Berberine mitigates hepatic insulin resistance by enhancing mitochondrial architecture via the SIRT1/Opa1 signalling pathway

Leptin attenuates diabetic cardiomyopathy-induced cardiac remodeling via regulating cGAS/STING signaling and Opa1-mediated mitochondrial fusion

PURPOSE

This investigation seeks to elucidate the contribution of leptin to the pathogenesis of diabetic cardiomyopathy (DCM).

METHODS

Mice were rendered diabetic through the administration of streptozotocin (STZ). Leptin was delivered via subcutaneously implanted osmotic pumps. Assessments of cardiac performance, hypertrophy, and fibrosis were conducted using echocardiography, Hematoxylin and Eosin (H&E), Wheat Germ Agglutinin (WGA), and Masson trichrome staining. Myocardial apoptosis and oxidative stress were quantified through TUNEL assay and biochemical markers of oxidative stress, including Malondialdehyde (MDA), 4-Hydroxynonenal (4-HNE), and 3-Nitrotyrosine (3NT). Mitochondrial structure was examined using Transmission Electron Microscopy (TEM). Primary neonatal cardiomyocytes were subjected to high glucose (HG) conditions. The fluorescent indicators MitoTracker Green and MitoSOX Red were employed to evaluate mitochondrial morphology and function within the cardiomyocytes.

RESULTS

Mice with diabetes displayed marked cardiac hypertrophy and fibrosis, as indicated by H&E, WGA, and Masson staining. The administration of leptin significantly mitigated the cardiac pathological manifestations in diabetic mice. Leptin increased the expression of Opa1 and enhanced mitochondrial fusion and function in cardiomyocytes exposed to HG. The cGAS/STING signaling pathway may serve as a pivotal intermediary for leptin to facilitate Opa1-driven mitochondrial fusion.

CONCLUSIONS

Leptin appears to safeguard against hyperglycemia-induced mitochondrial oxidative damage and DCM by modulating the cGAS/STING signaling cascade and Opa1-mediated mitochondrial fusion. These results propose that leptin could be a promising agent for promoting mitochondrial fusion and preventing diabetes-associated cardiac pathologies.

Mito-TEMPO Mitigates Fibromyalgia Induced by Reserpine in Rats: Orchestration Between SIRT1, Mitochondrial Dynamics, Endoplasmic Reticulum and miRNA-320

Fibromyalgia (FM) is a chronic disorder that lacks both well-defined underlying causes and effective treatments. Mito-TEMPO (MIT) is a mitochondrial-specific antioxidant that has demonstrated benefits in many cancerous, renal, cardiovascular, and neurodegenerative disorders. However, the therapeutic effect of MIT on FM remains ambiguous. The objective of the current work is to illuminate the use of MIT for FM and its prospective mechanisms. Here, we used the FM rat model induced by three days of subcutaneous reserpine injection (1 mg/kg) and examined the role of MIT on SIRT1 activation and other implicated molecular pathways. Behavioral tests showed that MIT (0.7 mg/kg) can effectively alleviate the locomotor, nociceptive, and depressive-like behaviors in reserpinized rats, an effect that simultaneously reconciles the balance of monoamines in the rat brain. Western blot analysis showed that MIT up-regulates SIRT1 and improves the expression of mitochondrial dynamics proteins (DRP1 and OPA1) and the endoplasmic reticulum protein (CHOP). Furthermore, MIT treatment significantly enhanced the SOD and CAT activities and decreased the brain contents of NF-κB, TNF-α, and BAX, but significantly enriching the Bcl-2 content. Lastly, MIT treatment significantly reduced the genetic expression of miRNA-320 following RES treatment. All the measured parameters showed a significant correlation with SIRT1 expression. Our results suggest that MIT provides antioxidant, anti-apoptotic, and anti-inflammatory impacts on the FM rat model, with proposed mechanisms involved activating the SIRT1 pathway to regulate mitochondrial dynamics, endoplasmic reticulum stress, as well as miRNA-320. Thus, MIT has the potential to be an effectual drug candidate for FM treatment.

SIRT1 and its SUMOylation attenuate hyperoxia-induced lung injury by improving mitochondrial biogenesis and fusion

OBJECTIVE

To investigate the role of silencing information regulator 2 related enzyme 1 (SIRT1) and its small ubiquitin-like modifier (SUMO) modification (SUMOylation) in hyperoxia lung injury in preterm infants.

