Acta biochimica et biophysica Sinica最新文献

Dorsal root ganglion (DRG) neurons are responsible for the primary detection and transmission of peripheral noxious stimuli, mainly pain and itch. However, as two distinct noxious sensations, how DRG neurons respond differently to and code pain and itch is still an attractive topic. Here, we investigate the response and activation spectrum of DRG neurons under peripheral pain and itch stimuli using in vivo two-photon calcium imaging and find differences in the response intensity to pain and itch between multisensory neurons (both pain and itch) and single-sensory neurons (either pain or itch). In addition, single-cell RNA sequencing (scRNA-seq) is used to reveal the heterogeneity of distinct subpopulations on the basis of their expressions of pain- or itch-related marker genes and to determine the similarities and differences in their transcriptomic changes under chronic pain and itch. Our results show that primary sensory neurons with different sensory patterns respond differently to the same nociceptive stimuli. Additionally, distinct clusters of neurons exhibit unique transcriptomic changes in the development of chronic pain and itch, which may offer new insights for treating these conditions.

Myocardial infarction leads to cardiomyocyte loss, and the compromised proliferative capacity of cardiomyocytes after birth hinders the process of heart repair, ultimately culminating in heart failure. Extracellular vesicles (EVs), known as cell-secreted "messengers", play a pivotal role in tissue pathophysiology. Here, we report the novel finding that myocardial tissue-derived vesicles from mice on postnatal day 8 (P8-EVs) possess the potential to modulate cardiomyocyte proliferation. Notably, direct administration of EVs derived from day 1 or day 8 (P1/P8) myocardial tissue does not impact neonatal cardiomyocyte proliferation or myocardial repair in mice with myocardial infarction. However, by leveraging bioinformatics, high-throughput omics, and single-cell analyses, we unveil that P8-EVs are enriched with the key gene p21 activated kinase 2 (Pak2), a regulator of macrophage reparative function. Through single-cell sequencing of P8 myocardial tissue, we identify macrophages as the cell type with the highest Pak2 content, implying a close association between macrophages and P8-EV function. Intriguingly, further investigations reveal that P8-EVs significantly promote M1-like polarization, augment phagocytosis, and affect factor secretion in macrophages. Co-culture experiments demonstrate that P8-EV-treated macrophages strongly suppress neonatal cardiomyocyte proliferation, and this effect is effectively reversed by a Pak2 inhibitor. Additional pathway intervention experiments reveal that P8-EVs activate the downstream Erk1/2 signaling pathway of Pak2. Collectively, our findings indicate that P8-EVs regulate macrophage paracrine activities through the Pak2-Erk1/2 axis, thereby influencing cardiomyocyte proliferation. This finding reveals a potential underlying mechanism for the compromised proliferative capacity of cardiomyocytes in adult mice.

Atherosclerosis (AS) is a chronic inflammatory disease characterized by the accumulation of lipid-rich plaques in arterial walls, leading to cardiovascular events such as myocardial infarction and stroke. Macrophage pyroptosis, a form of programmed cell death driven by the NLRP3 inflammasome and caspase-1 activation, plays a critical role in the progression and destabilization of atherosclerotic plaques. This review explores the molecular mechanisms underlying macrophage pyroptosis and their significant contributions to AS pathogenesis. Recent advancements have highlighted the therapeutic potential of targeting key components of the pyroptotic pathway, including the use of nanotechnology to increase drug delivery specificity. These strategies are promising for reducing inflammation, stabilizing plaques, and mitigating the clinical impact of AS. Future studies should focus on translating these findings into clinical applications to develop effective treatments that can halt or reverse AS progression by modulating macrophage pyroptosis.

