myogenesis.

Dual Roles of Canagliflozin on Cholangiocarcinoma Cell Growth and Enhanced Growth Suppression in Combination with FK866

Cholangiocarcinoma-associated mortality has been increasing over the past decade. The sodium-glucose cotransporter 2 inhibitor, canagliflozin, has demonstrated anti-tumor effects against several types of cancers; however, studies examining its potential impact on cholangiocarcinoma are lacking. This study investigated the anti-tumor effects of canagliflozin on cholangiocarcinoma and the effects of nicotinamide adenine dinucleotide (NAD)+ salvage pathway activation and sirtuin 1 on tumor growth. We evaluated cell proliferation and gene expression in several cholangiocarcinoma cell lines and analyzed the effects of canagliflozin on cell proliferation, apoptosis, and migration. Canagliflozin treatment decreased the viability of cholangiocarcinoma cells in a concentration-dependent manner but increased the viability at low concentrations in several cell lines. At high concentrations, canagliflozin arrested the cell cycle checkpoint in the G0/G1 phase. In contrast, at low concentrations, it increased the proportion of cells in the S phase. Canagliflozin also reduced the migratory ability of cholangiocarcinoma cells in a concentration-dependent manner. Canagliflozin treatment upregulated nicotinamide phosphoribosyltransferase (NAMPT), NAD+, and sirtuin 1 in cholangiocarcinoma and activated the NAD+ salvage pathway. The growth-inhibitory effect of canagliflozin was enhanced when combined with an NAMPT inhibitor. Canagliflozin inhibits cholangiocarcinoma cell growth and migration and its anti-tumor effect is enhanced when combined with an NAMPT inhibitor. However, further investigation is required because of its potential tumor growth-promoting effect through the activation of the NAD+ salvage pathway.

Combination of dapagliflozin and pioglitazone lacks superiority against monotherapy in streptozotocin-induced nephropathy

Oxidative stress and apoptosis are highly engaged in development of diabetic nephropathy (DN). In monotherapy, dapagliflozin and pioglitazone positively modulate target organ damage even independently of their hypoglycaemic effect. This study evaluated whether a simultaneous PPARγ activation and SGLT cotransporter inhibition offer superior protection against DN-related oxidative and apoptotic processes in a T1DM rat model. Diabetes was induced in Wistar rats using streptozotocin (55 mg/kg, i.p.). The rats received daily chow containing dapagliflozin (10 mg/kg), pioglitazone (12 mg/kg) or their combination. Six weeks after STZ administration, histological and molecular analyses were performed in excised kidneys. STZ-induced DN was demonstrated by the propagation of apoptotic (Bax, p53, Casp3) and oxidative reactions (Gp91phox, MnSOD) and disrupted nitric oxide signalling (eNOS, Hsp90, Cav1). Kidney damage molecule expression (Kim1, Nphs1) revealed a deceleration of kidney damage by pioglitazone and dapagliflozine monotherapies. The monotherapy also reduced apoptosis, oxidative stress, and partially restored NO signalling. The combined therapy ameliorated glomerulosclerosis but in other measured parameters, it reached the effect of the monotherapies except for Hsp90 expression modulation. Both dapagliflozin and pioglitazone exert protective character in kidneys when used in monotherapy. The combined therapy does not exhibit an expected additive effect within modulating oxidative stress, NO signalling or apoptosis.

Melittin alleviates bleomycin-induced pulmonary fibrosis in vivo through regulating TGF-β1/Smad2/3 and AMPK/SIRT1/PGC-1α signaling pathways

Objectives

The present study investigated the protective effect of melittin (MEL) against bleomycin (BLM)- induced pulmonary fibrosis (PF) in mice and the mechanism underlying this effect.

Materials and Methods

A mouse model of PF was established by intratracheal injection of 3.5 mg/kg BLM. Twenty-four hours after the model was established, the mice in the treatment groups were intraperitoneally injected with MEL, and specimens were collected 28 days later. The body weight, survival rate, and pulmonary index (PI) of the mice were determined. Haematoxylin and eosin (HE) staining, Masson's trichrome staining, immunohistochemical staining, kit assays, and Western blot (WB) analysis were performed.

Results

Our study indicated that MEL significantly increased the body weight and survival rate, reduced PI, and improved lung histopathology in mice. In addition, MEL inhibited epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) deposition. Attenuated mitochondrial damage and reduced oxidative stress (OS) were also observed in MEL-treated mice. We further showed that MEL inhibited the TGF-β1/Smad2/3 pathway and activated the AMPK/SIRT1/PGC-1α pathway.

Conclusion

MEL is a promising future therapeutic agent for PF. Its multifaceted and complex mechanism of action inhibits both EMT and ECM production by modulating the TGF-β1/Smad2/3 pathway. It also improves mitochondrial function and reduces OS at least partially through the activation of the AMPK/SIRT1/PGC-1α signaling pathway.

Role of Abscisic Acid in the Whole-Body Regulation of Glucose Uptake and Metabolism

Abscisic acid (ABA) is a hormone with a long evolutionary history, dating back to the earliest living organisms, of which modern (ABA-producing) cyanobacteria are likely descendants, which existed long before the separation of the plant and animal kingdoms, with a conserved role as signals regulating cell responses to environmental challenges. In mammals, along with the anti-inflammatory and neuroprotective function of ABA, nanomolar ABA regulates the metabolic response to glucose availability by stimulating glucose uptake in skeletal muscle and adipose tissue via an insulin-independent mechanism and increasing metabolic energy production and also dissipation in brown and white adipocytes. Chronic ABA intake of micrograms per Kg body weight improves blood glucose, lipids, and morphometric parameters (waist circumference and body mass index) in borderline subjects for prediabetes and metabolic syndrome. This review summarizes the most recent in vitro and in vivo data obtained with nanomolar ABA, the involvement of the receptors LANCL1 and LANCL2 in the hormone's action, and the importance of mammals' endowment with two distinct hormones governing the metabolic response to glucose availability. Finally, unresolved issues and future directions for the clinical use of ABA in diabetes are discussed.

Effects of single or combined exposure to tralopyril and ocean acidification on energy metabolism response and sex development in Pacific oysters (Crassostrea gigas)

The combined effects of the novel antifouling biocide tralopyril (TP) nitrile and ocean acidification (OA) on marine organisms are still not well understood, despite the increasing attention given to the toxic effects of emerging pollutants and OA on marine organisms in recent years. In this study, Crassostrea gigas (C. gigas) was exposed to TP, OA, and a combination of TP and OA for 21 days with a 14-day depuration. This study investigated the inter-tissue variability in energy metabolism responses and the impacts on gonadal development in C. gigas under both single and combined exposures to TP and OA. The results indicate that TP exposure and OA resulted in up-regulation of energy metabolism genes in the C. gigas, with tissues exhibiting enhanced aerobic metabolism. Furthermore, OA influences the sex determination of C. gigas, promoting the development of female individuals. Moreover, following depuration, C. gigas is able to restore normal energy metabolism and sexual development through the accumulation of suitable energy reserves. This study provides a valuable reference for the environmental and ecological risk assessment of TP, addressing the research gap in understanding the combined toxicity of TP and OA on aquatic organisms.

Swertiamarin ameliorates type 2 diabetes by activating ADRB3/UCP1 thermogenic signals in adipose tissue

BACKGROUND AND PURPOSE

Swertiamarin (STM), a secoiridoid glycoside from Swertia chirayita (Roxb.) H. Karst, has been shown to decrease body weight, blood glucose, and blood lipids by inhibiting adipose tissue hypertrophy. However, the underlying mechanisms remain unclear. In particular, adipose thermogenesis is a novel avenue for exploring the pharmacological effects of STM. We aim to investigate the efficacy of STM on type 2 diabetes mellitus (T2DM), with a focus on underlying mechanisms, particularly the activation of ADRB3/UCP1 thermogenic signaling pathways.

