Mechanisms of AMPK in the maintenance of ATP balance during energy metabolism

Metabolic reprogramming: a new option for the treatment of spinal cord injury

Spinal cord injuries impose a notably economic burden on society, mainly because of the severe after-effects they cause. Despite the ongoing development of various therapies for spinal cord injuries, their effectiveness remains unsatisfactory. However, a deeper understanding of metabolism has opened up a new therapeutic opportunity in the form of metabolic reprogramming. In this review, we explore the metabolic changes that occur during spinal cord injuries, their consequences, and the therapeutic tools available for metabolic reprogramming. Normal spinal cord metabolism is characterized by independent cellular metabolism and intercellular metabolic coupling. However, spinal cord injury results in metabolic disorders that include disturbances in glucose metabolism, lipid metabolism, and mitochondrial dysfunction. These metabolic disturbances lead to corresponding pathological changes, including the failure of axonal regeneration, the accumulation of scarring, and the activation of microglia. To rescue spinal cord injury at the metabolic level, potential metabolic reprogramming approaches have emerged, including replenishing metabolic substrates, reconstituting metabolic couplings, and targeting mitochondrial therapies to alter cell fate. The available evidence suggests that metabolic reprogramming holds great promise as a next-generation approach for the treatment of spinal cord injury. To further advance the metabolic treatment of the spinal cord injury, future efforts should focus on a deeper understanding of neurometabolism, the development of more advanced metabolomics technologies, and the design of highly effective metabolic interventions.

Exploring the effect and mechanism of Hippophae rhamnoides L. triterpenoid acids on improving NAFLD based on network pharmacology and experimental validation in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Sea buckthorn (Hippophae rhamnoides L.) is a traditional Chinese medicinal and possesses a rich medical history in terms of treating gastric disorders, sputum and cough and liver injuries in oriental medicinal system. By reason of the complicated chemical constituents, the material basis and potential pharmacological mechanism of sea buckthorn acting on Non-alcoholic fatty liver disease (NAFLD) has not been clearly elucidated.

AIM OF THE STUDY

To explore the pharmacological efficacy and underlying mechanism of sea buckthorn triterpenoid acid enrichment (STE) in the treatment of NAFLD.

MATERIALS AND METHODS

The approaches of Network pharmacology and experiment validation in vitro and in vivo were applied in this study. Firstly, targets of triterpenoid acid compounds and NAFLD were collected from databases. The crucial targets were screened by the construction of protein-protein interaction (PPI) network. Furthermore, the potential signaling pathways and targets affected by STE was predicted by GO together with KEGG enrichment analysis. Finally, the experiment validation was carried out through high-fat feeding NAFLD mice and lipid accumulation HepG2 cell model. Lipids and liver related biochemical indicators were determined, Oil Red O and H&E staining were employed to observe fat accumulation. In addition, the expression levels of proteins of key target and signal pathway anticipated in network pharmacology were detected to elaborated its action mechanism.

RESULTS

A total of 180 intersecting potential targets for enhancing NAFLD with STE were eventually identified. 6 key targets including AKT1, TNF, IL6, INS, JUN, STAT3 and TP53 were further identified and the AMPK-SREBP1 pathway was enriched. Animal experiment result showed that STE treatment could significantly reduce the levels of TG, TC, LDL-C, ALT and AST, increase the levels of HDL-C in serum, and improve lipid accumulation of epididymal fat and liver. The results of the lipid accumulation cell model indicated that STE and key compound oleanolic acid could diminish intracellular lipid levels of TG, TC, LDL-C and number of lipid droplets. Western blot results showed that the above beneficial effects could be achieved by regulating the expression of p-AMPK/AMPK, SREBP1, FAS, ACC, SCD protein.

CONCLUSION

This study confirmed the effect of STE on improving NAFLD and the potential action mechanism was involved in the regulation of the AMPK-SREBP1 pathway.

Exploring the Effects of Whole Food-Based Dragon Fruit on Metabolic Disorders in High-Fat Diet-Induced Mice

SCOPE

Metabolic syndrome (MetS) significantly contributes to premature mortality, with obesity being a major risk factor. Dragon fruit, cultivated globally, exhibits bioactivity in preventing obesity-related diseases. Traditional studies using organic solvents for extraction do not align with actual consumption patterns.

METHOD AND RESULTS

This study evaluates whole red dragon fruit's effectiveness in ameliorating metabolic disorders using a high-fat diet-induced obesity model in mice for 20 weeks. The experimental groups include the supernatant (RS), precipitate (RP), and pomace (PO) of red dragon fruit juice, compared to the supernatant of white dragon fruit juice (WS). The study finds that dragon fruit extracts reduced adipose tissue weight, body fat percentage, pro-inflammatory cytokines, and improved blood lipid profiles. RP is the most effective, reducing body weight by 4.33 g, improving lipid metabolism and glucose homeostasis, and altering gut microbiota to enhance beneficial bacteria and short-chain fatty acids. RP's efficacy in preventing MetS and obesity is attributed to its bioactive components.

CONCLUSION

These findings advocate for using whole fruits in developing functional products, amplifying the agricultural economic value of red dragon fruit.

Docosahexaenoic acid supplementation during porcine oocyte in vitro maturation improves oocyte quality and embryonic development by enhancing the homeostasis of energy metabolism

Although supplementation with docosahexaenoic acid (DHA) during porcine oocyte IVM is well-established, the available data are limited due to the lack of consistency. Moreover, to our knowledge, the anti-oxidant effects of DHA on porcine oocytes have not been reported. Hence, this study aimed to examine the effects of DHA supplementation on the regulation of energy metabolism during porcine oocyte maturation to improve oocyte maturation and embryonic development. By supplementing the IVM medium with various DHA concentrations, 25 μM DHA was identified as the optimal concentration which improved intraoocyte glutathione content and enhanced embryonic development after parthenogenesis. Compared to embryos derived from the control group, those derived from SCNT or IVF showed significantly improved blastocyst formation upon DHA supplementation during IVM. In addition, various transcription factors associated with oocyte development and apoptosis in mature oocytes were beneficially regulated in the DHA-treated oocytes. Moreover, DHA improved the AMP-activated protein kinase (AMPK)-regulatory ability of porcine oocytes and ameliorated nuclear maturation and embryonic development, which were decreased by artificially downregulating AMPK. To our knowledge, this is the first study to examine the effects of DHA as an AMPK regulator on oocyte maturation and embryo development in pigs. Furthermore, DHA addition to the IVM medium upregulated the relative expression of genes associated with mitochondrial potential and lipid metabolism. Therefore, the membrane potential of mitochondria (evaluated based on the JC-1 aggregate/JC-1 monomer ratio) and the levels of fatty acids and lipid droplets in matured oocytes increased, resulting in increased ATP synthesis. In conclusion, the DHA treatment of porcine oocytes with 25 μM DHA during IVM enhances the homeostasis of energy metabolism by improving mitochondrial function and lipid metabolism, leading to improved quality of matured oocytes and enhanced embryonic developmental potential of in vitro produced (IVP) embryos. Thus, 25 μM DHA supplementation could serve as a tool for improving the quality of IVP embryos. The study findings provide a basis for further research on improving the production efficiency of cloned animals by securing high-quality matured oocytes and enhancing energy metabolism in mammalian oocytes, including those of pigs.

Hypoxia-induced downregulation of RNA m6A protein machinery in the naked mole-rat heart

Naked mole-rats, Heterocephalus glaber, are champion hypoxia-tolerant rodents that live under low oxygen conditions in their subterranean burrows. Detrimental effects of low oxygen can be mitigated through metabolic rate depression (MRD), metabolic reorganization, and global downregulation of nonessential cellular processes. Recent research has progressively implicated epigenetic modifications - rapid, reversible changes to gene expression that do not alter the DNA sequence itself - as major players in implementing and maintaining MRD. N6-adenosine (m6A) methylation is the most prevalent mammalian RNA modification and is responsible for pre-mRNA processing and mRNA export from the nucleus. Hence, m6A -mediated conformational changes alter the cellular fate of transcripts. The present study investigated the role of m6A RNA methylation responses to 24 h of hypoxia exposure in H. glaber cardiac tissue. Total protein levels of m6A writers/readers/erasers, m6A demethylase activity, and total m6A quantification were measured under normoxic vs. hypoxic conditions in H. glaber heart. While there was no change in either demethylase activity or total m6A content, many proteins of the m6A pathway were downregulated during hypoxia. Overall, m6A may not be a signature hypoxia-responsive characteristic in H. glaber heart, but downregulation of the protein machinery involved in m6A cycling points to an alternate biological involvement. Further research will explore other forms of RNA modifications and other epigenetic mechanisms to determine the controls on hypoxia endurance in this subterranean mammal.

Unveiling Potential Targeted Therapeutic Opportunities for Co-Overexpressed Targeting Protein for Xklp2 and Aurora-A Kinase in Lung Adenocarcinoma

Lung adenocarcinoma (LUAD) is one of the most prevalent and leading causes of cancer deaths globally, with limited diagnostic and clinically significant therapeutic targets. Identifying the genes and processes involved in developing and progressing LUAD is crucial for developing effective targeted therapeutics and improving patient outcomes. Therefore, the study aimed to explore the RNA sequencing data of LUAD from The Cancer Genome Atlas (TCGA) and gene expression profile datasets involving GSE10072, GSE31210, and GSE32863 from the Gene Expression Omnibus (GEO) databases. The differential gene expression and the downstream analysis determined clinically significant biomarkers using a network-based approach. These therapeutic targets predominantly enriched the dysregulation of mitotic cell cycle regulation and revealed the co-overexpression of Aurora-A Kinase (AURKA) and Targeting Protein for Xklp2 (TPX2) with high survival risk in LUAD patients. The hydrophobic residues of the AURKA-TPX2 interaction were considered as the target site to block the autophosphorylation of AURKA during the mitotic cell cycle. The tyrosine kinase inhibitor (TKI) dacomitinib demonstrated the strong binding potential to hinder TPX2, shielding the AURKA destabilization. This in silico study lays the foundation for repurposing targeted therapeutic options to impede the Protein-Protein Interactions (PPIs) in LUAD progression and aid in future translational investigations.