MicroRNAs (miRNAs) have emerged as essential regulators that play important roles in the development of multiple systems. Recent studies have identified significant roles for miRNAs in the progression of cardiac hypertrophy. This study aims to investigate the effects of miR-133b-3p on angiotensin II (Ang II)-induced cardiac hypertrophy and apoptosis, as well as explore its underlying mechanisms. Our experimental results reveal that miR-133b-3p expression is significantly decreased in both animal and cell models of cardiac hypertrophy induced by Ang II. Overexpression of miR-133b-3p reverses the hypertrophic manifestations and apoptosis induced by Ang II. Through bioinformatics analysis and dual-luciferase reporter assays, CDIP1 (cell death inducing p53 target 1) is identified as a direct target of miR-133b-3p, and the overexpression of miR-133b-3p reduces CDIP1 expression. Additionally, CDIP1 silencing suppresses cardiomyocyte hypertrophy and apoptosis induced by Ang II. In summary, these results suggest that miR-133b-3p may serve as a potential diagnostic marker for cardiac hypertrophy and that the upregulation of miR-133b-3p inhibits cardiac hypertrophy by targeting CDIP1.

Ageing is an independent factor for cognitive dysfunction. Ageing-associated alterations in the gut microbiota also affect cognition. The present study is designed to investigate changes in the gut microbiota and their participation in ageing-associated cognitive impairment. Both 10-week-old and 18-month-old mice are used. Mouse cognition is examined by novel object recognition and T-maze tests. Mouse feces are collected for sequencing and transplantation. Protein expression in the mouse intestine and hippocampus is studied using immunohistochemistry and immunofluorescence staining. Senescent neurons are induced by hydrogen peroxide in vitro. The cell lysates are used for western blot analysis and adenosine triphosphate (ATP) measurement. Our results show that 18-month-old mice exhibit cognitive dysfunction compared with young mice. In aged mice, transplanting the microbiota of young mice increases the protein presence of synaptophysin in the hippocampus and partially restores cognition. The protein expressions of mucin-2 and E-cadherin in the intestine are reduced in aged mice but are increased by transplantation. Gut microbiota analyses reveal that the reduced abundance of the microbe Bacilli-Lactobacillales-Lactobacillaceae-Lactobacillus in aged mice is restored by transplantation. Fecal microbiota transplantation in young mice increases the serum level of acetic acid in aged mice. Hydrogen peroxide stimulation induces senescence and reduces the protein expression levels of synaptophysin and acetyl-coenzyme A synthetase member 2 (ACSS2) in primary neurons. Incubation with acetic acid upregulates the protein expressions of ACSS2 and synaptophysin and further increases ATP production in senescent neurons. In summary, gut microbiota transplantation increases the abundance of Lactobacillales, elevates serum acetic acid level, and improves cognitive function in aged mice. Gut microbiota transplantation has therapeutic importance for ageing-associated cognitive decline.

The proliferative capacity of cardiomyocytes is limited in adult mammals, and replacing lost tissue following acute ischemic injury is challenging. Previous studies have demonstrated that miR-199a-3p can promote cardiomyocyte proliferation, but the exact mechanism by which this occurs remains unclear, although multiple targets of miR-199a-3p have been identified. We recently showed that very-low-density-lipoprotein receptor (Vldlr) inhibits cardiomyocyte proliferation, and in this study we aim to test whether Vldlr is a functional target gene of miR-199a-3p. 3'UTR reporter assays demonstrate that miR-199a-3p directly binds to the 3'UTR of Vldlr and inhibits its translation. Overexpressing Vldlr blunts the pro-proliferative effect of miR-199a-3p on cardiomyocytes, suggesting that Vldlr is indeed a functional target of miR-199a-3p. Mechanistically, Vldlr reduces S807/811 phosphorylation of RB1, and inhibiting CDK4/6 to prevent RB1 phosphorylation can block the pro-proliferative effect of both Vldlr knockdown and miR-199a-3p, suggesting that RB1 phosphorylation is required for the cardiomyocyte proliferation induced by miR-199a-3p and Vldlr knockdown. The findings of this study reveal Vldlr as a novel functional target of miR-199a-3p in cardiomyocytes and identify RB1 as a downstream effector of cardiomyocyte proliferation. The identification of the role of the miR-199a-3p- Vldlr-RB1 axis in cardiomyocyte proliferation may provide potential therapeutic targets for cardiac regenerative medicine.