METHODS

T2DM model was established by a high-fat diet (HFD) and streptozotocin (STZ) in C57BL/6 J male mice. Mice were given to either 100 or 200 mg kg-1/day of STM, or 200 mg kg-1/day of metformin (Glucophage) via intragastric administration for 7 weeks. In vitro, 3T3-L1 cells were differentiated into adipocytes. Molecular markers related to ADRB3-UCP1 signals, lipolysis, and mitochondrial function were detected.

RESULTS

STM-treated diabetic mice showed a reduction of body weight, fat mass, and blood glucose/lipids and an improvement in insulin sensitivity. Bioinformatics analysis indicated STM promoted lipid metabolism and mitochondrial function, features by closely associated with adipose thermogenesis. STM upregulated the lipolysis-related genes and p-HSL protein in inguinal subcutaneous white adipose tissue (igSWAT) and brown adipose tissue (BAT). STM-treated mice processed a more active energy metabolism. Additionally, the ADRB3-UCP1 signals, mitochondrial-related genes, and oxidative phosphorylation were improved in igSWAT and BAT. In vitro, we found STM interacted with ADRB3, increasing glucose uptake, glycerol release, ADRB3-UCP1 signals, p-HSL expression, mitochondrial content, oxidative phosphorylation complex expression with improved mitochondrial Δψm, as well as reduced lipid accumulation in adipocytes. All these effects were reversed upon ADRB3 inhibition.

CONCLUSION

This study identifies a previously unknown role of STM activating ADRB3/UCP1 signals in adipose tissue, suggesting a potential strategy for treating T2DM.

Mechanisms and therapeutic potential of chinonin in nervous system diseases

The flavonoid compound chinonin is one of the main active components of Rhizoma anemarrhena with multiple activities, including anti-inflammatory and antioxidant properties, protection of mitochondrial function and regulation of immunity. In this paper, we reviewed recent research progress on the protective effect of chinonin on brain injury in neurological diseases. "Chinonin" OR "Mangiferin" AND "Nervous system diseases" OR "Neuroprotection" was used as the terms for search in PumMed. After discarding duplicated and irrelevant articles, a total of 23 articles relevant to chinonin published between 2012 and 2023 were identified in our study.

Aberrant PGC-1α signaling in a lamb model of persistent pulmonary hypertension of the newborn

BACKGROUND

Persistent Pulmonary Hypertension of the Newborn (PPHN) is characterized by elevated pulmonary vascular resistance (PVR), resulting in hypoxemia. Impaired angiogenesis contributes to high PVR. Pulmonary artery endothelial cells (PAECs) in PPHN exhibit decreased mitochondrial respiration and angiogenesis. We hypothesize that Peroxisome Proliferator-Activated Receptor Gamma Co-Activator-1α (PGC-1α) downregulation leads to reduced mitochondrial function and angiogenesis in PPHN.

METHODS

Studies were performed in PAECs isolated from fetal lambs with PPHN induced by ductus arteriosus constriction, with gestation-matched controls and in normal human umbilical vein endothelial cells (HUVECs). PGC-1α was knocked downed in control lamb PAECs and HUVECs and overexpressed in PPHN PAECs to investigate the effects on mitochondrial function and angiogenesis.

RESULTS

PPHN PAECs had decreased PGC-1α expression compared to controls. PGC-1α knockdown in HUVECs led to reduced Nuclear Respiratory Factor-1 (NRF-1), Transcription Factor-A of Mitochondria (TFAM), and mitochondrial electron transport chain (ETC) complexes expression. PGC-1α knockdown in control PAECs led to decreased in vitro capillary tube formation, cell migration, and proliferation. PGC-1α upregulation in PPHN PAECs led to increased ETC complexes expression and improved tube formation, cell migration, and proliferation.

CONCLUSION

PGC-1α downregulation contributes to reduced mitochondrial oxidative phosphorylation through control of the ETC complexes, thereby affecting angiogenesis in PPHN.

IMPACT

Reveals a novel mechanism for angiogenesis dysfunction in persistent pulmonary hypertension of the newborn (PPHN). Identifies a key mitochondrial transcription factor, Peroxisome Proliferator-Activated Receptor Gamma Co-Activator-1α (PGC-1α), as contributing to the altered adaptation and impaired angiogenesis function that characterizes PPHN through its regulation of mitochondrial function and oxidative phosphorylation. May provide translational significance as this mechanism offers a new therapeutic target in PPHN, and efforts to restore PGC-1α expression may improve postnatal transition in PPHN.

Research progress on the association of insulin resistance with type 2 diabetes mellitus and Alzheimer's disease

Type 2 diabetes mellitus (T2DM) is a metabolic disorder that is characterized by insulin resistance and hyperglycemia. It is also known to be a risk factor for Alzheimer's disease (AD). Insulin plays a crucial role in regulating the body's metabolism and is responsible for activating the Phosphoinotide-3-Kinase (PI3K)/Protein Kinase B (Akt) signaling pathway. This pathway is activated when insulin binds to the insulin receptor on nerve cells, and it helps regulate the metabolism of glucose and lipids. Dysfunction in the insulin signaling pathway can lead to a decrease in brain insulin levels and insulin sensitivity, thereby inducing disruptions in insulin signal transduction and leading to disorders in brain energy metabolism. Moreover, these dysfunctions also contribute to the accumulation of β-amyloid (Aβ) deposition and the hyperphosphorylation of Tau protein, both of which are characteristic features of AD. Therefore, this article focuses on insulin resistance to reveal the complex mechanism between brain insulin resistance and AD occurrence in T2DM. On this basis, this article further summarizes the biological effects and mechanisms of antidiabetic drugs on the two diseases, aiming to provide new ideas for the discovery of drugs for the treatment of T2DM combined with AD.

Extrarenal Benefits of SGLT2 Inhibitors in the Treatment of Cardiomyopathies

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have emerged as pivotal medications for heart failure, demonstrating remarkable cardiovascular benefits extending beyond their glucose-lowering effects. The unexpected cardiovascular advantages have intrigued and prompted the scientific community to delve into the mechanistic underpinnings of these novel actions. Preclinical studies have generated many mechanistic theories, ranging from their renal and extrarenal effects to potential direct actions on cardiac muscle cells, to elucidate the mechanisms linking these drugs to clinical cardiovascular outcomes. Despite the strengths and limitations of each theory, many await validation in human studies. Furthermore, whether SGLT2 inhibitors confer therapeutic benefits in specific subsets of cardiomyopathies akin to their efficacy in other heart failure populations remains unclear. By examining the shared pathological features between heart failure resulting from vascular diseases and other causes of cardiomyopathy, certain specific molecular actions of SGLT2 inhibitors (particularly those targeting cardiomyocytes) would support the concept that these medications will yield therapeutic benefits across a broad range of cardiomyopathies. This article aims to discuss the important mechanisms of SGLT2 inhibitors and their implications in hypertrophic and dilated cardiomyopathies. Furthermore, we offer insights into future research directions for SGLT2 inhibitor studies, which hold the potential to further elucidate the proposed biological mechanisms in greater detail.