METHODS

The roles of SIRT1 and its SUMOylation in hyperoxia-induced damage to HAECs were explored from the cellular level using CCK-8, MTT, scratch assay, reactive oxygen species (ROS), Mito SOX™, BeyoClick™ EdU-488, immunofluorescence and Western-blot, mitochondrial membrane potential, malondialdehyde and superoxide dismutase assays, MitoTracker® Red CMXRos, transmission electron microscopy, and SIRT1 activity assay. Type II alveolar epithelial cell-specific knockout SENP1 mice were constructed. The role of SUMOylation of SIRT1 in hyperoxia lung injury in mice was explored in vivo by HE staining, immunohistochemistry, immunofluorescence, Western-blot and transmission electron microscopy.

RESULTS

(1) Hyperoxia increased ROS in HAECs and decreased cell proliferation levels and survival, as well as reduced the expression of peroxisome-proliferator-γ coactivator-1α (PGC-1α), nuclear respiratory factor 1 (NRF1), mitochondrial transcription factor A (TFAM), optic atrophy protein 1 (OPA1), mitofusins 1 (MFN1), and mitofusins 2 (MFN2) proteins. (2) N-Acetylcysteine inhibited SIRT1 nucleoplasmic shuttling and reversed the hyperoxia-induced decrease in SUMO1 and increase in SENP1. (3) SRT1720 reversed the hyperoxia-induced decrease of PGC-1α, NRF1, TFAM, MFN1, MFN2 and OPA1 proteins. (4) Overexpression of SUMO1 increased total SIRT1 and nuclear SIRT1 but decreased cytoplasmic SIRT1 protein expression levels, attenuated hyperoxia-induced mitochondrial injury. (5) On day 14 of hyperoxia exposure, type II alveolar epithelial cell-specific knockout SENP1 mice showed reduced lung injury, increased lung tissue total SIRT1 and nuclear SIRT1 but decreased cytoplasmic SIRT1 protein expression, and reduced mitochondrial injury.

CONCLUSION

Hyperoxia increases ROS levels to decrease SIRT1 and SUMO1 levels, thereby inhibiting mitochondrial biogenesis and fusion, and promotion of SIRT1 and its SUMOylation improves mitochondrial biogenesis and fusion, thereby attenuating hyperoxia lung injury.

Ginsenoside Rb1 and berberine synergistically protect against type 2 diabetes mellitus via GDF15/HAMP pathway throughout the liver lobules: Insights from spatial transcriptomics analysis

Type 2 diabetes mellitus (T2DM) is a significant public health issue with high morbidity and mortality. Ginsenoside Rb1 (Rb1) and berberine (BBR), the main bioactive compounds of Panax ginseng and Coptis chinensis, respectively, are known for their hypoglycemic effects. Nevertheless, the synergistic effects and underlying mechanism of Rb1 and BBR on T2DM remain unclear. In this study, we utilized a leptin receptor-deficient (db/db) mouse model to investigate the protective effects of their combination treatment. Our findings demonstrated that the combined use of Rb1 and BBR at a 1:4 ratio had more pronounced effects than the first-line anti-diabetic drug metformin on reducing the weight ratio of white adipose tissue, ameliorating insulin resistance, and improving glucose and lipid metabolism. Using spatial transcriptomics, we revealed that metformin treatment improved gluconeogenesis and lipogenesis only in the periportal zone, while the combination treatment induced improvements throughout the liver lobule, with distinct key targets across different zones, thus underscoring a more comprehensive modulation of hepatic metabolism. This may be the key reason why this combination therapy demonstrated superior protective effects against T2DM. Additionally, the reversed expression of the key callback gene hepcidin (HAMP) and its regulator growth differentiation factor 15 (GDF15) following the combination therapy across all zones, along with validation experiments, further suggested that GDF15/HAMP pathway might be a key mechanism underlying the beneficial effects of Rb1 and BBR against T2DM. This study also indicates a path toward innovative drug cocktails for treating T2DM, offering a holistic approach to regulate the entire liver lobule metabolism.

Dulaglutide restores endothelial progenitor cell levels in diabetic mice and mitigates high glucose-induced endothelial injury through SIRT1-mediated mitochondrial fission

Type 2 diabetes mellitus (T2DM) significantly impairs the functionality and number of endothelial progenitor cells (EPCs) and resident endothelial cells, critical for vascular repair and regeneration, exacerbating the risk of vascular complications. GLP-1 receptor agonists, like dulaglutide, have emerged as promising therapeutic agents due to their multifaceted effects, including the enhancement of EPC activity and protection of endothelial cells. This study investigates dulaglutide's effects on peripheral blood levels of CD34+ and CD133+ cells in a mouse model of lower limb ischemia and its protective mechanisms against high-glucose-induced damage in endothelial cells. Results demonstrated that dulaglutide significantly improves blood flow, reduces tissue damage and inflammation in ischemic limbs, and enhances glycemic control. Furthermore, dulaglutide alleviated high-glucose-induced endothelial cell damage, evident from improved tube formation, reduced reactive oxygen species accumulation, and restored endothelial junction integrity. Mechanistically, dulaglutide mitigated mitochondrial fission in endothelial cells under high-glucose conditions, partly through maintaining SIRT1 expression, which is crucial for mitochondrial dynamics. This study reveals the potential of dulaglutide as a therapeutic option for vascular complications in T2DM patients, highlighting its role in improving endothelial function and mitochondrial integrity.