Identification of genomic regions associated with fatty acid metabolism across blood, liver, backfat and muscle in pigs

BACKGROUND

The composition and distribution of fatty acids (FA) are important factors determining the quality, flavor, and nutrient value of meat. In addition, FAs synthesized in the body participate in energy metabolism and are involved in different regulatory pathways in the form of signaling molecules or by acting as agonist or antagonist ligands of different nuclear receptors. Finally, synthesis and catabolism of FAs affect adaptive immunity by regulating lymphocyte metabolism. The present study performed genome-wide association studies using FA profiles of blood, liver, backfat and muscle from 432 commercial Duroc pigs.

RESULTS

Twenty-five genomic regions located on 15 Sus scrofa chromosomes (SSC) were detected. Annotation of the quantitative trait locus (QTL) regions identified 49 lipid metabolism-related candidate genes. Among these QTLs, four were identified in more than one tissue. The ratio of C20:4n-6/C20:3n-6 was associated with the region on SSC2 at 7.56-14.26 Mb for backfat, liver, and muscle. Members of the fatty acid desaturase gene cluster (FADS1, FADS2, and FADS3) are the most promising candidate genes in this region. Two QTL regions on SSC14 (103.81-115.64 Mb and 100.91-128.14 Mb) were identified for FA desaturation in backfat and muscle. In addition, two separate regions on SSC9 at 0 - 14.55 Mb and on SSC12 at 0-1.91 Mb were both associated with the same multiple FA traits for backfat, with candidate genes involved in de novo FA synthesis and triacylglycerol (TAG) metabolism, such as DGAT2 and FASN. The ratio C20:0/C18:0 was associated with the region on SSC5 at 64.84-78.32 Mb for backfat. Furthermore, the association of the C16:0 content with the region at 118.92-123.95 Mb on SSC4 was blood specific. Finally, candidate genes involved in de novo lipogenesis regulate T cell differentiation and promote the generation of palmitoleate, an adipokine that alleviates inflammation.

CONCLUSIONS

Several SNPs and candidate genes were associated with lipid metabolism in blood, liver, backfat, and muscle. These results contribute to elucidating the molecular mechanisms implicated in the determination of the FA profile in different pig tissues and can be useful in selection programs that aim to improve health and energy metabolism in pigs.

S-nitrosoglutathione (GSNO) induces necroptotic cell death in K562 cells: Involvement of p73, TSC2 and SIRT1

BACKGROUND

Nitric oxide and Reactive Nitrogen Species are known to effect tumorigenicity. GSNO is one of the main NO carrying signalling moiety in cell. In the current study, we tried to delve into the effect of GSNO induced nitrosative stress in three different myelogenous leukemic K562, U937 and THP-1 cell lines.

METHOD

WST-8 assay was performed to investigate cell viability. RT-PCR and western-blot analysis were done to investigate mRNA and protein expression. Spectrophotometric and fluorimetric assays were done to investigate enzyme activities.

RESULT

We found that GSNO exposure led to reduced cell viability and the mode of cell death in K562 was non apoptotic in nature. GSNO promoted impaired autophagic flux and necroptosis. GSNO treatment heightened phosphorylation of AMPK and TSC2 and inhibited mTOR pathway. We observed increase in NAD+/ NADH ratio following GSNO treatment. Increase in both SIRT1 m-RNA and protein expression was observed. While total SIRT activity remained unaltered. GSNO increased tumor suppressor TAp73/ oncogenic ∆Np73 ratio in K562 cells which was correlated with cell mortality. Surprisingly, GSNO did not alter cellular redox status or redox associated protein expression. However, steep increase in total SNO and PSNO content was observed. Furthermore, inhibition of autophagy, AMPK phosphorylation or SIRT1 exacerbated the effect of GSNO. Altogether our work gives insights into GSNO mediated necroptotic event in K562 cells which can be excavated to develop NO based anticancer therapeutics.

CONCLUSION

Our data suggests that GSNO could induce necroptotic cell death in K562 through mitochondrial dysfunctionality and PTM of different cellular proteins.

Electrospun Poly-l-Lactic Acid Membranes Promote M2 Macrophage Polarization by Regulating the PCK2/AMPK/mTOR Signaling Pathway

Electrospun membranes are widely used in tissue engineering. Regretfully, there is limited research on how its morphological characteristics precisely regulate macrophage activation and immune response. Therefore, electrospun poly-l-lactic acid (PLLA) membranes with different alignments (align and random) and diameters (nanoscale and microscale) are prepared to investigate the effects of different surface morphologies on M2 macrophage polarization. Additionally, transcriptome, proteome, and phosphoproteome sequencings are combined to examine the underlying regulatory mechanisms. The results show that the electrospun PLLA membranes with different surface morphologies have good biocompatibility and can regulate the phenotype and function of macrophages by changing the micromorphology of the matrix surface. Especially, macrophages cultured on the electrospun membranes of the A600 group exhibit higher M2 macrophage polarization than the other three groups. Furthermore, the findings demonstrate that electrospun PLLA membranes enhance AMP-activated protein kinase (AMPK)/ mammalian target of rapamycin (mTOR) signaling activation by upregulating the expression of integrin phosphoenolpyruvate carboxykinase 2 (PCK2), which is critical for M2 macrophage polarization. Taken together, electrospun PLLA membranes promote M2 macrophage polarization by regulating the PCK2/AMPK/mTOR signaling pathway. This research can provide further theoretical bases for scaffold design, immunoregulatory mechanisms, and clinical application based on electrospinning technology in the future.

Exploring the gut microbiota mediated biotransformation of Senecio scandens Buch.-Ham.: Insights from metabolite spectrum with UHPLC-Q-Orbitrap HRMS and bioinformatics analysis of gut microbiota metabolites

Senecio scandens Buch.-Ham., a traditional Chinese medicine commonly used clinically, exhibits various pharmacological properties, including anti-inflammatory, anti-tumor, antiviral, and antibacterial activities. However, its water extracts' chemical components and metabolites are inadequately understood, limiting further research. In this study, the chemical components and metabolism processes of Senecio scandens, both in vivo (plasma, feces, urine, and bile) and in vitro (gut microbiota and liver microsomes), were characterized based on ultra-high performance liquid chromatography coupled with hybrid quadrupole-orbitrap high-resolution mass spectrometry. Additionally, metabolites detectable in fecal samples and intestinal microbiota incubated but absent in liver microsomes were identified as characteristic metabolites of intestinal microbiota. The targets of the characteristic metabolites of intestinal microbiota were collected, followed by exploration of potential pathways through KEGG enrichment analysis. As a result, a total of 133 chemical components were preliminarily identified, including 35 organic acids, 21 alkaloids, 19 flavonoids and their glycosides, 17 phenylpropanoids, 10 jacaranda ketones, and 31 other compounds. Notably, 12 of these were potentially novel compounds. In addition, 39 prototype components in rats and 109 metabolites were identified and characterized, including 102 in vivo and 52 metabolites in vitro (51 in rat gut microbiota and 24 in rat liver microsomes). The main metabolic pathways include oxidation, reduction, hydrolysis, methylation, glucuronidation, sulfonation, and acetylation reactions. Furthermore, KEGG enrichment analysis revealed that the characteristic metabolites of intestinal microbiota may be related to the ErbB, FoxO, mTOR, and MAPK signaling pathways, exhibiting anti-inflammatory and anti-tumor effects. In summary, the chemical components and metabolites of Senecio scandens were comprehensively identified using a rapid and accurate method, providing a scientific basis for the in-depth study of the material basis and its clinical application of Senecio scandens.

Dietary Bacillus subtilis benefits meat quality by regulating the muscle fiber type and antioxidant capacity of broilers

The effects of dietary Bacillus subtilis (BS) on the meat quality of broilers were evaluated, with an emphasis on the regulation of muscle fiber types and antioxidant capabilities. One hundred and forty-four Arbor Acres male broilers were divided into 3 treatment groups (0, 300 mg/kg and 500 mg/kg dietary BS) and raised for 35 d. The results suggested that BS improved meat quality by improving the muscular pH, meat color, water holding capacity and shear force. Immunofluorescence staining revealed a positive impact of BS on the muscle fiber transformation in thigh muscles, and the gene/protein expression data from specific muscle fiber types confirmed this finding. BS activated AMP-activated protein kinase (AMPK), silent information regulator 1 and peroxisome proliferator-activated receptor gamma coactivator 1alpha. The postmortem analysis revealed that BS increased the activity of glutathione peroxidase and total antioxidant capacity while decreasing the malondialdehyde content. Additionally, BS increased the gene and protein expression of nuclear factor-like 2 (Nrf2) and activated the Nrf2 signaling pathway, including its downstream factors, such as heme oxygenase-1, catalase, superoxide dismutase and glutathione peroxidase. In conclusion, dietary BS improved meat quality by modifying muscle fiber types and enhancing the antioxidant capacity in broilers.

Ferulic acid restores mitochondrial dynamics and autophagy via AMPK signaling pathway in a palmitate-induced hepatocyte model of metabolic syndrome

Mitochondrial dysfunction, characterized by elevated oxidative stress, impaired energy balance, and dysregulated mitochondrial dynamics, is a hallmark of metabolic syndrome (MetS) and its comorbidities. Ferulic acid (FA), a principal phenolic compound found in whole grains, has demonstrated potential in ameliorating oxidative stress and preserving energy homeostasis. However, the influence of FA on mitochondrial health within the context of MetS remains unexplored. Moreover, the impact of FA on autophagy, which is essential for maintaining energy homeostasis and mitochondrial integrity, is not fully understood. Here, we aimed to study the mechanisms of action of FA in regulating mitochondrial health and autophagy using palmitate-treated HepG2 hepatocytes as a MetS cell model. We found that FA improved mitochondrial health by restoring redox balance and optimizing mitochondrial dynamics, including biogenesis and the fusion/fission ratio. Additionally, FA was shown to recover autophagy and activate AMPK-related cell signaling. Our results provide new insights into the therapeutic potential of FA as a mitochondria-targeting agent for the prevention and treatment of MetS.