AdipoRon Alleviates Liver Injury by Protecting Hepatocytes from Mitochondrial Damage Caused by Ionizing Radiation

Radiation liver injury is a common complication of hepatocellular carcinoma radiotherapy. It is mainly caused by irreversible damage to the DNA of hepatocellular cells directly by radiation, which seriously interferes with metabolism and causes cell death. AdipoRon can maintain lipid metabolism and stabilize blood sugar by activating adiponectin receptor 1 (AdipoR1). However, the role of AdipoRon/AdipoR1 in the regulation of ionizing radiation (IR)-induced mitochondrial damage remains unclear. In this study, we aimed to elucidate the roles of AdipoRon/AdipoR1 in IR-induced mitochondrial damage in normal hepatocyte cells. We found that AdipoRon treatment rescued IR-induced liver damage in mice and mitochondrial damage in normal hepatocytes in vivo and in vitro. AdipoR1 deficiency exacerbated IR-induced oxidative stress, mitochondrial dynamics, and biogenesis disorder. Mechanistically, the absence of AdipoR1 inhibits the activity of adenosine monophosphate-activated protein kinase α (AMPKα), subsequently leading to disrupted mitochondrial dynamics by decreasing mitofusin (MFN) and increasing dynamin-related protein 1 (DRP1) protein expression. It also controls mitochondrial biogenesis by suppressing the peroxisome proliferator-activated receptor-gamma coactivator-1 alpha (PGC1α) and transcription factor A (TFAM) signaling pathway, ultimately resulting in impaired mitochondrial function. To sum up, AdipoRon/AdipoR1 maintain mitochondrial function by regulating mitochondrial dynamics and biogenesis through the AdipoR1-AMPKα signaling pathway. This study reveals the significant role of AdipoR1 in regulating IR-induced mitochondrial damage in hepatocytes and offers a novel approach to protecting against damage caused by IR.

Targeting the Sirtuin-1/PPAR-Gamma Axis, RAGE/HMGB1/NF-κB Signaling, and the Mitochondrial Functions by Canagliflozin Augments the Protective Effects of Levodopa/Carbidopa in Rotenone-Induced Parkinson's Disease

Background and Objectives: Parkinson's disease (PD) is a pathological state characterized by a combined set of abnormal movements including slow motion, resting tremors, profound stiffness of skeletal muscles, or obvious abnormalities in posture and gait, together with significant behavioral changes. Until now, no single therapeutic modality was able to provide a complete cure for PD. This work was a trial to assess the immunomodulatory effects of canagliflozin with or without levodopa/carbidopa on rotenone-induced parkinsonism in Balb/c mice. Materials and Methods: In a mouse model of PD, the effect of canagliflozin with or without levodopa/carbidopa was assessed at the behavioral, biochemical, and histopathological levels. Results: The combination of levodopa/carbidopa and canagliflozin significantly mitigated the changes induced by rotenone administration regarding the behavioral tests, striatal dopamine, antioxidant status, Nrf2 content, SIRT-1/PPAR-gamma axis, RAGE/HMGB1/NF-κB signaling, and mitochondrial dysfunction; abrogated the neuroinflammatory responses, and alleviated the histomorphologic changes induced by rotenone administration relative to the groups that received either levodopa/carbidopa or canagliflozin alone. Conclusions: Canagliflozin may represent a new adjuvant therapeutic agent that may add value to the combatting effects of levodopa/carbidopa against the pathological effects of PD.

Multifaceted Impact of SGLT2 Inhibitors in Heart Failure Patients: Exploring Diverse Mechanisms of Action

Heart failure (HF) is a growing concern due to the aging population and increasing prevalence of comorbidities. Despite advances in treatment, HF remains a significant burden, necessitating novel therapeutic approaches. Sodium-glucose cotransporter 2 inhibitors (SGLT2is) have emerged as a promising treatment option, demonstrating benefits across the entire spectrum of HF, regardless of left ventricular ejection fraction (LVEF). This review explores the multifaceted mechanisms through which SGLT2is exert cardioprotective effects, including modulation of energy metabolism, reduction of oxidative stress, attenuation of inflammation, and promotion of autophagy. SGLT2is shift myocardial energy substrate utilization from carbohydrates to more efficient fatty acids and ketone bodies, enhancing mitochondrial function and reducing insulin resistance. These inhibitors also mitigate oxidative stress by improving mitochondrial biogenesis, reducing reactive oxygen species (ROS) production, and regulating calcium-signaling pathways. Inflammation, a key driver of HF progression, is alleviated through the suppression of proinflammatory cytokines and modulation of immune cell activity. Additionally, SGLT2is promote autophagy, facilitating the clearance of damaged cellular components and preserving myocardial structure and function. Beyond their glucose-lowering effects, SGLT2is provide significant benefits in patients with chronic kidney disease (CKD) and HF, reducing the progression of CKD and improving overall survival. The pleiotropic actions of SGLT2is highlight their potential as a cornerstone in HF management. Further research is needed to fully elucidate their mechanisms and optimize their use in clinical practice.

Mitochondrial Function and Dysfunction in White Adipocytes and Therapeutic Implications

For a long time, white adipocytes were thought to function as lipid storages due to the sizeable unilocular lipid droplet that occupies most of their space. However, recent discoveries have highlighted the critical role of white adipocytes in maintaining energy homeostasis and contributing to obesity and related metabolic diseases. These physiological and pathological functions depend heavily on the mitochondria that reside in white adipocytes. This article aims to provide an up-to-date overview of the recent research on the function and dysfunction of white adipocyte mitochondria. After briefly summarizing the fundamental aspects of mitochondrial biology, the article describes the protective role of functional mitochondria in white adipocyte and white adipose tissue health and various roles of dysfunctional mitochondria in unhealthy white adipocytes and obesity. Finally, the article emphasizes the importance of enhancing mitochondrial quantity and quality as a therapeutic avenue to correct mitochondrial dysfunction, promote white adipocyte browning, and ultimately improve obesity and its associated metabolic diseases. © 2024 American Physiological Society. Compr Physiol 14:5581-5640, 2024.

Role of mitochondria in reno-cardiac diseases: A study of bioenergetics, biogenesis, and GSH signaling in disease transition

Acute kidney injury (AKI) and chronic kidney disease (CKD) are global health burdens with rising prevalence. Their bidirectional relationship with cardiovascular dysfunction, manifesting as cardio-renal syndromes (CRS) types 3 and 4, underscores the interconnectedness and interdependence of these vital organ systems. Both the kidney and the heart are critically reliant on mitochondrial function. This organelle is currently recognized as a hub in signaling pathways, with emphasis on the redox regulation mediated by glutathione (GSH). Mitochondrial dysfunction, including impaired bioenergetics, redox, and biogenesis pathways, are central to the progression of AKI to CKD and the development of CRS type 3 and 4. This review delves into the metabolic reprogramming and mitochondrial redox signaling and biogenesis alterations in AKI, CKD, and CRS. We examine the pathophysiological mechanisms involving GSH redox signaling and the AMP-activated protein kinase (AMPK)-sirtuin (SIRT)1/3-peroxisome proliferator-activated receptor-gamma coactivator (PGC-1α) axis in these conditions. Additionally, we explore the therapeutic potential of GSH synthesis inducers in mitigating these mitochondrial dysfunctions, as well as their effects on inflammation and the progression of CKD and CRS types 3 and 4.