TGF-β3 mediates mitochondrial dynamics through the p-Smad3/AMPK pathway

It is well recognized that mitochondrial dynamics plays a vital role in cartilage physiology. Any perturbation in mitochondrial dynamics could cause disorders in cartilage metabolism and even lead to the occurrence of cartilage diseases such as osteoarthritis (OA). TGF-β3, as an important growth factor that appears in the joints of OA disease, shows its great potential in chondrocyte growth and metabolism. Nevertheless, the role of TGF-β3 on mitochondrial dynamics is still not well understood. Here we aimed to investigate the effect of TGF-β3 on mitochondrial dynamics of chondrocytes and reveal its underlying bio-mechanism. By using transmission electron microscopy (TEM) for the number and morphology of mitochondria, western blotting for the protein expressions, immunofluorescence for the cytoplasmic distributions of proteins, and RNA sequencing for the transcriptome changes related to mitochondrial dynamics. We found that TGF-β3 could increase the number of mitochondria in chondrocytes. TGF-β3-enhanced mitochondrial number was via promoting the mitochondrial fission. The mitochondrial fission induced by TGF-β3 was mediated by AMPK signaling. TGF-β3 activated canonical p-Smad3 signaling and resultantly mediated AMPK-induced mitochondrial fission. Taken together, these results elucidate an understanding of the role of TGF-β3 on mitochondrial dynamics in chondrocytes and provide potential cues for therapeutic strategies in cartilage injury and OA disease in terms of energy metabolism.

Study on the neuroprotective effect of Zhimu-Huangbo extract on mitochondrial dysfunction in HT22 cells induced by D-galactose by promoting mitochondrial autophagy

ETHNOPHARMACOLOGICAL RELEVANCE

Zhimu-Huangbo (ZB) herb pair is a common prescription drug used by physicians of all dynasties, and has significant neuroprotective effect, such as the ZB can significantly promote neuronal cell regeneration, repair neuronal damage, and improve cognitive disorders. However, its ingredients are urgently needed to be identified and mechanisms is remained unclear.

AIM OF THE STUDY

Using ultra performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS), the study of neuroprotective mechanism of Zhimu-Huangbo extract (ZBE) is investigated, and the network pharmacology technology and experimental validation is also performed.

MATERIAL AND METHODS

Firstly, UPLC-Q-TOF-MS technology was used to characterize the chemical components contained in the ZBE. After that, the TCMSP database and the Swiss Target Prediction method were used to search for potential target genes for ZBE compounds. At the same time, the OMIM and GeneCards disease databases were used to search for Alzheimer's disease (AD) targets and expanded with the GEO database. Then, GO and KEGG enrichment analysis was performed using OECloud tools. Subsequently, the potential mechanism of ZBE therapeutic AD predicted by network pharmacological analysis was experimentally studied and verified in vitro.

RESULTS

In the UPLC-Q-TOF-MS analysis of the ZBE, a total of 39 compounds were characterized including Neomangiferin, Oxyberberine, Timosaponin D, Berberine, Timosaponin A-III, Anemarsaponin E, Timosaponin A-I, Smilagenin and so on. A total of 831 potential targets and 13995 AD-related target genes were screened. A further analysis revealed the number of common targets between ZBE and AD is 698. Through GO and KEGG enrichment analysis, we found that ZBE's anti-AD targets were significantly enriched in autophagy and mitochondrial autophagy related pathways. The results of cell experiments also confirmed that ZBE can promote mitochondrial autophagy induced by D-galactose (D-gal) HT22 cells through the PTEN-induced kinase 1/Parkin (PINK1/Parkin) pathway.

CONCLUSION

ZBE can promote autophagy of mitochondria and play a protective role on damaged neurons.