A novel chromone-based as a potential inhibitor of ULK1 that modulates autophagy and induces apoptosis in colon cancer

Aim: Chromones are promising for anticancer drug development.Methods & results: 12 chromone-based compounds were synthesized and tested against cancer cell lines. Compound 8 showed the highest cytotoxicity (LC50 3.2 μM) against colorectal cancer cells, surpassing 5-fluorouracil (LC50 4.2 μM). It suppressed colony formation, induced cell cycle arrest and triggered apoptotic cell death, confirmed by staining and apoptosis markers. Cell death was accompanied by enhanced reactive oxygen species formation and modulation of the autophagic machinery (autophagy marker light chain 3B (LC3B); adenosine monophosphate-activated protein kinase (AMPK); protein kinase B (PKB); UNC-51-like kinase (ULK)-1; and ULK2). Molecular docking and dynamic simulations revealed that compound 8 directly binds to ULK1.Conclusion: Compound 8 is a promising lead for autophagy-modulating anti-colon cancer drugs.

Knockdown of EIF2AK2-OAS1 axis reduces ATP production inducing AMPK phosphorylation to inhibit the malignant behavior of gastric cancer cells

Energy metabolism has always been a hot topic in cancer progression and targeted therapy, and exploring the role of genes in energy metabolic pathways in cancer cells has become key to address this issue. Eukaryotic translation initiation factor 2α kinase 2 (EIF2AK2) plays regulatory roles in cancer and disorders of energy metabolism. Indeed, the role of EIF2AK2 in energy metabolism has been underestimated. The aim of this study is to reveal the expression specificity of EIF2AK2 in gastric cancer (GC) progression and metastasis, and to demonstrate the role of EIF2AK2 in energy metabolism, cytoskeleton, proliferation, death and metastasis pathways in GC cells. Mechanistically, EIF2AK2 overexpression promoted cytoskeleton remodeling and ATP production, mediated cell proliferation and metastasis, upregulated OAS1 expression, decreases p-AMPK expression and inhibited apoptosis in GC cells. Conversely, knockdown of EIF2AK2 resulted in the opposite effect. However, overexpression of OAS1 mediated the upregulation of mitochondrial membrane potential and promoted ATP production and NAD+/NADH ratio, but knockdown of OAS1 inhibited the above effects. In addition, knockdown of OAS1 had no effect on EIF2AK2 expression, but inhibited AMPK and upregulated p-AMPK expression. In conclusion, our study identified EIF2AK2 and OAS1 as previously undescribed regulators of energy metabolism in GC cells. We hypothesized that EIF2AK2-OAS1 axis may regulate energy metabolism and inhibit cellular malignant behavior in cancer cells by affecting ATP production to induce AMPK phosphorylation, suggesting EIF2AK2 as a potential therapeutic target for cancer cell progression.

AMPK regulates immature boar Sertoli cell proliferation through affecting CDK4/Cyclin D3 pathway and mitochondrial function

Sertoli cell (SC) proliferation plays an important role in sperm production and quality; however, the regulatory mechanism of SC proliferation is not well understood. This study investigated the role of adenosine monophosphate-activated protein kinase (AMPK) in the regulation of immature boar SC activity. Cell counting kit-8, Seahorse XFe96, mitochondrial respiratory enzyme-related assay kits, and transmission electron microscopy were used to detect SC proliferative viability, oxygen consumption rate (OCR), mitochondrial respiratory enzyme activity, and the ultrastructure of primary cultured SCs in vitro from the testes of 21-day-old boars. A dual luciferase reporter assay was performed to determine the miRNA-mRNA target interaction. Western blotting was used to analyze cell proliferation-related protein expression of p38, p21, proliferating cell nuclear antigen (PCNA), Cyclin-dependent kinase 4 (CDK4), Cyclin D3, and phosphorylated retinoblastoma protein (Rb). Each experiment had a completely randomized design, with three replicates in each experiment. The results showed that the AMPK inhibitor (Compound C, 20 μM-24 h) increased cell proliferation viability, ATP production, and maximal respiration of SCs by 0.64-, 0.12-, and 0.08-fold (p < 0.05), respectively; increased the SC protein expression of PCNA, CDK4, Cyclin D3, and p-Rb by 0.13-, 0.09-, 0.88-, and 0.12-fold (p < 0.05), respectively; and decreased the SC protein expression of p38 and p21 by 0.36- and 0.27-fold (p < 0.05), respectively. The AMPK agonist AICAR (2 mM-6 h) significantly inhibited SC ultrastructure, OCR, mitochondrial respiratory enzyme activity, and cell proliferation-related protein levels. AMPK was validated to be a target gene of miR-1285 based on the result in which the miR-1285 mimic inhibited the luciferase activity of wild-type AMPK by 0.54-fold (p < 0.001). MiR-1285 mimic promoted the OCR of SCs, with 0.45-, 0.15-, 0.21-, and 0.30-fold (p < 0.01) increases in ATP production, basal and maximal respiration, and spare capacity, respectively. MiR-1285 mimic increased the mitochondrial respiratory enzyme activity of SCs, with 0.63-, 0.70-, and 0.97-fold (p < 0.01) increases in NADH-Q oxidoreductase, cytochrome c oxidase, and ATP synthase, respectively. Moreover, the miR-1285 mimic increased the protein expression of PCNA, CDK4, Cyclin D3, and p-Rb by 0.24-, 0.30-, 0.22-, and 0.13-fold (p < 0.05), respectively, and reduced the protein expression of p38 and p21 by 0.58- and 0.66-fold (p < 0.001). MiR-1285 inhibitor showed opposite effects on the above indicators and induced numerous autophagosomes and large lipid droplets in SCs. A high dose of estradiol (10 μM-6 h, showed a promotion of AMPK activation in a previous study) significantly inhibited SC ultrastructure, mitochondrial function, and proliferation-related pathways, while these adverse effects were weakened by Compound C treatment or miR-1285 mimic transfection. Our findings suggest that the activation and inhibition of AMPK induced by specific drugs or synthesized targeted miRNA fragments could regulate immature boar SC proliferative activity by influencing the CDK4/Cyclin D3 pathway and mitochondrial function; this helps to provide a basis for the prevention and treatment of male sterility in clinical practice.

Resistance training boosts lactate transporters and synaptic proteins in insulin-resistance mice

Background

This investigation delineates the influence of resistance training on the expression of synaptic plasticity-related proteins in the hippocampi of insulin-resistant mice and explores the underlying molecular mechanisms.

Methods

Six-week-old male C57BL/6 J mice were stratified into a control group and a high-fat diet group to induce insulin resistance over a 12-week period. Subsequently, the mice were further divided into sedentary and resistance training cohorts, with the latter engaging in a 12-week ladder-climbing regimen. Post-intervention, blood, and hippocampal specimens were harvested for analytical evaluation.

Results

In the insulin-resistant mice, elevated blood lactate levels were observed alongside diminished expression of synaptic plasticity-related proteins, monocarboxylate transporters (MCTs), and reduced phosphorylation of protein kinase B (Akt) and mechanistic target of rapamycin (mTOR). In contrast, the expression of eukaryotic translation initiation factor 4 E-binding protein 2 was significantly augmented. Resistance training mitigated insulin resistance, decreased blood lactate levels, and enhanced the expression and phosphorylation of mTOR, regulatory-associated protein of mTOR, MCTs, and synaptic plasticity-related proteins.

Conclusions

Resistance training mitigates insulin resistance and improves hippocampal synaptic plasticity by normalizing blood lactate levels and enhancing mTOR, MCTs, and synaptic plasticity-related proteins. It may also activate mTORC1 via the PI3K/Akt pathway, promote lactate utilization, and enhance synaptic plasticity proteins, potentially alleviating peripheral insulin resistance. Further research is needed to confirm these mechanisms.

Bipyridine Derivatives as NOP2/Sun RNA Methyltransferase 3 Inhibitors for the Treatment of Colorectal Cancer

Based on the structure of caerulomycin A, 90 novel bipyridine derivatives were designed and synthesized. Among these, compound B19 exerted strong antitumor effects in vivo and in vitro. Importantly, NOP2/Sun RNA methyltransferase 3 (NSUN3) protein was identified as the target specific binding to B19, which inhibits oxidative phosphorylation of mitochondrial energy metabolism and enhances glycolytic activity by binding to NSUN3. Knockdown of NSUN3 inhibited both proliferation and migration of colorectal cancer (CRC) cells by activating AMPK-related signaling and inhibiting downstream STAT3 signaling to exert antiproliferative and pro-apoptotic effects. Our findings support the use of NSUN3 inhibitors as promising therapeutic strategies against CRC.

Systematical Investigation on Anti-Fatigue Function and Underlying Mechanism of High Fischer Ratio Oligopeptides from Antarctic Krill on Exercise-Induced Fatigue in Mice

High Fischer ratio oligopeptides (HFOs) have a variety of biological activities, but their mechanisms of action for anti-fatigue are less systematically studied at present. This study aimed to systematically evaluate the anti-fatigue efficacy of HFOs from Antarctic krill (HFOs-AK) and explore its mechanism of action through establishing the fatigue model of endurance swimming in mice. Therefore, according to the comparison with the endurance swimming model group, HFOs-AK were able to dose-dependently prolong the endurance swimming time, reduce the levels of the metabolites (lactic acid, blood urea nitrogen, and blood ammonia), increase the content of blood glucose, muscle glycogen, and liver glycogen, reduce lactate dehydrogenase and creatine kinase extravasation, and protect muscle tissue from damage in the endurance swimming mice. HFOs-AK were shown to enhance Na+-K+-ATPase and Ca2+-Mg2+-ATPase activities and increase ATP content in muscle tissue. Meanwhile, HFOs-AK also showed significantly antioxidant ability by increasing the activities of superoxide dismutase and glutathione peroxidase in the liver and decreasing the level of malondialdehyde. Further studies showed that HFOs-AK could regulate the body's energy metabolism and thus exert its anti-fatigue effects by activating the AMPK signaling pathway and up-regulating the expression of p-AMPK and PGC-α proteins. Therefore, HFOs-AK can be used as an auxiliary functional dietary molecules to exert its good anti-fatigue activity and be applied to anti-fatigue functional foods.