Protective Mechanisms of SGLTi in Ischemic Heart Disease

Ischemic heart disease (IHD) is a common clinical cardiovascular disease with high morbidity and mortality. Sodium glucose cotransporter protein inhibitor (SGLTi) is a novel hypoglycemic drug. To date, both clinical trials and animal experiments have shown that SGLTi play a protective role in IHD, including myocardial infarction (MI) and ischemia/reperfusion (I/R). The protective effects may be involved in mechanisms of energy metabolic conversion, anti-inflammation, anti-fibrosis, ionic homeostasis improvement, immune cell development, angiogenesis and functional regulation, gut microbiota regulation, and epicardial lipids. Thus, this review summarizes the above mechanisms and aims to provide theoretical evidence for therapeutic strategies for IHD.

Protein posttranslational modifications in metabolic diseases: basic concepts and targeted therapies

Metabolism-related diseases, including diabetes mellitus, obesity, hyperlipidemia, and nonalcoholic fatty liver disease, are becoming increasingly prevalent, thereby posing significant threats to human health and longevity. Proteins, as the primary mediators of biological activities, undergo various posttranslational modifications (PTMs), including phosphorylation, ubiquitination, acetylation, methylation, and SUMOylation, among others, which substantially diversify their functions. These modifications are crucial in the physiological and pathological processes associated with metabolic disorders. Despite advancements in the field, there remains a deficiency in contemporary summaries addressing how these modifications influence processes of metabolic disease. This review aims to systematically elucidate the mechanisms through which PTM of proteins impact the progression of metabolic diseases, including diabetes, obesity, hyperlipidemia, and nonalcoholic fatty liver disease. Additionally, the limitations of the current body of research are critically assessed. Leveraging PTMs of proteins provides novel insights and therapeutic targets for the prevention and treatment of metabolic disorders. Numerous drugs designed to target these modifications are currently in preclinical or clinical trials. This review also provides a comprehensive summary. By elucidating the intricate interplay between PTMs and metabolic pathways, this study advances understanding of the molecular mechanisms underlying metabolic dysfunction, thereby facilitating the development of more precise and effective disease management strategies.

Iron supplementation and iron accumulation promote adipocyte thermogenesis through PGC1α-ATGL-mediated lipolysis

Iron homeostasis is essential for maintaining metabolic health and iron disorder has been linked to chronic metabolic diseases. Increasing thermogenic capacity in adipose tissue has been considered as a potential approach to regulate energy homeostasis. Both mitochondrial biogenesis and mitochondrial function are iron-dependent and essential for adipocyte thermogenic capacity, but the underlying relationships between iron accumulation and adipose thermogenesis is unclear. Firstly, we confirmed that iron homeostasis and the iron regulatory markers (e.g., Tfr1 and Hfe) are involved in cold-induced thermogenesis in subcutaneous adipose tissues using RNA-seq and bioinformatic analysis. Secondly, an Hfe (Hfe-/-)-deficient mouse model, in which tissues become overloaded with iron, was employed. We found iron accumulation caused by Hfe deficiency enhanced mitochondrial respiratory chain expression in subcutaneous white adipose in vivo and resulted in enhanced tissue thermogenesis with upregulation of PGC-1α and adipose triglyceride lipase, mitochondrial biogenesis and lipolysis. To investigate the thermogenic capacity in vitro, stromal vascular fraction from adipose tissues was isolated, followed with adipogenic differentiation. Primary adipocyte from Hfe-/- mice exhibited higher cellular oxygen consumption, associated with enhanced expression of mitochondrial oxidative respiratory chain protein, while primary adipocytes or stromal vascular fractions from WT mice supplemented with iron citrate) exhibited similar effect in thermogenic capacity. Taken together, these findings indicate iron supplementation and iron accumulation (Hfe deficiency) can regulate adipocyte thermogenic capacity, suggesting a potential role for iron homeostasis in adipose tissues.

From fasting to fat reshaping: exploring the molecular pathways of intermittent fasting-induced adipose tissue remodeling

Obesity, characterised by excessive fat accumulation, is a complex chronic condition that results from dysfunctional adipose tissue expansion due to prolonged calorie surplus. This leads to rapid adipocyte enlargement that exceeds the support capacity of the surrounding neurovascular network, resulting in increased hypoxia, inflammation, and insulin resistance. Intermittent fasting (IF), a dietary regimen that cycles between periods of fasting and eating, has emerged as an effective strategy to combat obesity and improve metabolic homeostasis by promoting healthy adipose tissue remodeling. However, the precise molecular and cellular mechanisms behind the metabolic improvements and remodeling of white adipose tissue (WAT) driven by IF remain elusive. This review aims to summarise and discuss the relationship between IF and adipose tissue remodeling and explore the potential mechanisms through which IF induces alterations in WAT. This includes several key structural changes, including angiogenesis and sympathetic innervation of WAT. We will also discuss the involvement of key signalling pathways, such as PI3K, SIRT, mTOR, and AMPK, which potentially play a crucial role in IF-mediated metabolic adaptations.

The potential anti-arrhythmic effect of SGLT2 inhibitors

Sodium-glucose cotransporter type 2 inhibitors (SGLT2i) were initially recommended as oral anti-diabetic drugs to treat type 2 diabetes (T2D), by inhibiting SGLT2 in proximal tubule and reduce renal reabsorption of sodium and glucose. While many clinical trials demonstrated the tremendous potential of SGLT2i for cardiovascular diseases. 2022 AHA/ACC/HFSA guideline first emphasized that SGLT2i were the only drug class that can cover the entire management of heart failure (HF) from prevention to treatment. Subsequently, the antiarrhythmic properties of SGLT2i have also attracted attention. Although there are currently no prospective studies specifically on the anti-arrhythmic effects of SGLT2i. We provide clues from clinical and fundamental researches to identify its antiarrhythmic effects, reviewing the evidences and mechanism for the SGLT2i antiarrhythmic effects and establishing a novel paradigm involving intracellular sodium, metabolism and autophagy to investigate the potential mechanisms of SGLT2i in mitigating arrhythmias.

Canagliflozin Mitigates Diabetic Cardiomyopathy through Enhanced PINK1-Parkin Mitophagy

Diabetic cardiomyopathy (DCM) is a major determinant of mortality in diabetic populations, and the potential strategies are insufficient. Canagliflozin has emerged as a potential cardioprotective agent in diabetes, yet its underlying molecular mechanisms remain unclear. We employed a high-glucose challenge (60 mM for 48 h) in vitro to rat cardiomyocytes (H9C2), with or without canagliflozin treatment (20 µM). In vivo, male C57BL/6J mice were subjected to streptozotocin and a high-fat diet to induce diabetes, followed by canagliflozin administration (10, 30 mg·kg-1·d-1) for 12 weeks. Proteomics and echocardiography were used to assess the heart. Histopathological alterations were assessed by the use of Oil Red O and Masson's trichrome staining. Additionally, mitochondrial morphology and mitophagy were analyzed through biochemical and imaging techniques. A proteomic analysis highlighted alterations in mitochondrial and autophagy-related proteins after the treatment with canagliflozin. Diabetic conditions impaired mitochondrial respiration and ATP production, alongside decreasing the related expression of the PINK1-Parkin pathway. High-glucose conditions also reduced PGC-1α-TFAM signaling, which is responsible for mitochondrial biogenesis. Canagliflozin significantly alleviated cardiac dysfunction and improved mitochondrial function both in vitro and in vivo. Specifically, canagliflozin suppressed mitochondrial oxidative stress, enhancing ATP levels and sustaining mitochondrial respiratory capacity. It activated PINK1-Parkin-dependent mitophagy and improved mitochondrial function via increased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK). Notably, PINK1 knockdown negated the beneficial effects of canagliflozin on mitochondrial integrity, underscoring the critical role of PINK1 in mediating these protective effects. Canagliflozin fosters PINK1-Parkin mitophagy and mitochondrial function, highlighting its potential as an effective treatment for DCM.