Pyroptosis is a regulated inflammatory cell death process that plays an essential role in various diseases. This study investigates the role of proline/serine-rich coiled-coil protein 1 (PSRC1) in pyroptosis and inflammation in macrophages. This study reports that PSRC1 expression is decreased in pyroptotic macrophages and that knockout of PSRC1 exacerbates pyroptosis and inflammation. PSRC1 overexpression alleviates pyroptosis and inflammation in macrophages. RNA-seq analysis reveals that PSRC1 regulates the expression of genes involved in the extracellular matrix (ECM). Specifically, PSRC1 downregulates the expression of periostin (POSTN), an ECM component. Knockdown of POSTN suppresses macrophage pyroptosis mediated by low expression of PSRC1. These findings suggest that PSRC1 can alleviate pyroptosis and inflammation in bone marrow-derived macrophages (BMDMs) by regulating the ECM and negatively regulating POSTN. This study provides insights into the role of PSRC1 in macrophage pyroptosis and identifies a potential target for the treatment of inflammatory diseases. Further research is needed to confirm these findings in vivo and in various disease models.

Traumatic brain injury (TBI) is a recognized global public health problem. However, there are still limitations in the available therapeutic approaches and a lack of clinically effective drugs. Therefore, an in-depth exploration of the secondary pathological mechanism of TBI and the identification of new effective drugs are urgently needed. Cannabidiol (CBD), a component derived from the cannabis plant, has potential therapeutic effects on neurological diseases and has received increasing attention. However, few reports on CBD intervention in TBI patients exist. Here, we use the Feeney free-fall method to establish a rat TBI model. CBD significantly improves neurological deficit scores, neuronal damage and blood-brain barrier permeability in rats and significantly inhibits the expressions of the brain injury markers S-100β and NSE. Mechanistically, CBD attenuates TBI-induced astrocyte activation, reduces inflammation, and attenuates the expressions of inflammatory prostaglandin system indicators. The use of TG6-10-1 (EP2 inhibitor) and H-89 (PKA inhibitor) indicates that CBD attenuates TBI-induced neurological damage via the PGE ₂-EP2-cAMP-PKA signaling pathway. Overall, this research provides a novel drug candidate for the treatment of clinical brain trauma.

Amycolatopsis mediterranei U32 is an industrial strain capable of producing therapeutically useful rifamycin SV. In early days of fermentation studies, nitrate was found to increase the yield of rifamycin along with globally, affecting both carbon and nitrogen metabolism in favor of antibiotic biosynthesis; thus, the nitrate-stimulating effect (NSE) hypothesis was proposed. Although GlnR is likely the master regulator of the pleotropic effect of NSE, the global metabolism affected by NSE has never been systematically examined. In this study, we use mass spectrometry-based metabolomics to quantitatively monitor the metabolomic responses of A. mediterranei U32 to nitrate supplementation. The concentrations of many metabolites involved in central carbon metabolism, including glucose 6-phosphate, glucose 1-phosphate, UDP-glucose, and acetyl-coenzyme A, decrease significantly after the addition of 80 mM potassium nitrate to the medium. We find that the rifamycin SV production yield could be increased by the addition of glucose during the logarithmic growth phase. Moreover, at multiple time points during glucose supplementation in the mid- and late-exponential phases, the yield of rifamycin SV further increases, reaching 354.3%. Quantitative real-time PCR assays of the key genes corresponding to the synthesis of the rifamycin SV precursor combined with data from metabolomics analysis confirm that carbon source deficiency is compensated for after glucose supplementation and that the expression of genes involved in the pathway of 3-amino-5-hydroxybenzoic acid synthesis by UDP-glucose and glutamine is significantly increased. This preliminary exploration of dynamic metabolomic profiles has the potential to increase our understanding of the NSE.