Ferroptosis: Latest evidence and perspectives on plant-derived natural active compounds mitigating doxorubicin-induced cardiotoxicity

Doxorubicin (DOX) is a chemotherapy drug widely used in clinical settings, acting as a first-line treatment for various malignant tumors. However, its use is greatly limited by the cardiotoxicity it induces, including doxorubicin-induced cardiomyopathy (DIC). The mechanisms behind DIC are not fully understood, but its potential biological mechanisms are thought to include oxidative stress, inflammation, energy metabolism disorders, mitochondrial damage, autophagy, apoptosis, and ferroptosis. Recent studies have shown that cardiac injury induced by DOX is closely related to ferroptosis. Due to their high efficacy, availability, and low side effects, natural medicine treatments hold strong clinical potential. Currently, natural medicines have been shown to mitigate DOX-induced ferroptosis and ease DIC through various functions such as antioxidation, iron ion homeostasis correction, lipid metabolism regulation, and mitochondrial function improvement. Therefore, this review summarizes the mechanisms of ferroptosis in DIC and the regulation by natural plant products, with the expectation of providing a reference for future research and development of inhibitors targeting ferroptosis in DIC. This review explores the mechanisms of ferroptosis in doxorubicin-induced cardiomyopathy (DIC) and summarizes how natural plant products can alleviate DIC by inhibiting ferroptosis through reducing oxidative stress, correcting iron ion homeostasis, regulating lipid metabolism, and improving mitochondrial function.

Quinoa Polyphenol Extract Alleviates Non-Alcoholic Fatty Liver Disease via Inhibiting Lipid Accumulation, Inflammation and Oxidative Stress

Recently, the incidence of NAFLD has exploded globally, but there are currently no officially approved medications for treating the condition. The regulation of NAFLD through plant-derived active substances has become a new area of interest. Quinoa (Chenopodium quinoa Willd.) has been discovered to contain a large quantity of bioactive compounds. In this study, we established a free fatty acid (FFA)-induced steatosis model and explored the effects of quinoa polyphenol extract (QPE) on the major hallmarks of NAFLD. The results indicated that QPE significantly reduced intracellular triglyceride (TG) and total cholesterol (TC) levels. Additionally, QPE remarkably elevated the levels of superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) and lowered levels of malondialdehyde (MDA). Further examination revealed that QPE attenuated intracellular inflammation, which was verified by the reduced levels of pro-inflammatory cytokines. Mechanistically, QPE inhibited fatty acid biosynthesis mainly by targeting de novo lipogenesis (DNL) via the AMPK/SREBP-1c signaling pathway. Moreover, network pharmacology was used to analyze key targets for NAFLD mitigation by ferulic acid (FA), a major component of QPE. Taken together, this study suggests that QPE could ameliorate NAFLD by modulating hepatic lipid metabolism and alleviating oxidative stress and inflammation.

Role of AMPK-regulated autophagy in retinal pigment epithelial cell homeostasis: A review

The retinal pigment epithelium (RPE) is a regularly arranged monolayer of cells in the outermost layer of the retina. It is crucial for transporting nutrients and metabolic substances in the retina and maintaining the retinal barrier. RPE dysfunction causes diseases related to vision loss. Thus, understanding the mechanisms involved in normal RPE function is vital. Adenosine monophosphate-activated protein kinase (AMPK) is an RPE energy sensor regulating various signaling and metabolic pathways to maintain cellular energetic homeostasis. AMPK activation is involved in multiple signaling pathways regulated by autophagy in the RPE, thereby protecting the cells from oxidative stress and slowing RPE degeneration. In this review, we attempt to broaden the understanding of the pathogenesis of RPE dysfunction by focusing on the role and mechanism of AMPK regulation of autophagy in the RPE. The correlation between RPE cellular homeostasis and role of AMPK was determined by analyzing the structure and mechanism of AMPK and its signaling pathway in autophagy. The protective effect of AMPK-regulated autophagy on the RPE for gaining insights into the regulatory pathways of RPE dysfunction has been discussed.

Untargeted Metabolomic Analysis Reveals Plasma Differences between Mares with Endometritis and Healthy Ones

The aim of this study was to explore alterations in plasma metabolites among mares afflicted with endometritis. Mares were divided into two groups, namely, the equine endometritis group (n = 8) and the healthy control group (n = 8), which included four pregnant and four non-pregnant mares, using a combination of clinical assessment and laboratory confirmation. Plasma samples from both groups of mares were analyzed through untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) metabolomics. A total of 28 differentially abundant metabolites were identified by screening and identifying differentially abundant metabolites and analyzing the pathway enrichment of differentially. Ten metabolites were identified as potential biomarkers for the diagnosis of endometritis in mares. Among them, seven exhibited a decrease in the endometritis groups, including hexadecanedioic acid, oleoyl ethanolamide (OEA), [fahydroxy(18:0)]12_13-dihydroxy-9z-octa (12,13-diHOME), deoxycholic acid 3-glucuronide (DCA-3G), 2-oxindole, and (+/-)9-HPODE, and 13(S)-HOTRE. On the other hand, three metabolites, adenosine 5'-monophosphate (AMP), 5-hydroxy-dl-tryptophan (5-HTP), and l-formylkynurenine, demonstrated an increase. These substances primarily participate in the metabolism of tryptophan and linolenic acid, as well as fat and energy. In conclusion, metabolomics revealed differentially abundant metabolite changes in patients with mare endometritis. These specific metabolites can be used as potential biomarkers for the non-invasive diagnosis of mare endometritis.

Frontiers in sarcopenia: Advancements in diagnostics, molecular mechanisms, and therapeutic strategies

The onset of sarcopenia is intimately linked with aging, posing significant implications not only for individual patient quality of life but also for the broader societal healthcare framework. Early and accurate identification of sarcopenia and a comprehensive understanding of its mechanistic underpinnings and therapeutic targets paramount to addressing this condition effectively. This review endeavors to present a cohesive overview of recent advancements in sarcopenia research and diagnosis. We initially delve into the contemporary diagnostic criteria, specifically referencing the European Working Group on Sarcopenia in Older People (EWGSOP) 2 and Asian Working Group on Sarcopenia (AWGS) 2019 benchmarks. Additionally, we elucidate comprehensive assessment techniques for muscle strength, quantity, and physical performance, highlighting tools such as grip strength, chair stand test, dual-energy X-ray Absorptiometry (DEXA), bioelectrical impedance analysis (BIA), gait speed, and short physical performance battery (SPPB), while also discussing their inherent advantages and limitations. Such diagnostic advancements pave the way for early identification and unequivocal diagnosis of sarcopenia. Proceeding further, we provide a deep-dive into sarcopenia's pathogenesis, offering a thorough examination of associated signaling pathways like the Myostatin, AMP-activated protein kinase (AMPK), insulin/IGF-1 Signaling (IIS), and the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathways. Each pathway's role in sarcopenia mediation is detailed, underscoring potential therapeutic target avenues. From a mechanistic perspective, the review also underscores the pivotal role of mitochondrial dysfunction in sarcopenia, emphasizing elements such as mitochondrial oxidative overload, mitochondrial biogenesis, and mitophagy, and highlighting their therapeutic significance. At last, we capture recent strides made in sarcopenia treatment, ranging from nutritional and exercise interventions to potential pharmacological and supplementation strategies. In sum, this review meticulously synthesizes the latest scientific developments in sarcopenia, aiming to enhance diagnostic precision in clinical practice and provide comprehensive insights into refined mechanistic targets and innovative therapeutic interventions, ultimately contributing to optimized patient care and advancements in the field.

Alisol B regulates AMPK/mTOR/SREBPs via directly targeting VDAC1 to alleviate hyperlipidemia

BACKGROUND

The occurrence of hyperlipidemia is significantly influenced by lipid synthesis, which is regulated by sterol regulatory element binding proteins (SREBPs), thus the development of drugs that inhibit lipid synthesis has become a popular treatment strategy for hyperlipidemia. Alisol B (ALB), a triterpenoid compound extracted from Alisma, has been reported to ameliorate no-nalcoholic steatohepatitis (NASH) and slow obesity. However, the effect of ALB on hyperlipidemia and mechanism are unclear.

PURPOSE

To examine the therapeutic impact of ALB on hyperlipidemia whether it inhibits SREBPs to reduce lipid synthesis.

STUDY DESIGN

HepG2, HL7702 cells, and C57BL/6J mice were used to explore the effect of ALB on hyperlipidemia and the molecular mechanism in vivo and in vitro.

METHODS

Hyperlipidemia models were established using western diet (WD)-fed mice in vivo and oleic acid (OA)-induced hepatocytes in vitro. Western blot, real-time PCR and other biological methods verified that ALB regulated AMPK/mTOR/SREBPs to inhibit lipid synthesis. Cellular thermal shift assay (CETSA), molecular dynamics (MD), and ultrafiltration-LC/MS analysis were used to evaluate the binding of ALB to voltage-dependent anion channel protein-1 (VDAC1).

RESULTS

ALB decreased TC, TG, LDL-c, and increased HDL-c in blood, thereby ameliorating liver damage. Gene set enrichment analysis (GSEA) indicated that ALB inhibited the biosynthesis of cholesterol and fatty acids. Consistently, ALB inhibited the protein expression of n-SREBPs and downstream genes. Mechanistically, the impact of ALB on SREBPs was dependent on the regulation of AMPK/mTOR, thereby impeding the transportation of SREBPs from endoplasmic reticulum (ER) to golgi apparatus (GA). Further investigations indicated that the activation of AMPK by ALB was independent on classical upstream CAMKK2 and LKB1. Instead, ALB resulted in a decrease in ATP levels and an increase in the ratios of ADP/ATP and AMP/ATP. CETSA, MD, and ultrafiltration-LC/MS analysis indicated that ALB interacted with VDAC1. Molecular docking revealed that ALB directly bound to VDAC1 by forming hydrogen bonds at the amino acid sites S196 and H184 in the ATP-binding region. Importantly, the thermal stabilization of ALB on VDAC1 was compromised when VDAC1 was mutated at S196 and H184, suggesting that these amino acids played a crucial role in the interaction.