Sodium-glucose cotransporter-2 inhibitors protect tissues via cellular and mitochondrial pathways: Experimental and clinical evidence

Mitochondrial dysfunction is a key driver of cardiovascular disease (CVD) in metabolic syndrome and diabetes. This dysfunction promotes the production of reactive oxygen species (ROS), which cause oxidative stress and inflammation. Angiotensin II, the main mediator of the renin-angiotensin-aldosterone system, also contributes to CVD by promoting ROS production. Reduced activity of sirtuins (SIRTs), a family of proteins that regulate cellular metabolism, also worsens oxidative stress. Reduction of energy production by mitochondria is a common feature of all metabolic disorders. High SIRT levels and 5' adenosine monophosphate-activated protein kinase signaling stimulate hypoxia-inducible factor 1 beta, which promotes ketosis. Ketosis, in turn, increases autophagy and mitophagy, processes that clear cells of debris and protect against damage. Sodium-glucose cotransporter-2 inhibitors (SGLT2i), a class of drugs used to treat type 2 diabetes, have a beneficial effect on these mechanisms. Randomized clinical trials have shown that SGLT2i improves cardiac function and reduces the rate of cardiovascular and renal events. SGLT2i also increase mitochondrial efficiency, reduce oxidative stress and inflammation, and strengthen tissues. These findings suggest that SGLT2i hold great potential for the treatment of CVD. Furthermore, they are proposed as anti-aging drugs; however, rigorous research is needed to validate these preliminary findings.

SGLT2 inhibitor promotes mitochondrial dysfunction and ER-phagy in colorectal cancer cells

BACKGROUND

Sodium-glucose transporter 2 (SGLT2) inhibitors (iSGLT2) are approved medications for type 2 diabetes. Recent studies indicate that iSGLT2 inhibit the growth of some cancer cells. However, the mechanism(s) remains to be fully elucidated.

METHODS

The SGLT2 levels were determined in normal colon CCD 841 CoN and, HCT 116, HT-29, SW480 and LoVo colorectal cancer (CRC) cell lines by quantitative real-time PCR and western blot. The effect of iSGLT2 canagliflozin on cell proliferation was examined using CCK-8, as its role on CRC cells metabolism and tumorigenesis has been evaluated by XF HS Seahorse Bioanalyzer and flow cytometric analyses. Transient gene silencing experiments and analysis of protein-protein interaction network were conducted to evaluate the SGLT2 molecular targets in CRC cells.

RESULTS

Data showed that the treatment with iSGLT2 (50 µM) for 72 h induced cell cycle arrest (p < 0.001), impaired glucose and energetic metabolism (p < 0.001), promoted apoptotic cell death and ER stress flowing into autophagy (p < 0.001) in HCT 116 and HT-29 cells. These cellular events were accompanied by sirtuin 3 (SIRT3) upregulation (p < 0.01), as also supported by SIRT3 transient silencing experiments resulting in the attenuation of the effects of iSGLT2 on the cellular metabolic/energetic alterations and the induction of programmed cell death. The identification and validation of dipeptidyl peptidase 4 (DPP4) as potential common target of SGLT2 and SIRT3 were also assessed.

CONCLUSIONS

These results deepened knowledge on the iSGLT2 contribution in limiting CRC tumorigenesis unveiling the SGLT2/SIRT3 axis in the cytotoxic mechanisms.

Estrogen-Related Receptor α: A Key Transcription Factor in the Regulation of Energy Metabolism at an Organismic Level and a Target of the ABA/LANCL Hormone Receptor System

The orphan nuclear receptor ERRα is the most extensively researched member of the estrogen-related receptor family and holds a pivotal role in various functions associated with energy metabolism, especially in tissues characterized by high energy requirements, such as the heart, skeletal muscle, adipose tissue, kidney, and brain. Abscisic acid (ABA), traditionally acknowledged as a plant stress hormone, is detected and actively functions in organisms beyond the land plant kingdom, encompassing cyanobacteria, fungi, algae, protozoan parasites, lower Metazoa, and mammals. Its ancient, cross-kingdom role enables ABA and its signaling pathway to regulate cell responses to environmental stimuli in various organisms, such as marine sponges, higher plants, and humans. Recent advancements in understanding the physiological function of ABA and its mammalian receptors in governing energy metabolism and mitochondrial function in myocytes, adipocytes, and neuronal cells suggest potential therapeutic applications for ABA in pre-diabetes, diabetes, and cardio-/neuroprotection. The ABA/LANCL1-2 hormone/receptor system emerges as a novel regulator of ERRα expression levels and transcriptional activity, mediated through the AMPK/SIRT1/PGC-1α axis. There exists a reciprocal feed-forward transcriptional relationship between the LANCL proteins and transcriptional coactivators ERRα/PGC-1α, which may be leveraged using natural or synthetic LANCL agonists to enhance mitochondrial function across various clinical contexts.

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.

Metabolic vulnerability of cancer stem cells and their niche

Cancer stem cells (CSC) are the leading cause of the failure of anti-tumor treatments. These aggressive cancer cells are preserved and sustained by adjacent cells forming a specialized microenvironment, termed niche, among which tumor-associated macrophages (TAMs) are critical players. The cycle of tricarboxylic acids, fatty acid oxidation path, and electron transport chain have been proven to play central roles in the development and maintenance of CSCs and TAMs. By improving their oxidative metabolism, cancer cells are able to extract more energy from nutrients, which allows them to survive in nutritionally defective environments. Because mitochondria are crucial bioenergetic hubs and sites of these metabolic pathways, major hopes are posed for drugs targeting mitochondria. A wide range of medications targeting mitochondria, electron transport chain complexes, or oxidative enzymes are currently investigated in phase 1 and phase 2 clinical trials against hard-to-treat tumors. This review article aims to highlight recent literature on the metabolic adaptations of CSCs and their supporting macrophages. A focus is provided on the resistance and dormancy behaviors that give CSCs a selection advantage and quiescence capacity in particularly hostile microenvironments and the role of TAMs in supporting these attitudes. The article also describes medicaments that have demonstrated a robust ability to disrupt core oxidative metabolism in preclinical cancer studies and are currently being tested in clinical trials.

Anti-Obesity Effect of Jeju Roasted Citrus Peel Extract in High-Fat Diet-Induced Obese Mice and 3T3-L1 Adipocytes Via Lipid Metabolism Regulation

Lipid accumulation in adipocytes occurs through multifactorial effects such as overnutrition due to unbalanced eating habits, reduced physical activity, and genetic factors. In addition, obesity can be intensified by the dis-regulation of various metabolic systems such as differentiation, lipogenesis, lipolysis, and energy metabolism of adipocytes. In this study, the Jeju roasted peel extract from Citrus unshiu S.Markov. (JRC), which is discarded as opposed to the pulp of C. unshiu S.Markov., is commonly consumed to ameliorate obesity. To investigate the anti-obesity effect of JRC, these studies were conducted on differentiated 3T3-L1 cells and in high-fat diet-induced mice, and related methods were used to confirm whether it decreased lipid accumulation in adipocytes. The mechanism of inhibiting obesity by JRC was confirmed through mRNA expression studies. JRC suppressed lipid accumulation in adipocytes and adipose tissue, and significantly improved enzymes such as alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase and serum lipid profiles. In addition, it effectively modulated the expression of genes related to lipid and energy metabolism in adipose tissue. As a result, these findings suggest that JRC could be a therapeutic regulator of body fat accumulation by significantly alleviating the dis-regulation of intracellular lipid metabolism in adipocytes and by enhancement of energy metabolism (Approval No. CNU IACUC-YB-2023-98).