Recent Advances of Mitochondrial Alterations in Alzheimer's Disease: A Perspective of Mitochondrial Basic Events

Alzheimer's disease (AD) is one of the most common neurodegenerative disorders and is characterized by a decrease in learning capacity, memory loss and behavioral changes. In addition to the well-recognized amyloid-β cascade hypothesis and hyperphosphorylated Tau hypothesis, accumulating evidence has led to the proposal of the mitochondrial dysfunction hypothesis as the primary etiology of AD. However, the predominant molecular mechanisms underlying the development and progression of AD have not been fully elucidated. Mitochondrial dysfunction is not only considered an early event in AD pathogenesis but is also involved in the whole course of the disease, with numerous pathophysiological processes, including disordered energy metabolism, Ca2+ homeostasis dysfunction and hyperactive oxidative stress. In the current review, we have integrated emerging evidence to summarize the main mitochondrial alterations- bioenergetic metabolism, mitochondrial inheritance, mitobiogenesis, fission- fusion dynamics, mitochondrial degradation, and mitochondrial movement- underlying AD pathogenesis; precisely identified the mitochondrial regulators; discussed the potential mechanisms and primary processes; highlighted the leading players; and noted additional incidental signaling pathway changes. This review may help to stimulate research exploring mitochondrial metabolically-oriented neuroprotection strategies in AD therapies, leading to a better understanding of the link between the mitochondrial dysfunction hypothesis and AD pathogenesis.

Advances of berberine against metabolic syndrome-associated kidney disease: Regarding effect and mechanism

The prevalence of metabolic syndrome (MetS) is drastically growing worldwide, resulting in MetS-associated kidney disease. According to traditional theories, preventing blood pressure, lipid, glycose, and obesity and improving insulin resistance (IR), a couple of medications are required for MetS. It not only lowers patients' compliance but also elevates adverse reactions. Accordingly, we attempted to seek answers from complementary and alternative medicine. Ultimately, berberine (BBR) was chosen due to its efficacy and safety on MetS through multi-pathways and multi-targets. The effects and mechanisms of BBR on obesity, IR, diabetic nephropathy, hypertension, hyperlipidemia, and hyperuricemia were elaborated. In addition, the overall properties of BBR and interventions for various kidney diseases were also collected. However, more clinical trials are expected to further identify the beneficial effects of BBR.

Alkaloids as Promising Agents for the Management of Insulin Resistance: A Review

BACKGROUND

Insulin resistance is one of the main factors that lead to the development of type 2 diabetes mellitus (T2DM). The effect of alkaloids on insulin resistance has been extensively examined according to multiple scientific researches.

OBJECTIVE

In this work, we aimed to summarize the interesting results from preclinical and clinical studies that assessed the effects of natural alkaloids (berberine, nigelladine A, piperine, trigonelline, capsaicin, nuciferine, evodiamine, mahanine, and magnoflorine) on impaired insulin sensitivity and worsened insulin resistance, which play a pivotal role in the pathogenesis of type 2 diabetes.

METHODS

In the current review, PubMed, ScienceDirect, Springer, and Google Scholar databases were used. The inclusion criteria were based on the following keywords and phrases: insulin sensitivity, insulin resistance, alkaloids and insulin resistance, alkaloids and type 2 diabetes, mechanisms of action, and alkaloids.

RESULTS

The outcomes reported in this review demonstrated that the selected alkaloids increased insulin sensitivity and reduced insulin resistance in vitro and in vivo evidence, as well as in clinical trials, through improving insulin-signaling transduction mainly in hepatocytes, myocytes, and adipocytes, both at cellular and molecular levels. Insulin signaling components (InsR, IRS-1, PI3K, Akt, etc.), protein kinases and phosphatases, receptors, ion channels, cytokines, adipokines, and microRNAs, are influenced by alkaloids at transcriptional and translational levels, also in terms of function (activity and/or phosphorylation). Multiple perturbations associated with insulin resistance, such as ectopic lipid accumulation, inflammation, ER stress, oxidative stress, mitochondrial dysfunction, gut microbiota dysbiosis, and β-cell failure, are reversed after treatment with alkaloids. Furthermore, various indices and tests are employed to assess insulin resistance, including the Matsuda index, insulin sensitivity index (ISI), oral glucose tolerance test (OGTT), and insulin tolerance test (ITT), which are all enhanced by alkaloids. These improvements extend to fasting blood glucose, fasting insulin, and HbA1c levels as well. Additionally, the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and the Homeostasis Model Assessment of β-cell function (HOMA-β) are recognized as robust markers of insulin sensitivity and β-cell function, and it is noteworthy that alkaloids also lead to improvements in these two markers.

CONCLUSION

Based on the findings of the current review, alkaloids may serve as both preventive and curative agents for metabolic disorders, specifically type 2 diabetes. Nonetheless, there is an urgent need for additional clinical trials to explore the potential benefits of alkaloids in both healthy individuals and those with type 2 diabetes. Additionally, it is crucial to assess any possible side effects and interactions with antidiabetic drugs.