CONCLUSION

Our findings reveal that VDAC1 serves as the target of ALB, leading to the inhibition of lipid synthesis, presents potential target and candidate drugs for hyperlipidemia.

Inhibitory effects of black phosphorus nanosheets on tumor cell proliferation through downregulation of ADIPOQ and downstream signaling pathways

Exposure to environmental pollutants, including nanomaterials, has a significant impact on tumor progression. The increased demand for black phosphorus nanosheets (BPNSs), driven by their exceptional properties, raises concerns about potential environmental contamination. Assessing their toxicity on tumor growth is essential. Herein, we employed a range of biological techniques, including cytotoxicity measurement, bioinformatics tools, proteomics, target gene overexpression, Western blot analysis, and apoptosis detection, to investigate the toxicity of BPNSs across A549, HepG-2, MCF-7, and Caco-2 cell lines. Our results demonstrated that BPNSs downregulated the expression of ADIPOQ and its associated downstream pathways, such as AMP-activated protein kinase (AMPK), nuclear factor erythroid 2-related factor 2 (Nrf2), and other unidentified pathways. These downregulated pathways ultimately led to mitochondria-dependent apoptosis. Notably, the specific downstream pathways involved varied depending on the type of tumors. These insightful findings not only confirm the consistent inhibitory effects of BPNSs across different tumor cells, but also elucidate the cytotoxicity mechanisms of BPNSs in different tumors, providing valuable information for their safe application and health risk assessment.

Distinct spectral signatures unfold ECM stiffness-triggered biochemical changes in breast cancer cells

Cancer progression often accompanies the stiffening of extracellular matrix (ECM) in and around the tumor, owing to extra deposition and cross-linking of collagen. Stiff ECM has been linked with poor prognosis and is known to fuel invasion and metastasis, notably in breast cancer. However, the underlying biochemical or metabolic changes and the cognate molecular signatures remain elusive. Here, we explored Raman spectroscopy to unveil the spectral fingerprints of breast cancer cells in response to extracellular mechanical cues. Using stiffness-tuneable hydrogels, we showed that cells grown on stiff ECM displayed morphological changes with high proliferation. We further demonstrated that Raman Spectroscopy, a label-free and non-invasive technique, could provide comprehensive information about the biochemical environment of breast cancer cells in response to varying ECM stiffness. Raman spectroscopic analysis classified the cells into distinct clusters based on principal component-based linear discriminant analysis (PC-LDA). Multivariate curve resolution-alternating least squares (MCR-ALS) analysis indicated that cells cultured on stiff ECM exhibited elevated nucleic acid content and lesser lipids. Interestingly, increased intensity of Raman bands corresponding to cytochrome-c was also observed in stiff ECM conditions, suggesting mitochondrial modulation. The key findings harboured by spectral profiles were also corroborated by transmission electron microscopy, confirming altered metabolic status as reflected by increased mitochondria number and decreased lipid droplets in response to ECM stiffening. Collectively, these findings not only give the spectral signatures for mechanoresponse but also provide the landscape of biochemical changes in response to ECM stiffening.

Interplay between lipid dysregulation and ferroptosis in chondrocytes and the targeted therapy effect of metformin on osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is a devastating whole-joint disease affecting a large population worldwide; the role of lipid dysregulation in OA and mechanisms underlying targeted therapy effect of lipid-lowering metformin on OA remains poorly defined.

OBJECTIVES

To investigate the effects of lipid dysregulation on OA progression and to explore lipid dysregulation-targeting OA treatment of metformin.

METHODS

RNA-Seq data, biochemical, and histochemical assays in human and murine OA cartilage as well as primary chondrocytes were utilized to determine lipid dysregulation. Effects of metformin, a potent lipid-lowering medication, on ACSL4 expression and chondrocyte metabolism were determined. Further molecular experiments, including RT-qPCR, western blotting, flow cytometry, and immunofluorescence staining, were performed to investigate underlying mechanisms. Mice with intra-articular injection of metformin were utilized to determine the effects on ACLT-induced OA progression.

RESULTS

ACSL4 and 4-HNE expressions were elevated in human and ACLT-induced mouse OA cartilage and IL-1β-treated chondrocytes (P < 0.05). Ferrostatin-1 largely rescued IL-1β-induced MDA, lipid peroxidation, and ferroptotic mitochondrial morphology (P < 0.05). Metformin decreased the levels of OA-related genes (P < 0.05) and increased the levels of p-AMPK and p-ACC in IL-1β-treated chondrocytes. Intra-articular injection of metformin alleviated ACLT-induced OA lesions in mice, and reverted the percentage of chondrocytes positive for MMP13, Col2a1, ACSL4 and 4-HNE in ACLT mice (P < 0.05). Ferroptotic chondrocytes promoted the recruitment and chemotaxis of RAW264.7 cells via CCL2, which was blocked by metformin in vitro (P < 0.05).

CONCLUSION

We establish a critical role of polyunsaturated fatty acids metabolic process in OA cartilage degradation and define metformin as a potential OA treatment. Metformin reshapes lipid availability and ameliorates chondrocyte ferroptosis sensitivity via the AMPK/ACC pathway. In the future, gene-edited animals and extensive omics technologies will be utilized to reveal detailed lipids' involvement in cartilage lesions.

Evolution of innate immunity: lessons from mammalian models shaping our current view of insect immunity

The innate immune system, a cornerstone for organismal resilience against environmental and microbial insults, is highly conserved across the evolutionary spectrum, underpinning its pivotal role in maintaining homeostasis and ensuring survival. This review explores the evolutionary parallels between mammalian and insect innate immune systems, illuminating how investigations into these disparate immune landscapes have been reciprocally enlightening. We further delve into how advancements in mammalian immunology have enriched our understanding of insect immune responses, highlighting the intertwined evolutionary narratives and the shared molecular lexicon of immunity across these organisms. Therefore, this review posits a holistic understanding of innate immune mechanisms, including immunometabolism, autophagy and cell death. The examination of how emerging insights into mammalian and vertebrate immunity inform our understanding of insect immune responses and their implications for vector-borne disease transmission showcases the imperative for a nuanced comprehension of innate immunity's evolutionary tale. This understanding is quintessential for harnessing innate immune mechanisms' potential in devising innovative disease mitigation strategies and promoting organismal health across the animal kingdom.

Phytochemicals targeting Alzheimer's disease via the AMP-activated protein kinase pathway, effects, and mechanisms of action

Alzheimer's disease (AD), characterized by cognitive dysfunction and other behavioral abnormalities, is a progressive neurodegenerative disease that occurs due to aging. Currently, effective drugs to mitigate or treat AD remain unavailable. AD is associated with several abnormalities in neuronal energy metabolism, such as decreased glucose uptake, mitochondrial dysfunction, and defects in cholesterol metabolism. Amp-activated protein kinase (AMPK) is an important serine/threonine protein kinase that regulates the energy status of cells. AMPK is widely present in eukaryotic cells and can sense and regulate energy metabolism to maintain energy supply and demand balance, making it a promising target for energy metabolism-based AD therapy. Therefore, this review aimed to discuss the molecular mechanism of AMPK in the pathogenesis of AD to provide a theoretical basis for the development of new anti-AD drugs. To review the mechanisms of phytochemicals in the treatment of AD via AMPK pathway regulation, we searched PubMed, Google Scholar, Web of Science, and Embase databases using specific keywords related to AD and phytochemicals in September 2023. Phytochemicals can activate AMPK or regulate the AMPK pathway to exert therapeutic effects in AD. The anti-AD mechanisms of these phytochemicals include inhibiting Aβ aggregation, preventing Tau hyperphosphorylation, inhibiting inflammatory response and glial activation, promoting autophagy, and suppressing anti-oxidative stress. Additionally, several AMPK-related pathways are involved in the anti-AD mechanism, including the AMPK/CaMKKβ/mTOR, AMPK/SIRT1/PGC-1α, AMPK/NF-κB/NLRP3, AMPK/mTOR, and PERK/eIF2α pathways. Notably, urolithin A, artemisinin, justicidin A, berberine, stigmasterol, arctigenin, and rutaecarpine are promising AMPK agonists with anti-AD effects. Several phytochemicals are effective AMPK agonists and may have potential applications in AD treatment. Overall, phytochemical-based drugs may overcome the barriers to the effective treatment of neurodegenerative diseases.

Methyl Cinnamate (MC) Alleviates Free Fatty Acids (FFAs) Induced Lipid Accumulation Through the AMPK Pathway in HepG2 Cells

Background

AMP-activated protein kinase (AMPK) plays a critical role in energy metabolism. Its activation leads to the phosphorylation of downstream proteins such as acetyl-CoA carboxylase (ACC) and sterol regulatory element-binding protein-1 (SREBP1), subsequently inhibiting de novo fatty acid synthesis, thereby reducing intracellular triglyceride accumulation. MC is a compound found in extracts from Zanthoxylum armatum DC plants. Research has shown that MC can inhibit the differentiation of 3T3-L1 adipocytes through the CAMKK2-AMPK pathway. However, the biological effect of MC in HepG2 cells remains unknown.

Methods

In this study, we utilized HepG2 cells to establish a model of MAFLD through FFAs stimulation. We investigated the biological effects of MC on HepG2 cells and studied its impact on lipid metabolism. Small interfering RNA was employed to explore the mechanism by which MC activates AMPK. Finally, molecular docking was conducted, establishing a model of the interaction between AMPK and MC.

Results

We observed that MC can alleviate triglyceride accumulation in HepG2 cells. We observed the elevated p-AMPK/AMPK, P-ACC/ ACC, and elevated CPT1a after treatment of MC in HepG2 cells. The interference of CAMKK2 mRNA did not impact the ability of MC to phosphorylate AMPK. Compound C attenuates the ability of MC to increase p-AMPK. Molecular docking results led us to hypothesize that MC directly interacts with AMPK, resulting in AMPK phosphorylation and improved lipid accumulation in HepG2 cells.