The potential of therapeutic strategies targeting mitochondrial biogenesis for the treatment of insulin resistance and type 2 diabetes mellitus

Type 2 diabetes mellitus (T2DM) is a persistent metabolic disorder marked by deficiencies in insulin secretion and/or function, affecting various tissues and organs and leading to numerous complications. Mitochondrial biogenesis, the process by which cells generate new mitochondria utilizing existing ones plays a crucial role in energy homeostasis, glucose metabolism, and lipid handling. Recent evidence suggests that promoting mitochondrial biogenesis can alleviate insulin resistance in the liver, adipose tissue, and skeletal muscle while improving pancreatic β-cell function. Moreover, enhanced mitochondrial biogenesis has been shown to ameliorate T2DM symptoms and may contribute to therapeutic effects for the treatment of diabetic nephropathy, cardiomyopathy, retinopathy, and neuropathy. This review summarizes the intricate connection between mitochondrial biogenesis and T2DM, highlighting the potential of novel therapeutic strategies targeting mitochondrial biogenesis for T2DM treatment and its associated complications. It also discusses several natural products that exhibit beneficial effects on T2DM by promoting mitochondrial biogenesis.

AMPK-mediated autophagy is involved in the protective effect of canagliflozin in the vitamin D3 plus nicotine calcification model in rats

Vascular calcification (VC) is a major risk factor for cardiovascular events. A mutual interplay between inflammation, oxidative stress, apoptosis, and autophagy is implicated in its development. Herein, we aimed to evaluate the potential protective effects of canagliflozin in a vitamin D3 plus nicotine (VDN) model of VC, and to explore potential mechanisms. VC was induced by VDN in adult male Wistar rats on day one. Then, rats were randomly assigned into three groups to receive canagliflozin (10 mg or 20 mg/kg/day) or its vehicle for 4 weeks. Age-matched normal rats served as a control group. After euthanization, aorta and kidneys were harvested for biochemical and histopathological evaluation of calcification. Aortic markers of oxidative stress, alkaline phosphatase (ALP) activity, runt-related transcription factor (Runx2) and bone morphogenic protein-2 (BMP-2) levels were determined. Additionally, the protein expression of autophagic markers, LC3 and p62, and adenosine monophosphate activated protein kinase (AMPK) were also assessed in aortic homogenates. Canagliflozin dose-dependently improved renal function, enhanced the antioxidant capacity of aortic tissues and reduced calcium deposition in rat aortas and kidneys. Both doses of canagliflozin attenuated ALP and osteogenic markers while augmented the expression of autophagic markers and AMPK. Histopathological examination of aortas and kidneys by H&E and Von Kossa stain further support the beneficial effect of canagliflozin. Canagliflozin could alleviate VDN-induced vascular calcification, in a dose dependent manner, via its antioxidant effect and modulation of autophagy. Further studies are needed to verify whether this effect is a member or a class effect.

The favorable impacts of cardamom on related complications of diabetes: A comprehensive literature systematic review

BACKGROUND AND AIM

Complementary and alternative medicine plays an increasing role in preventing, and regulatory, complications associated with diabetes. There are plenty of polyphenolic compounds found in Elettaria cardamomum (Cardamom) such as luteolin, limonene, pelargonidin, caffeic acid, kaempferol, gallic acid, and quercetin which can be used in many metabolic diseases.

METHOD

The objective of this systematic review was to appraise evidence from clinical and in vivo studies on the effects of cardamom on inflammation, blood glucose, oxidative stress and dyslipidemia of diabetes mellitus. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statements, the present study was carried out. Studies were conducted by searching databases such as EMBASE, Scopus, PubMed, Google Scholar, web of sciences, and Cochrane Library from the commencement until April 2022.

RESULTS

All available human and animal studies examining the effects of cardamom on diabetes were published in the form of English articles. Finally, only 14 of the 241 articles met the criteria for analysis. Of the 14 articles, 8 were in vivo studies, and 6 were clinical trial studies. Most studies have indicated the beneficial effects of cardamom on insulin resistance, oxidative stress and inflammation. Cardamom also improved dyslipidemia, but had no substantial effect on weight loss.

CONCLUSION

According to most studies, cardamom supplementation enhanced antioxidant enzyme production and activity in diabetes mellitus and decreased oxidative stress and inflammatory factors. Despite this, the exact mechanism of the disease needs to be identified through more clinical trials.

Mitochondrial damage-associated molecular patterns: A new insight into metabolic inflammation in type 2 diabetes mellitus

The pathogenesis of diabetes is accompanied by increased levels of inflammatory factors, also known as "metabolic inflammation", which runs through the whole process of the occurrence and development of the disease. Mitochondria, as the key site of glucose and lipid metabolism, is often accompanied by mitochondrial function damage in type 2 diabetes mellitus (T2DM). Damaged mitochondria release pro-inflammatory factors through damage-related molecular patterns that activate inflammation pathways and reactions to oxidative stress, further aggravate metabolic disorders, and form a vicious circle. Currently, the pathogenesis of diabetes is still unclear, and clinical treatment focuses primarily on symptomatic intervention of the internal environment of disorders of glucose and lipid metabolism with limited clinical efficacy. The proinflammatory effect of mitochondrial damage-associated molecular pattern (mtDAMP) in T2DM provides a new research direction for exploring the pathogenesis and intervention targets of T2DM. Therefore, this review covers the most recent findings on the molecular mechanism and related signalling cascades of inflammation caused by mtDAMP in T2DM and discusses its pathogenic role of it in the pathological process of T2DM to search potential intervention targets.

Cellular and Mitochondrial Pathways Contribute to SGLT2 Inhibitors-mediated Tissue Protection: Experimental and Clinical Data

In metabolic syndrome and diabetes, compromised mitochondrial function emerges as a critical driver of cardiovascular disease, fueling its development and persistence, culminating in cardiac remodeling and adverse events. In this context, angiotensin II - the main interlocutor of the renin-angiotensin-aldosterone system - promotes local and systemic oxidative inflammatory processes. To highlight, the low activity/expression of proteins called sirtuins negatively participates in these processes, allowing more significant oxidative imbalance, which impacts cellular and tissue responses, causing tissue damage, inflammation, and cardiac and vascular remodeling. The reduction in energy production of mitochondria has been widely described as a significant element in all types of metabolic disorders. Additionally, high sirtuin levels and AMPK signaling stimulate hypoxia- inducible factor 1 beta and promote ketonemia. Consequently, enhanced autophagy and mitophagy advance through cardiac cells, sweeping away debris and silencing the orchestra of oxidative stress and inflammation, ultimately protecting vulnerable tissue from damage. To highlight and of particular interest, SGLT2 inhibitors (SGLT2i) profoundly influence all these mechanisms. Randomized clinical trials have evidenced a compelling picture of SGLT2i emerging as game-changers, wielding their power to demonstrably improve cardiac function and slash the rates of cardiovascular and renal events. Furthermore, driven by recent evidence, SGLT2i emerge as cellular supermolecules, exerting their beneficial actions to increase mitochondrial efficiency, alleviate oxidative stress, and curb severe inflammation. Its actions strengthen tissues and create a resilient defense against disease. In conclusion, like a treasure chest brimming with untold riches, the influence of SGLT2i on mitochondrial function holds untold potential for cardiovascular health. Unlocking these secrets, like a map guiding adventurers to hidden riches, promises to pave the way for even more potent therapeutic strategies.

