GSK-3α-BNIP3 axis promotes mitophagy in human cardiomyocytes under hypoxia.

Dysregulated autophagy/mitophagy is one of the major causes of cardiac injury in ischemic conditions. Glycogen synthase kinase-3alpha (GSK-3α) has been shown to play a crucial role in the pathophysiology of cardiac diseases. However, the precise role of GSK-3α in cardiac mitophagy remains unknown. Herein, we investigated the role of GSK-3α in cardiac mitophagy by employing AC16 human cardiomyocytes under the condition of acute hypoxia. We observed that the gain-of-GSK-3α function profoundly induced mitophagy in the AC16 cardiomyocytes post-hypoxia. Moreover, GSK-3α overexpression led to increased ROS generation and mitochondrial dysfunction in cardiomyocytes, accompanied by enhanced mitophagy displayed by increased mt-mKeima intensity under hypoxia. Mechanistically, we identified that GSK-3α promotes mitophagy through upregulation of BNIP3, caused by GSK-3α-mediated increase in expression of HIF-1α and FOXO3a in cardiomyocytes post-hypoxia. Moreover, GSK-3α displayed a physical interaction with BNIP3 and, inhibited PINK1 and Parkin recruitment to mitochondria was observed specifically under hypoxia. Taken together, we identified a novel mechanism of mitophagy in human cardiomyocytes. GSK-3α promotes mitochondrial dysfunction and regulates FOXO3a -mediated BNIP3 overexpression in cardiomyocytes to facilitate mitophagy following hypoxia. An interaction between GSK-3α and BNIP3 suggests a role of GSK-3α in BNIP3 recruitment to the mitochondrial membrane where it enhances mitophagy in stressed cardiomyocytes independent of the PINK1/Parkin.

Natural compound screening predicts novel GSK-3 isoform-specific inhibitors.

Glycogen synthase kinase-3 (GSK-3) plays important roles in the pathogenesis of cardiovascular, metabolic, neurological disorders and cancer. Isoform-specific loss of either GSK-3α or GSK-3ß often provides cytoprotective effects under such clinical conditions. However, available synthetic small molecule inhibitors are relatively non-specific, and their chronic use may lead to adverse effects. Therefore, screening for natural compound inhibitors to identify the isoform-specific inhibitors may provide improved clinical utility. Here, we screened 70 natural compounds to identify novel natural GSK-3 inhibitors employing comprehensive in silico and biochemical approaches. Molecular docking and pharmacokinetics analysis identified two natural compounds Psoralidin and Rosmarinic acid as potential GSK-3 inhibitors. Specifically, Psoralidin and Rosmarinic acid exhibited the highest binding affinities for GSK-3α and GSK-3ß, respectively. Consistent with in silico findings, the kinase assay-driven IC50 revealed superior inhibitory effects of Psoralidin against GSK-3α (IC50 = 2.26 µM) vs. GSK-3ß (IC50 = 4.23 µM) while Rosmarinic acid was found to be more potent against GSK-3ß (IC50 = 2.24 µM) than GSK-3α (IC50 = 5.14 µM). Taken together, these studies show that the identified natural compounds may serve as GSK-3 inhibitors with Psoralidin serving as a better inhibitor for GSK-3α and Rosmarinic for GSK-3ß isoform, respectively. Further characterization employing in vitro and preclinical models will be required to test the utility of these compounds as GSK-3 inhibitors for cardiometabolic and neurological disorders and cancers.

Prospects of Plant Derived Bioactive Compounds as Nanoparticles for Biotechnological Applications.

Nanoparticles bestow beneficial impacts on plants, specifically in increasing photosynthetic capacity and germination rate, pesticide delivery, managing pathogenicity and enhancing nutrient supply. The nanoparticles produced from the medicinal plant extracts are identified as an exceptional applicant in nanomedicine, cosmetics, and agriculture for the treatment of diseases as antimicrobial, antioxidant and anticancer agents, etc. Plant extracts actually have bioactive metabolites that provide therapeutic potential against a variety of diseases. Herein, we review the production of bioactive compounds from leaves, roots, seeds, flowers and stems. We further summarize the different methods for obtaining plant extracts and the green technologies for the synthesis of nanoparticles of plant derived bioactive compounds. Biotechnological aspects of these synthesized nanoparticles are also added here as highlights of this review. Overall, plant derived nanoparticles provide an alternative to conventional approaches for drug delivery as well and present exciting opportunities for future research on novel areas.

Malignance-restriction activity exhibited by bioactive compounds of selected actinobacteria as silver nanoparticles against A549 lung cancer cell lines.