Exploring the Anti-Diabetic Potential of Quercetagitrin through Dual Inhibition of PTPN6 and PTPN9

Protein tyrosine phosphatases (PTPs) are pivotal contributors to the development of type 2 diabetes (T2DM). Hence, directing interventions towards PTPs emerges as a valuable therapeutic approach for managing type 2 diabetes. In particular, PTPN6 and PTPN9 are targets for anti-diabetic effects. Through high-throughput drug screening, quercetagitrin (QG) was recognized as a dual-target inhibitor of PTPN6 and PTPN9. We observed that QG suppressed the catalytic activity of PTPN6 (IC50 = 1 μM) and PTPN9 (IC50 = 1.7 μM) in vitro and enhanced glucose uptake by mature C2C12 myoblasts. Additionally, QG increased the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and insulin-dependent phosphorylation of Akt in mature C2C12 myoblasts. It further promoted the phosphorylation of Akt in the presence of palmitic acid, suggesting the attenuation of insulin resistance. In summary, our results indicate QG's role as a potent inhibitor targeting both PTPN6 and PTPN9, showcasing its potential as a promising treatment avenue for T2DM.

A Mixture of Formic Acid, Benzoic Acid, and Essential Oils Enhanced Growth Performance via Modulating Nutrient Uptake, Mitochondrion Metabolism, and Immunomodulation in Weaned Piglets

This study aimed to evaluate the effects of a complex comprising formic acid, benzoic acid, and essential oils (AO3) on the growth performance of weaned piglets and explore the underlying mechanism. Dietary AO3 supplementation significantly enhanced the average daily gain (ADG) and average daily feed intake (ADFI), while decreasing the feed conversion rate (FCR) and diarrhea rate (p < 0.05). Additionally, AO3 addition altered the fecal microflora composition with increased abundance of f_Prevotellaceae. LPS challenges were further conducted to investigate the detailed mechanism underlying the benefits of AO3 supplementation. The piglets fed with AO3 exhibited a significant increase in villus height and decrease in crypt depth within the jejunum, along with upregulation of ZO-1, occludin, and claudin-1 (p < 0.05) compared with those piglets subjected to LPS. Furthermore, AO3 supplementation significantly ameliorated redox disturbances (T-AOC, SOD, and GSH) and inflammation (TNF-α, IL-1β, IL-6, and IL-12) in both the serum and jejunum of piglets induced by LPS, accompanied by suppressed activation of the MAPK signaling pathway (ERK, JNK, P38) and NF-κB. The LPS challenge downregulated the activation of the AMPK signaling pathway, mRNA levels of electron transport chain complexes, and key enzymes involved in ATP synthesis, which were significantly restored by the AO3 supplementation. Additionally, AO3 supplementation restored the reduced transport of amino acids, glucose, and fatty acids induced by LPS back to the levels observed in the control group. In conclusion, dietary AO3 supplementation positively affected growth performance and gut microbiota composition, also enhancing intestinal barrier integrity, nutrient uptake, and energy metabolism, as well as alleviating oxidative stress and inflammation under LPS stimulation.

Effects of exercise, metformin, and combination treatments on type 2 diabetic mellitus-induced muscle atrophy in db/db mice: Crosstalk between autophagy and the proteasome

Both exercise and metformin are common effective clinical treatments of type 2 diabetic mellitus. This study investigated the functional role of exercise, metformin, and combination treatment on type 2 diabetic mellitus-induced muscle atrophy. In this experiment, a total of 10 BKS mice were set as the control group. A total of 40 BKS-db/db mice were randomly divided into the control group (db/db); the exercise intervention group (db/db + Ex), which ran on a treadmill at 7-12 m/min, 30-40 min/day, 5 days/week; the metformin administration group (db/db + Met), which was administered 300 mg/kg of metformin solution by gavage daily; and the exercise combined with metformin administration group (db/db + Ex + Met). After 8 weeks of intervention, their tibialis anterior muscles were removed. The levels of insulin signaling pathway proteins, ubiquitin proteasome, and autophagic lysosome-associated proteins were detected using western blot, the expression of MuRF1 and Atrogin-1 was detected using immunohistochemical staining, and the degradation of autophagosomes was detected using double-labeled immunofluorescence. The db/db mice exhibited reduced insulin sensitivity and inhibition of the autophagic-lysosome system, the ubiquitin-proteasome system was activated, and protein degradation was exacerbated, leading to skeletal muscle atrophy. Exercise and metformin and their combined interventions can increase insulin sensitivity, whereas exercise alone showed more effective in inhibiting the ubiquitin-proteasome system, improving autophagy levels, and alleviating skeletal muscle atrophy. Compared with metformin, exercise demonstrated superior improvement of muscle atrophy by promoting the synthesis and degradation of autophagy through the AMPK/ULK1 pathway. However, the combination treatment exhibits no synergistic effect on muscle atrophy.

Increased Expression of Proinflammatory Genes in Peripheral Blood Cells Is Associated with Cardiac Cachexia in Patients with Heart Failure with Reduced Ejection Fraction

Background: Cardiac cachexia (CC) in chronic heart failure with reduced ejection fraction (HFrEF) is characterized by catabolism and inflammation predicting poor prognosis. Levels of responsible transcription factors like signal transducer and activator of transcription (STAT)1, STAT3, suppressor of cytokine signaling (SOCS)1 and SOCS3 in peripheral blood cells (PBC) are underinvestigated in CC. Expression of mediators was related to patients' functional status, body composition (BC) and metabolic gene expression in skeletal muscle (SM). Methods: Gene expression was quantified by qRT-PCR in three cohorts: non-cachectic patients (ncCHF, n = 19, LVEF 31 ± 7%, BMI 30.2 ± 5.0 kg/m2), cachectic patients (cCHF; n = 18, LVEF 27 ± 7%, BMI 24.3 ± 2.5 kg/m2) and controls (n = 17, LVEF 70 ± 7%, BMI 27.6 ± 4.6 kg/m2). BC was assessed by dual-energy X-ray absorptiometry. Blood inflammatory markers were measured. We quantified solute carrier family 2 member 4 (SLC2A4) and protein degradation by expressions of proteasome 20S subunit beta 2 and calpain-1 catalytic subunit in SM biopsies. Results: TNF and IL-10 expression was higher in cCHF than in ncCHF and controls (all p < 0.004). cCHF had a lower fat mass index (FMI) and lower fat-free mass index (FFMI) compared to ncCHF and controls (p < 0.05). STAT1 and STAT3 expression was higher in cCHF vs. ncCHF or controls (1.1 [1.6] vs. 0.8 [0.9] vs. 0.9 [1.1] RU and 4.6 [5.5] vs. 2.5 [4.8] vs. 3.0 [4.2] RU, all ANOVA-p < 0.05). The same applied for SOCS1 and SOCS3 expression (1.1 [1.5] vs. 0.4 [0.4] vs. 0.4 [0.5] and 0.9 [3.3] vs. 0.4 [1.1] vs. 0.8 [0.9] RU, all ANOVA-p < 0.04). In cCHF, higher TNF and STAT1 expression was associated with lower FMI (r = 0.5, p = 0.053 and p < 0.05) but not with lower FFMI (p > 0.4). In ncCHF, neither cytokine nor STAT/SOCS expression was associated with BC (all p > 0.3). SLC2A4 was upregulated in SM of cCHF vs. ncCHF (p < 0.03). Conclusions: Increased STAT1, STAT3, SOCS1 and SOCS3 expression suggests their involvement in CC. In cCHF, higher TNF and STAT-1 expression in PBC were associated with lower FMI. Increased SLC2A4 in cachectic SM biopsies indicates altered glucose metabolism.

Nuclear DNA damage-triggered ATM-dependent AMPK activation regulates the mitochondrial radiation response

PURPOSE

AMP-activated protein kinase (AMPK) acts as a cellular energy sensor and is essential for controlling mitochondrial homeostasis. Here, we investigated the regulatory mechanisms involved in AMPK activation to elucidate how networks of intracellular signaling pathways respond to stress conditions.

MATERIALS AND METHODS

Inhibitors of ATM, DNA-PK, and AKT were tested in normal TIG-3 and MRC-5 human fibroblasts to determine which upstream kinases are responsible for AMPK activation. SV40 transformed-human ATM-deficient fibroblasts (AT5BIVA) and their ATM-complemented cells (i.e., AT5BIVA/ATMwt) were also used. Protein expression associated with AMPK signaling was examined by immunostaining and/or Western blotting.

RESULTS

Radiation-induced nuclear DNA damage activates ATM-dependent AMPK signaling pathways that regulate mitochondrial quality control. In contrast, hypoxia and glucose starvation caused ATP depletion and activated AMPK via a pathway independent of ATM. DNA-PK and AKT are not involved in AMPK-mediated mitochondrial signaling pathways.

CONCLUSION

Activation of the AMPK signaling pathway differs depending on the stimulus. Radiation activates AMPK through two pathways: depletion of ATP-mediated LKB1 signaling and nuclear DNA damage-induced ATM signaling. Nuclear DNA damage signaling to mitochondria therefore plays a pivotal role in determining the cell fates of irradiated cells.

Integrated Functions of Cardiac Energetics, Mechanics, and Purine Nucleotide Metabolism

Purine nucleotides play central roles in energy metabolism in the heart. Most fundamentally, the free energy of hydrolysis of the adenine nucleotide adenosine triphosphate (ATP) provides the thermodynamic driving force for numerous cellular processes including the actin-myosin crossbridge cycle. Perturbations to ATP supply and/or demand in the myocardium lead to changes in the homeostatic balance between purine nucleotide synthesis, degradation, and salvage, potentially affecting myocardial energetics and, consequently, myocardial mechanics. Indeed, both acute myocardial ischemia and decompensatory remodeling of the myocardium in heart failure are associated with depletion of myocardial adenine nucleotides and with impaired myocardial mechanical function. Yet there remain gaps in the understanding of mechanistic links between adenine nucleotide degradation and contractile dysfunction in heart disease. The scope of this article is to: (i) review current knowledge of the pathways of purine nucleotide depletion and salvage in acute ischemia and in chronic heart disease; (ii) review hypothesized mechanisms linking myocardial mechanics and energetics with myocardial adenine nucleotide regulation; and (iii) highlight potential targets for treating myocardial metabolic and mechanical dysfunction associated with these pathways. It is hypothesized that an imbalance in the degradation, salvage, and synthesis of adenine nucleotides leads to a net loss of adenine nucleotides in both acute ischemia and under chronic high-demand conditions associated with the development of heart failure. This reduction in adenine nucleotide levels results in reduced myocardial ATP and increased myocardial inorganic phosphate. Both of these changes have the potential to directly impact tension development and mechanical work at the cellular level. © 2024 American Physiological Society. Compr Physiol 14:5345-5369, 2024.