Effects of dapagliflozin monotherapy and combined aerobic exercise on skeletal muscle mitochondrial quality control and insulin resistance in type 2 diabetes mellitus rats

Type 2 diabetes mellitus (T2DM) is a prevalent, chronic metabolic disease. Sodium-glucose cotransporter-2 (SGLT2) inhibitors and aerobic exercise (AE) have shown promise in mitigating insulin resistance (IR) and T2DM. This study investigated the effects of dapagliflozin (Dapa) monotherapy and combined AE on mitochondrial quality control (MQC) in skeletal muscle and IR in T2DM rats. T2DM rats, induced by a high-fat diet/streptozotocin model, were randomly assigned to the following groups: T2DM+vehicle group (DMV), T2DM rats treated with Dapa (DMDa, 10 mg/kg/d), T2DM rats subjected to combined Dapa treatment and AE (DMDa+AE), and the standard control group (CON). Blood and skeletal muscle samples were collected after 6 weeks of intragastric administration and treadmill exercise. The results showed that DMDa monotherapy could reduce the accumulation of white adipose tissue and skeletal muscle lipid droplets and improve HOMA-IR. While the combined AE led to further reductions in subcutaneous white adipose tissue and fasting glucose levels, it did not confer additional benefits in terms of HOMA-IR. Furthermore, Dapa monotherapy enhanced skeletal muscle mitochondrial biogenesis (PGC-1α, NRF1, TFAM, and COX IV), mitochondrial dynamics (OPA1, DRP1, and MFN2), and mitophagy (PGAM5 and PINK1) related protein levels. Nevertheless, the combination of Dapa with AE treatment did not yield an additive effect. In conclusion, this study highlights the potential of SGLT2 inhibitors, specifically Dapa, in ameliorating IR and maintaining MQC in skeletal muscle in rats with T2DM. However, combined AE did not produce an additive effect, indicating the need for further research.

Autophagy-related 7 proteindependent autophagy mediates resveratrol-caused upregulation of mitochondrial biogenesis and steroidogenesis in aged Leydig cell

BACKGROUND

Mitochondrial dysfunction may contribute to decreased testosterone synthesis in aged Leydig cells. Resveratrol (RSV) as an antioxidant has been shown to exhibit multiple positive effects on mitochondrion, where steroidogenesis takes place. Whether RSV can improve steroidogenesis in aged testis is still unknown. This study investigates the effect of RSV on testosterone production during aging and corresponding changes in mitochondrial biogenesis and autophagy activity, which are closely associated with steroidogenesis. Whether ATG7, an important autophagy-related protein, functions in RSV-treated aged Leydig cells will also be explored.

METHODS AND RESULTS

Two-month-old male C57BL/6 mice were fed for 16 months by customized regular diet with or without RSV as diet supplement. Leydig cell line TM3 cells were treated with D-galactose to induce senescence, followed with or without RSV treatment. Results found that RSV supplement increased testosterone production in both aged mice and D-galactose-induced senescent Leydig cells. Western blot results revealed that RSV treatment elevated levels of steroidogenic rate-limiting enzymes StAR and 3β-HSD, as well as autophagy-related proteins LC3II, Beclin1, ATG5 and ATG7 and mitochondrial function-related proteins mtTFA and COXIV. However, after Atg7 was knocked down in senescent Leydig cells, even though RSV was added, levels of these proteins declined significantly, accompanied by decreased levels of mitochondrial transcript factors PGC-1α, mtTFA and NRF-1 and more fragmented mitochondria, demonstrating that Atg7 knockdown wrecked the protective effects of RSV on steroidogenesis in senescent Leydig cells.

CONCLUSION

ATG7-dependent autophagy plays a key role in RSV-brought testosterone production increase through regulating mitochondrial biogenesis in senescent Leydig cells.

Empagliflozin ameliorates diabetic cardiomyopathy probably via activating AMPK/PGC-1α and inhibiting the RhoA/ROCK pathway

BACKGROUND

Diabetic cardiomyopathy (DCM) increases the risk of hospitalization for heart failure (HF) and mortality in patients with diabetes mellitus. However, no specific therapy to delay the progression of DCM has been identified. Mitochondrial dysfunction, oxidative stress, inflammation, and calcium handling imbalance play a crucial role in the pathological processes of DCM, ultimately leading to cardiomyocyte apoptosis and cardiac dysfunctions. Empagliflozin, a novel glucose-lowering agent, has been confirmed to reduce the risk of hospitalization for HF in diabetic patients. Nevertheless, the molecular mechanisms by which this agent provides cardioprotection remain unclear.

AIM

To investigate the effects of empagliflozin on high glucose (HG)-induced oxidative stress and cardiomyocyte apoptosis and the underlying molecular mechanism.

METHODS

Twelve-week-old db/db mice and primary cardiomyocytes from neonatal rats stimulated with HG (30 mmol/L) were separately employed as in vivo and in vitro models. Echocardiography was used to evaluate cardiac function. Flow cytometry and TdT-mediated dUTP-biotin nick end labeling staining were used to assess apoptosis in myocardial cells. Mitochondrial function was assessed by cellular ATP levels and changes in mitochondrial membrane potential. Furthermore, intracellular reactive oxygen species production and superoxide dismutase activity were analyzed. Real-time quantitative PCR was used to analyze Bax and Bcl-2 mRNA expression. Western blot analysis was used to measure the phosphorylation of AMP-activated protein kinase (AMPK) and myosin phosphatase target subunit 1 (MYPT1), as well as the peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) and active caspase-3 protein levels.

RESULTS

In the in vivo experiment, db/db mice developed DCM. However, the treatment of db/db mice with empagliflozin (10 mg/kg/d) for 8 wk substantially enhanced cardiac function and significantly reduced myocardial apoptosis, accompanied by an increase in the phosphorylation of AMPK and PGC-1α protein levels, as well as a decrease in the phosphorylation of MYPT1 in the heart. In the in vitro experiment, the findings indicate that treatment of cardiomyocytes with empagliflozin (10 μM) or fasudil (FA) (a ROCK inhibitor, 100 μM) or overexpression of PGC-1α significantly attenuated HG-induced mitochondrial injury, oxidative stress, and cardiomyocyte apoptosis. However, the above effects were partly reversed by the addition of compound C (CC). In cells exposed to HG, empagliflozin treatment increased the protein levels of p-AMPK and PGC-1α protein while decreasing phosphorylated MYPT1 levels, and these changes were mitigated by the addition of CC. Adding FA and overexpressing PGC-1α in cells exposed to HG substantially increased PGC-1α protein levels. In addition, no sodium-glucose cotransporter (SGLT)2 protein expression was detected in cardiomyocytes.

CONCLUSION

Empagliflozin partially achieves anti-oxidative stress and anti-apoptotic effects on cardiomyocytes under HG conditions by activating AMPK/PGC-1α and suppressing of the RhoA/ROCK pathway independent of SGLT2.