This article deals with the antibacterial and anticancer potential of secondary metabolites produced by actinomycetes also reported as actinobacteria, Microbacterium proteolyticum (MN560041), and Streptomycetes rochei, where preliminary studies were done with the well diffusion method. These actinobacteria's silver nanoparticles were synthesized and characterized using transmission electron microscopy (TEM) and UV-Visible spectroscopy. Anticancer was measured using the MTT test, reactive oxygen species (ROS) generation measured with DCFDA, mitochondrial membrane potential (MMP) measurement, and DAPI fluorescence intensity activity was measured in treated and non-treated cancerous cells. The IC50 value for 5-FU (a), LA2(O) (b), LA2(R) (c), LA2(ON) (d), and LA2(RN) (e) was obtained at 3.91 µg/mL (52.73% cell viability), 56.12 µg/mL (52.35% cell viability), 44.90 µg/mL (52.3% cell viability), 3.45 µg/mL (50.25% cell viability), and 8.05 µg/mL (48.72% cell viability), respectively. TEM micrographs revealed discrete, well-separated AgNPs particles of size 7.88 ± 2 to 12.86 ± 0.24 nm. Gas chromatography-mass spectrometry was also performed to detect the compounds in bioactive metabolites where n-hexadecanoic acid was obtained as the most significant one. MTT test showed a substantial decline in A549 cell viability (up to 48.72%), 2.75-fold increase in ROS generation was noticed in comparison to untreated A549 lung cancer cells when measured with DCFDA. A total of 0.31-fold decrease in MMP and 1.74-fold increase in DAPI fluorescence intensity compared to untreated A549 lung cancer cells suggests that the synthesized nanoparticles promote apoptosis in cancerous cells. Our findings suggests that the secondary metabolites of M. proteolyticum and S. rochei in nanoparticle form can be used as a significant compound against lung cancers.

Targeting inflammatory signaling pathways with SGLT2 inhibitors: Insights into cardiovascular health and cardiac cell improvement.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have attracted significant attention for their broader therapeutic impact beyond simply controlling blood sugar levels, particularly in their ability to influence inflammatory pathways. This review delves into the anti-inflammatory properties of SGLT2 inhibitors, with a specific focus on canagliflozin, empagliflozin, and dapagliflozin. One of the key mechanisms through which SGLT2 inhibitors exert their anti-inflammatory effects is by activating AMP-activated protein kinase (AMPK), a crucial regulator of both cellular energy balance and inflammation. Activation of AMPK by these inhibitors leads to the suppression of pro-inflammatory pathways and a decrease in inflammatory mediators. Notably, SGLT2 inhibitors have demonstrated the ability to inhibit the release of cytokines in an AMPK-dependent manner, underscoring their direct influence on inflammatory signaling. Beyond AMPK activation, SGLT2 inhibitors also modulate several other inflammatory pathways, including the NLRP3 inflammasome, expression of Toll-like receptor 4 (TLR-4), and activation of NF-κB (Nuclear factor kappa B). This multifaceted approach contributes to their efficacy in reducing inflammation and managing associated complications in conditions such as diabetes and cardiovascular disorders. Several human and animal studies provide support for the anti-inflammatory effects of SGLT2 inhibitors, demonstrating protective effects on various cardiac cells. Additionally, these inhibitors exhibit direct anti-inflammatory effects by modulating immune cells. Overall, SGLT2 inhibitors emerge as promising therapeutic agents for targeting inflammation in a range of pathological conditions. Further research, particularly focusing on the molecular-level pathways of inflammation, is necessary to fully understand their mechanisms of action and optimize their therapeutic potential in inflammatory diseases.

Transcriptome-wide quantitative profiling of PUS7-dependent pseudouridylation by nanopore direct long read RNA sequencing.

Pseudouridylation is a prevalent post-transcriptional RNA modification that impacts many aspects of RNA biology and function. The conversion of uridine to pseudouridine (Ψ) is catalyzed by the family of pseudouridine synthases (PUSs). Development of robust methods to determine PUS-dependent regulation of Ψ location and stoichiometry in low abundant mRNA is essential for biological and functional understanding of pseudouridylation. Here, we present a framework, NanoPsiPy, for identifying Ψ sites and quantify their levels in poly-A RNA at single-nucleotide resolution using direct RNA long-read Nanopore sequencing, based on the observation that Ψ can cause characteristic U-to-C basecalling errors in Nanopore direct RNA sequencing data. Our method was able to detect low and high stoichiometric Ψ sites in human mRNA. We validated our method by transcriptome-wide quantitative profiling of PUS7-dependent Ψ sites in poly-A RNA from a MYCN -amplified neuroblastoma cell line. We identified 8,625 PUS7-dependent Ψ sites in 1,246 mRNAs that encode proteins involved primarily in ribosome biogenesis, translation, and mitochondrial energy metabolism. Our work provides the first example of using direct RNA long-read Nanopore sequencing for transcriptome-wide quantitative profiling of mRNA pseudouridylation regulated by a PUS. We envision that our method will facilitate functional interrogation of PUSs in biological and pathological processes.