Resveratrol Improves the Frozen-Thawed Ram Sperm Quality

Cryopreservation generates a substantial quantity of ROS in semen, leading to a decline in sperm quality and fertilization capacity. The objective of this study was to investigate the effects of resveratrol and its optimal concentration on ram sperm quality after cryopreservation. Ram semen was diluted with a freezing medium containing different concentrations of resveratrol (0, 25, 50, 75, and 100 μM). After thawing, various sperm parameters such as total motility, progressive motility, acrosome integrity, plasma membrane integrity, mitochondrial membrane potential, glutathione (GSH) content, glutathione synthase (GPx) activity, superoxide dismutase (SOD) activity, catalase (CAT) activity, lipid peroxidation (LPO) content, malondialdehyde (MDA) content, ROS level, SIRT1 level, DNA oxidative damage, and AMPK phosphorylation level were assessed. In addition, post-thaw sperm apoptosis was evaluated. Comparatively, the addition of resveratrol up to 75 μM significantly improved the sperm motility and sperm parameters of cryopreserved ram sperm. Specifically, 50 μM resveratrol demonstrated a notable enhancement in acrosome and plasma membrane integrity, antioxidant capacity, mitochondrial membrane potential, adenosine triphosphate (ATP) content, SIRT1 level, and AMPK phosphorylation levels compared to the control group (p < 0.05). It also significantly (p < 0.05) reduced the oxidative damage to sperm DNA. However, detrimental effects of resveratrol were observed at a concentration of 100 μM resveratrol. In conclusion, the addition of 50 μM resveratrol to the cryopreservation solution is optimal for enhancing the quality of cryopreserved ram sperm.

Anti-adipogenic action of a novel oxazole derivative through activation of AMPK pathway

Obesity is a chronic disorder with multifactorial etiology, including genetic, medical, dietary and other environmental factors. Both natural and synthetic heterocyclic compounds, especially oxazoles, represent an interesting group of compounds and have gained much attention due to their remarkable biological activities. Therefore, a library of 3,3-DMAH (3,3-dimethylallylhalfordinol) inspired N-alkylated oxazole bromide salts with varied substitutions were prepared and screened using the 3T3-L1 model of adipogenesis and HFD-induced obesity model in Syrian golden hamsters. Several compounds in the synthesized series displayed remarkable anti-adipogenic potential on the differentiation of 3T3-L1 preadipocytes. Compound 19e, displayed the most potent activity of all and selected for further studies. Compound 19e inhibited mitotic clonal expansion of 3T3-L1 cells and enhanced the mitochondrial oxygen consumption rate of the cells during early phase of differentiation via AMPK activation. 19e also improved the dyslipidaemia in high calorie diet fed Syrian Golden Hamsters. Therefore, compound 19e can serve as a potential lead against adipogenesis and dyslipidaemia models and could be further investigated to affirm its significance as a drug candidate.

Enhancing the anticancer potential of metformin: fabrication of efficient nanospanlastics, in vitro cytotoxic studies on HEP-2 cells and reactome enhanced pathway analysis

Metformin (MET), an oral antidiabetic drug, was reported to possess promising anticancer effects. We hypothesized that MET encapsulation in unique nanospanlastics would enhance its anticancer potential against HEP-2 cells. Our results showed the successful fabrication of Nano-MET spanlastics (d = 232.10 ± 0.20 nm; PDI = 0.25 ± 0.11; zeta potential = (-) 44.50 ± 0.96; drug content = 99.90 ± 0.11 and entrapment efficiency = 88.01 ± 2.50%). MTT assay revealed the enhanced Nano-MET cytotoxicity over MET with a calculated IC50 of 50 μg/mL and > 500 μg/mL, respectively. Annexin V/PI apoptosis assay showed that Nano-MET significantly decreased the percentage of live cells from 95.49 to 93.70 compared to MET and increased the percentage of cells arrested in the G0/G1 phase by 8.38%. Moreover, Nano-MET downregulated BCL-2 and upregulated BAX protein levels by 1.57 and 1.88 folds, respectively. RT-qPCR revealed that Nano-MET caused a significant 13.75, 4.15, and 2.23-fold increase in caspase-3, -8, and - 9 levels as well as a 100 and 43.47-fold decrease in cyclin D1 and mTOR levels, respectively. The proliferation marker Ki67 immunofluorescent staining revealed a 3-fold decrease in positive cells in Nano-MET compared to the control. Utilizing the combined Pathway-Enrichment Analysis (PEA) and Reactome analysis indicated high enrichment of certain pathways including nucleotides metabolism, Nudix-type hydrolase enzymes, carbon dioxide hydration, hemostasis, and the innate immune system. In summary, our results confirm MET cytotoxicity enhancement by its encapsulation in nanospanlastics. We also highlight, using PEA, that MET can modulate multiple pathways implicated in carcinogenesis.

Effects of Cinnamon (Cinnamomum zeylanicum) Extract on Adipocyte Differentiation in 3T3-L1 Cells and Lipid Accumulation in Mice Fed a High-Fat Diet

Flavonoids and phenolic acid are two of the rich polyphenols found in cinnamon (Cinnamomum zeylanicum). The effects of cinnamon extract on the inhibition of adipocyte differentiation in 3T3-L1 fibroblast cells and prohibitory lipid accumulation in male mice fed a high-fat diet were examined. Upon treating 3T3-L1 cells with cinnamon for 3 days, the cinnamon inhibited lipid accumulation and increased gene expression levels, such as those of adiponectin and leptin. In in vivo experiments, mice were randomized into four groups after a one-week acclimation period, as follows: normal diet, normal diet + 1% cinnamon extract, high-fat diet, and high-fat diet + 1% cinnamon extract. After 14 weeks of supplementation, we found that cinnamon extract increased the expression of lipolysis-related proteins, such as AMPK, p-ACC, and CPT-1, and reduced the expression of lipid-synthesis-related proteins, such as SREBP-1c and FAS, in liver tissue. Our results show that cinnamon extract may exhibit anti-obesity effects via the inhibition of lipid synthesis and adipogenesis and the induction of lipolysis in both 3T3-L1 fibroblast cells and mice fed a high-fat diet. Accordingly, cinnamon extract may have potential anti-obesity effects.

The role of AMPK in macrophage metabolism, function and polarisation

AMP-activated protein kinase (AMPK) is a ubiquitous sensor of energy and nutritional status in eukaryotic cells. It plays a key role in regulating cellular energy homeostasis and multiple aspects of cell metabolism. During macrophage polarisation, AMPK not only guides the metabolic programming of macrophages, but also counter-regulates the inflammatory function of macrophages and promotes their polarisation toward the anti-inflammatory phenotype. AMPK is located at the intersection of macrophage metabolism and inflammation. The metabolic characteristics of macrophages are closely related to immune-related diseases, infectious diseases, cancer progression and immunotherapy. This review discusses the structure of AMPK and its role in the metabolism, function and polarisation of macrophages. In addition, it summarises the important role of the AMPK pathway and AMPK activators in the development of macrophage-related diseases.

Catalpol ameliorates LPS-induced inflammatory response by activating AMPK/mTOR signaling pathway in rat intestinal epithelial cells

Intestinal inflammation is a common clinical intestinal disease. Catalpol, a natural iridoid compound, has been shown to have anti-inflammatory, anti-oxidant and anti-apoptotic functions, but the mechanism of its protection against intestinal inflammation is still unclear. This study investigated the protective effect and potential mechanism of catalpol on the lipopolysaccharide (LPS)-induced inflammatory response of intestinal epithelial cell-6 (IEC-6). The results showed that catalpol could inhibit LPS-induced inflammatory response by dose-dependently reducing the release of inflammatory factors, such as tumor necrosis (TNF)-α, interleukin (IL)-1β and IL-6, and inhibiting the nuclear factor kappa-B (NF-κB) signaling pathway. Catalpol ameliorated cellular oxidative stress by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels and increasing superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) expression. Meanwhile, catalpol also inhibited cell apoptosis, decreased the expression of B-cell lymphoma 2 (Bcl-2) - associated X (Bax), caspase 3 and caspase 9, and increased the expression of Bcl-2. This study found that catalpol activates AMP-activated protein kinase (AMPK) signaling pathway and inhibit mammalian target of rapamycin (mTOR) phosphorylationthe. In a further study, after inhibiting AMPK with dorsomorphin, the anti-inflammatory effects of catalpol were significantly reduced. Therefore, catalpol ameliorates LPS-induced inflammatory response by activating AMPK/mTOR signaling pathway in IEC-6 cells.

Transcriptomic analysis of yak longissimus dorsi muscle identifies genes associated with tenderness

Meat tenderness is an important sensory index when consumers choose meat products, which determines the value of meat products and consumers' buying intentions. Yak meat is rich in nutrition and unique in flavor, which is favored by consumers. However, its meat has the deficiencies of low tenderness and poor taste, which has a negative impact on the value of its meat products and customer satisfaction. To identify the genes affecting the yak meat tenderness, we used RNA-seq to analyze the longissimus dorsi muscle of yaks with different tenderness, screened a total of 1120 differentially expressed genes (DEGs). Meanwhile, 23 pathways were significantly enriched. By further analysis, we identified eight genes related to yak meat tenderness (WNT5A, ARID5B, SERPINE1 KLHL40, RUNX1, MAFF, RFX7 and ARID5A). Notably, SERPINE1 was involved in the significant enrichment pathways of 'complement and coagulation cascade pathway', 'HIF-1 signaling pathway' and 'AGE-RAGE signaling pathway in diabetic complications' which can regulate meat tenderness. This implies that SERPINE1 may play an important regulatory role among them. The DEGs associated with yak meat quality screened in this work will be helpful to identify potential biomarkers related to meat tenderness.