Canagliflozin ameliorates ulcerative colitis via regulation of TLR4/MAPK/NF-κB and Nrf2/PPAR-γ/SIRT1 signaling pathways

Ulcerative colitis (UC) is one of the most common subtypes of inflammatory bowel disease (IBD) that affects the colon and is characterized by severe intestinal inflammation. Canagliflozin is a widely used antihyperglycemic agent, a sodium-glucose cotransporter-2 (SGLT2) inhibitor that enhances urinary glucose excretion. This study aims to provide insights into the potential benefits of canagliflozin as a treatment for UC by addressing possible cellular signals. Acetic acid (AA; 4% v/v) was administered intrarectally to induce colitis. Canagliflozin is given orally at a dose of 10 mg/kg/day. Canagliflozin attenuates inflammation in AA-induced colitis, evidenced by significant and dose-dependently downregulation of p38 MAPK, NF-κB-p65, IKK, IRF3, and NADPH-oxidase as well as colonic levels of IL-6 and IL-1β and MPO enzymatic activity. Canagliflozin mitigates colonic oxidative stress by decreasing MDA content and restoring SOD enzymatic activities and GSH levels mediated by co-activating of Nrf2, PPARγ, and SIRT1 pathways. Moreover, an in-silico study confirmed that canagliflozin was specific to all target proteins in this study. Canagliflozin's binding affinity with its target proteins indicates and confirms its effectiveness in regulating these pathways. Also, network pharmacology analysis supported that canagliflozin potently attenuates UC via a multi-target and multi-pathway approach.

Functional study and epigenetic targets analyses of SIRT1 in intramuscular preadipocytes via ChIP-seq and mRNA-seq

The SIRT1 epigenetic regulator is involved in hepatic lipid homoeostasis. However, the role of SIRT1 in regulating intramuscular fat deposition as well as the pathways and potential epigenetic targets involved remain unknown. Herein, we investigate SIRT1 function, its genome-wide epigenetic target profile, and transcriptomic changes under SIRT1 overexpression during yak intramuscular preadipocytes differentiation. To this end, we analysed the relationship between SIRT1 and intramuscular fat content as well as lipid metabolism-related genes in longissimus dorsi tissue. We found that SIRT1 expression negatively correlates with intramuscular fat content as well as with the expression of genes related to lipid synthesis, while positively correlating with that of fatty acid oxidation-involved genes. SIRT1 overexpression in intramuscular preadipocytes significantly reduced adipose differentiation marker expression, intracellular triacylglycerol content, and lipid deposition. Chromatin immunoprecipitation coupled with high-throughput sequencing of H3K4ac (a known direct target of SIRT1) and high-throughput mRNA sequencing results revealed that SIRT1 may regulate intramuscular fat deposition via three potential new transcription factors (NRF1, NKX3.1, and EGR1) and four genes (MAPK1, RXRA, AGPAT1, and HADH) implicated in protein processing within the endoplasmic reticulum pathway and the MAPK signalling pathway in yaks. Our study provides novel insights into the role of SIRT1 in regulating yak intramuscular fat deposition and may help clarify the mechanistic determinants of yak meat characteristics.

Targeting mitochondrial quality control for diabetic cardiomyopathy: Therapeutic potential of hypoglycemic drugs

Diabetic cardiomyopathy is a chronic cardiovascular complication caused by diabetes that is characterized by changes in myocardial structure and function, ultimately leading to heart failure and even death. Mitochondria serve as the provider of energy to cardiomyocytes, and mitochondrial dysfunction plays a central role in the development of diabetic cardiomyopathy. In response to a series of pathological changes caused by mitochondrial dysfunction, the mitochondrial quality control system is activated. The mitochondrial quality control system (including mitochondrial biogenesis, fusion and fission, and mitophagy) is core to maintaining the normal structure of mitochondria and performing their normal physiological functions. However, mitochondrial quality control is abnormal in diabetic cardiomyopathy, resulting in insufficient mitochondrial fusion and excessive fission within the cardiomyocyte, and fragmented mitochondria are not phagocytosed in a timely manner, accumulating within the cardiomyocyte resulting in cardiomyocyte injury. Currently, there is no specific therapy or prevention for diabetic cardiomyopathy, and glycemic control remains the mainstay. In this review, we first elucidate the pathogenesis of diabetic cardiomyopathy and explore the link between pathological mitochondrial quality control and the development of diabetic cardiomyopathy. Then, we summarize how clinically used hypoglycemic agents (including sodium-glucose cotransport protein 2 inhibitions, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, thiazolidinediones, metformin, and α-glucosidase inhibitors) exert cardioprotective effects to treat and prevent diabetic cardiomyopathy by targeting the mitochondrial quality control system. In addition, the mechanisms of complementary alternative therapies, such as active ingredients of traditional Chinese medicine, exercise, and lifestyle, targeting mitochondrial quality control for the treatment of diabetic cardiomyopathy are also added, which lays the foundation for the excavation of new diabetic cardioprotective drugs.

A Mitochondrial Nanoguard Modulates Redox Homeostasis and Bioenergy Metabolism in Diabetic Peripheral Neuropathy

As a major late complication of diabetes, diabetic peripheral neuropathy (DPN) is the primary reason for amputation. Nevertheless, there are no wonder drugs available. Regulating dysfunctional mitochondria is a key therapeutic target for DPN. Resveratrol (RSV) is widely proven to guard mitochondria, yet the unsatisfactory bioavailability restricts its clinical application. Tetrahedral framework nucleic acids (tFNAs) are promising carriers due to their excellent cell entrance efficiency, biological safety, and structure editability. Here, RSV was intercalated into tFNAs to form the tFNAs-RSV complexes. tFNAs-RSV achieved enhanced stability, bioavailability, and biocompatibility compared with tFNAs and RSV alone. With its treatment, reactive oxygen species (ROS) production was minimized and reductases were activated in an in vitro model of DPN. Besides, respiratory function and adenosine triphosphate (ATP) production were enhanced. tFNAs-RSV also exhibited favorable therapeutic effects on sensory dysfunction, neurovascular deterioration, demyelination, and neuroapoptosis in DPN mice. Metabolomics analysis revealed that redox regulation and energy metabolism were two principal mechanisms that were impacted during the process. Comprehensive inspections indicated that tFNAs-RSV inhibited nitrosation and oxidation and activated reductase and respiratory chain. In sum, tFNAs-RSV served as a mitochondrial nanoguard (mito-guard), representing a viable drilling target for clinical drug development of DPN.

SIRT1 mediates the inhibitory effect of Dapagliflozin on EndMT by inhibiting the acetylation of endothelium Notch1

BACKGROUND

Endothelial-mesenchymal transition (EndMT) plays a crucial role in promoting myocardial fibrosis and exacerbating cardiac dysfunction. Dapagliflozin (DAPA) is a sodium-glucose-linked transporter 2 (SGLT-2) inhibitor that has been shown to improve cardiac function in non-diabetic patients with heart failure (HF). However, the precise mechanisms by which DAPA exerts its beneficial effects are yet to be fully elucidated.

METHODS

Isoproterenol (ISO) was used to generate a HF model in mice. For in vitro experiments, we used TGF-β1-stimulated human umbilical vein endothelial cells (HUVECs) and mouse aortic endothelial cells (MAECs).

RESULTS

Both our in vivo and in vitro results showed that EndMT occurred with decreased SIRT1 (NAD+-dependent deacetylase) protein expression, which could be reversed by DAPA therapy. We found that the protective effect of DAPA was significantly impaired upon SIRT1 inhibition. Mechanistically, we observed that SIRT1 phosphorylation, a required modification for its ubiquitination and degradation, was reduced by DAPA treatment, which induces the nucleus translocation of SIRT1 and promotes its binding to the active intracellular domain of Notch1 (NICD). This interaction led to the deacetylation and degradation of NICD, and the subsequent inactivation of the Notch1 signaling pathway which contributes to ameliorating EndMT.

CONCLUSIONS

Our study revealed that DAPA can attenuate EndMT induced by ISO in non-diabetic HF mice. This beneficial effect is achieved through SIRT1-mediated deacetylation and degradation of NICD. Our findings provide greater insight into the underlying mechanisms of the therapeutic effects of DAPA in non-diabetic HF.