Dietary melatonin positively impacts the immune system of crayfish, Cherax destructor, as revealed by comparative proteomics analysis

Melatonin, an indoleamine with various biological activities, is being used increasingly in the aquaculture industry for its broad immune effects. Cherax destructor is an emerging economically cultured crayfish that faces many problems in the breeding process. Previous work found that dietary melatonin has positive effects on the growth and immunity of C. destructor, but the specific mechanism involved remained unclear. In this study, proteomics was used to determine the mechanism of action of melatonin in C. destructor. Results showed that dietary melatonin resulted in decreased levels of hydrogen peroxide, alanine aminotransferase, and aspartate aminotransferase, but increased levels of glutathione peroxidase, acid phosphatase, and glutathione S-transferases. In total, 608 proteins were differentially expressed (418 upregulated and 190 downregulated), and were enriched in three main categories: innate immunity (B cell receptor signaling pathway and natural killer cell-mediated cytotoxicity), glucose metabolism (pentose phosphate pathway, pentose and glucuronate interconversions, and propionate metabolism), and amino acid metabolism (valine, leucine, and isoleucine degradation, and cysteine and methionine metabolism). In addition, dietary melatonin was also involved in the regulation of the mTOR signaling pathway, and upregulated the expression of genes encoding key factors, such as Ras-related GTP-binding protein A/B, eukaryotic initiation factor 4E, eukaryotic initiation factor 4E-binding protein, and p70 ribosomal S6 kinase. Overall, this study demonstrates the role of melatonin in the physiological regulation of C. destructor, laying the foundation for the development of melatonin as a feed additive in the aquaculture of this species.

Fatty acid metabolism disorders and potential therapeutic traditional Chinese medicines in cardiovascular diseases

Cardiovascular diseases are currently the primary cause of mortality in the whole world. Growing evidence indicated that the disturbances in cardiac fatty acid metabolism are crucial contributors in the development of cardiovascular diseases. The abnormal cardiac fatty acid metabolism usually leads to energy deficit, oxidative stress, excessive apoptosis, and inflammation. Targeting fatty acid metabolism has been regarded as a novel approach to the treatment of cardiovascular diseases. However, there are currently no specific drugs that regulate fatty acid metabolism to treat cardiovascular diseases. Many traditional Chinese medicines have been widely used to treat cardiovascular diseases in clinics. And modern studies have shown that they exert a cardioprotective effect by regulating the expression of key proteins involved in fatty acid metabolism, such as peroxisome proliferator-activated receptor α and carnitine palmitoyl transferase 1. Hence, we systematically reviewed the relationship between fatty acid metabolism disorders and four types of cardiovascular diseases including heart failure, coronary artery disease, cardiac hypertrophy, and diabetic cardiomyopathy. In addition, 18 extracts and eight monomer components from traditional Chinese medicines showed cardioprotective effects by restoring cardiac fatty acid metabolism. This work aims to provide a reference for the finding of novel cardioprotective agents targeting fatty acid metabolism.

Potential Benefits of Antioxidant Phytochemicals in Type 2 Diabetes

The clinical relationship between diabetes and inflammation is well established. Evidence clearly indicates that disrupting oxidant-antioxidant equilibrium and elevated lipid peroxidation could be a potential mechanism for chronic kidney disease associated with type 2 diabetes mellitus (T2DM). Under diabetic conditions, hyperglycemia, especially inflammation, and increased reactive oxygen species generation are bidirectionally associated. Inflammation, oxidative stress, and tissue damage are believed to play a role in the development of diabetes. Although the exact mechanism underlying oxidative stress and its impact on diabetes progression remains uncertain, the hyperglycemia-inflammation-oxidative stress interaction clearly plays a significant role in the onset and progression of vascular disease, kidney disease, hepatic injury, and pancreas damage and, therefore, holds promise as a therapeutic target. Evidence strongly indicates that the use of multiple antidiabetic medications fails to achieve the normal range for glycated hemoglobin targets, signifying treatment-resistant diabetes. Antioxidants with polyphenols are considered useful as adjuvant therapy for their potential anti-inflammatory effect and antioxidant activity. We aimed to analyze the current major points reported in preclinical, in vivo, and clinical studies of antioxidants in the prevention or treatment of inflammation in T2DM. Then, we will share our speculative vision for future diabetes clinical trials.

Stress can affect mitochondrial energy metabolism and AMPK/SIRT1 signaling pathway in rats

OBJECTION

To investigate the potential link between aberrant mitochondrial energy metabolism mediated by the AMPK/SIRT1 pathway and the etiology of anxiety disorders.

METHODS

The anxiety rat model was established by uncertain empty water bottle（UEWB）stress. Rats were submitted behavioral tests on the seventh, fourteenth, and twenty-first days and had the prefrontal cortex and amygdala removed for biochemical tests. The morphological alterations of the mitochondria in the medial prefrontal cortex and amygdala were examined by using a transmission electron microscope. Expression levels of AMPK, SIRT1, PGC-1, NRF-1 and NRF-2 were tested by western-blot analysis. ATP, respiratory chain complex and caspase enzyme expressions were tested by neurochemical and biochemical assays.

RESULTS

Rats showed anxiety-like behavior after being exposed to the uncertain empty water bottle (UEWB) stress model. In model rats, mitochondrial structure is damaged, mitochondrial energy metabolism is decreased, and the expression of proteins associated with AMPK/SIRT1 pathway is significantly reduced in the brain.

CONCLUSION

The level of mitochondrial energy metabolism correlates with anxiety-like behavior. The main mechanism of anxiety disorder is a disturbance of mitochondrial energy metabolism, which might be related to AMPK/SIRT1 pathway.

Geniposide ameliorates acute kidney injury via enhancing the phagocytic ability of macrophages towards neutrophil extracellular traps

Acute kidney injury (AKI) is a clinically serious disorder associated with high mortality rates and an increased risk of progression to end-stage renal disease. As an essential supportive treatment for patients with respiratory failure, mechanical ventilation not only save many critically ill patients, but also affect glomerular filtration function by changing renal hemodynamics, neurohumoral and positive end-expiratory pressure, eventually leading to AKI. AMP-activated protein kinase (AMPK), a crucial energy homeostasis regulator, could enhance macrophage phagocytic ability and inhibit inflammation, but whether it can engulf neutrophil extracellular traps (NETs) and alleviate mechanical ventilation-associated AKI is still unclear. In this study, we found that geniposide significantly ameliorated histopathological damage, reduced serum Cre and BUN levels. Besides, geniposide can also induce AMPK activation and enhance macrophage phagocytic ability toward NETs. Moreover, geniposide can markedly reduce the levels of high mobility group box 1 (HMGB1), and these effects were dependent on AMPK-PI3K/Akt signaling. Altogether, these results indicated that geniposide promoted macrophage efferocytosis by inducing AMPK-PI3K/Akt signaling activation, clearing NETs and ameliorating AKI.

Raspberry ketone ameliorates nonalcoholic fatty liver disease in rats by activating the AMPK pathway

The current study aimed to investigate the effect of orally administered raspberry ketone (RK) on ameliorating nonalcoholic fatty liver disease (NAFLD) induced in rats by high-fat high-fructose diet (HFFD) in comparison to calorie restriction (CR) regimen. Thirty male Wistar rats were divided into two experimental groups; one was fed normal chow diet (NCD, n = 6) for 15 weeks to serve as normal control group and the other group was fed HFFD (n = 24) for 7 weeks to induce NAFLD. After induction, rats in the HFFD group were randomly allocated into four groups (n = 6 rats each). One group continued on HFFD feeding for 8 weeks (NAFLD control group). The remaining 3 groups received NCD, calorie-restricted diet, or NCD along with RK (55 mg/kg/day, orally) for 8 weeks. Like CR, RK effectively attenuated NAFLD and ameliorated the changes attained by HFFD. RK upregulated the expression of the phosphorylated AMP-activated protein kinase (P-AMPK) and fatty acid oxidation factors; peroxisome proliferator-activated receptor alpha (PPAR-α) and carnitine palmitoyltransferase-1 (CPT-1) and downregulated lipogenic factors; sterol regulatory element-binding protein-1c (SREBP-1c) and fatty acid synthase (FAS) in the hepatic tissue. Also, RK improved lipid profile parameters, liver enzymes and both body and liver tissue weights. Altogether, these findings suggest that oral administration of RK, along with normal diet, ameliorated NAFLD in a way similar to CR. This approach could be an alternative to CR in the management of NAFLD, overcoming the poor compliance to long term CR regimen.

Selenium nanoparticles improve fish sperm quality by enhancing glucose uptake capacity via AMPK activation

Appropriate additives can provide a suitable physiological environment for storage of fish sperm and facilitate the large-scale breeding of endangered species and commercial fish. Suitable additives for fish sperm storage in vitro are required for artificial insemination. This study evaluate the effects of 0.1, 0.5, 1.5, and 4.5 mg/L selenium nanoparticles (SeNPs) on the quality of Schizothorax prenanti and Onychostoma macrolepis sperm storage in vitro at 4 °C for 72 h. We found that 0.5 mg/L SeNPs was a suitable concentration for maintaining the normal physiological state of O. macrolepis sperm during storage at 4 °C (p < 0.05). Higher adenosine triphosphate (ATP) content of O. macrolepis sperm before and after activation was present at that concentration. To further explore the potential mechanism of action of SeNPs on O. macrolepis sperm, western blotting and glucose uptake analyses were performed. The results implied that after 24 h of in vitro preservation, 0.5 mg/L SeNPs significantly improved p-AMPK levels and glucose uptake capacity of O. macrolepis sperm, while compound C (CC), the inhibitor of activated AMP-activated protein kinase (p-AMPK), significantly restricted the function of SeNPs on stored sperm. Similar effects of 0.5 mg/L SeNPs were found on Schizothorax prenanti sperm. Our study demonstrates that SeNPs maintained ATP content and O. macrolepis and Schizothorax prenanti sperm function during storage in vitro for 72 h, possibly because SeNPs enhanced the glucose uptake capacity of sperm by maintaining the level of p-AMPK.