NAD+ rescues aging-induced blood-brain barrier damage via the CX43-PARP1 axis.

Blood-brain barrier (BBB) function deteriorates during aging, contributing to cognitive impairment and neurodegeneration. It is unclear what drives BBB leakage in aging and how it can be prevented. Using single-nucleus transcriptomics, we identified decreased connexin 43 (CX43) expression in cadherin-5+ (Cdh5+) cerebral vascular cells in naturally aging mice and confirmed it in human brain samples. Global or Cdh5+ cell-specific CX43 deletion in mice exacerbated BBB dysfunction during aging. The CX43-dependent effect was not due to its canonical gap junction function but was associated with reduced NAD+ levels and mitochondrial dysfunction through NAD+-dependent sirtuin 3 (SIRT3). CX43 interacts with and negatively regulates poly(ADP-ribose) polymerase 1 (PARP1). Pharmacologic inhibition of PARP1 by olaparib or nicotinamide mononucleotide (NMN) supplementation rescued NAD+ levels and alleviated aging-associated BBB leakage. These findings establish the endothelial CX43-PARP1-NAD+ pathway's role in vascular aging and identify a potential therapeutic strategy to combat aging-associated BBB leakage with neuroprotective implications.

Chemical screening links disulfiram with cardiac protection after ischemic injury.

Ischemia-reperfusion injury occurs after reperfusion treatment for patients suffering myocardial infarction, however the underlying mechanisms are incompletely understood and effective pharmacological interventions are limited. Here, we report the identification and characterization of the FDA-approved drug disulfiram (DSF) as a cardioprotective compound. By applying high-throughput chemical screening, we found that DSF decreased H2O2-induced cardiomyocyte death by inhibiting Gasdermin D, but not ALDH1, in cardiomyocytes. Oral gavage of DSF decreased myocardial infarct size and improved heart function after myocardial ischemia-reperfusion injury in rats. Therefore, this work reveals DSF as a potential therapeutic compound for the treatment of ischemic heart disease.

A DUSP6 inhibitor suppresses inflammatory cardiac remodeling and improves heart function after myocardial infarction.

Acute myocardial infarction (MI) results in loss of cardiomyocytes and abnormal cardiac remodeling with severe inflammation and fibrosis. However, how cardiac repair can be achieved by timely resolution of inflammation and cardiac fibrosis remains incompletely understood. Our previous findings have shown that dual-specificity phosphatase 6 (DUSP6) is a regeneration repressor from zebrafish to rats. In this study, we found that intravenous administration of the DUSP6 inhibitor (E)-2-benzylidene-3-(cyclohexylamino)-2,3-dihydro-1H-inden-1-one (BCI) improved heart function and reduced cardiac fibrosis in MI rats. Mechanistic analysis revealed that BCI attenuated macrophage inflammation through NF-κB and p38 signaling, independent of DUSP6 inhibition, leading to the downregulation of various cytokines and chemokines. In addition, BCI suppressed differentiation-related signaling pathways and decreased bone-marrow cell differentiation into macrophages through inhibiting DUSP6. Furthermore, intramyocardial injection of poly (D, L-lactic-co-glycolic acid)-loaded BCI after MI had a notable effect on cardiac repair. In summary, BCI improves heart function and reduces abnormal cardiac remodeling by inhibiting macrophage formation and inflammation post-MI, thus providing a promising pro-drug candidate for the treatment of MI and related heart diseases. This article has an associated First Person interview with the first author of the paper.

Dusp6 deficiency attenuates neutrophil-mediated cardiac damage in the acute inflammatory phase of myocardial infarction.

Dual-specificity phosphatase 6 (DUSP6) serves a specific and conserved function on the dephosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). We previously identified Dusp6 as a regenerative repressor during zebrafish heart regeneration, therefore we propose to investigate the role of this repressor in mammalian cardiac repair. Utilizing a rat strain harboring Dusp6 nonsense mutation, rat neutrophil-cardiomyocyte co-culture, bone marrow transplanted rats and neutrophil-specific Dusp6 knockout mice, we find that Dusp6 deficiency improves cardiac outcomes by predominantly attenuating neutrophil-mediated myocardial damage in acute inflammatory phase after myocardial infarction. Mechanistically, Dusp6 is transcriptionally activated by p38-C/EBPß signaling and acts as an effector for maintaining p-p38 activity by down-regulating pERK and p38-targeting phosphatases DUSP1/DUSP16. Our findings provide robust animal models and novel insights for neutrophil-mediated cardiac damage and demonstrate the potential of DUSP6 as a therapeutic target for post-MI cardiac remodeling and other relevant inflammatory diseases.

A small-molecule cocktail promotes mammalian cardiomyocyte proliferation and heart regeneration.

Zebrafish and mammalian neonates possess robust cardiac regeneration via the induction of endogenous cardiomyocyte (CM) proliferation, but adult mammalian hearts have very limited regenerative potential. Developing small molecules for inducing adult mammalian heart regeneration has had limited success. We report a chemical cocktail of five small molecules (5SM) that promote adult CM proliferation and heart regeneration. A high-content chemical screen, along with an algorithm-aided prediction of small-molecule interactions, identified 5SM that efficiently induced CM cell cycle re-entry and cytokinesis. Intraperitoneal delivery of 5SM reversed the loss of heart function, induced CM proliferation, and decreased cardiac fibrosis after rat myocardial infarction. Mechanistically, 5SM potentially targets α1 adrenergic receptor, JAK1, DYRKs, PTEN, and MCT1 and is connected to lactate-LacRS2 signaling, leading to CM metabolic switching toward glycolysis/biosynthesis and CM de-differentiation before entering the cell-cycle. Our work sheds lights on the understanding CM regenerative mechanisms and opens therapeutic avenues for repairing the heart.

Protocol to identify small molecules promoting rat and mouse cardiomyocyte proliferation based on the FUCCI and MADM reporters.

Discovery of small molecules promoting cardiomyocyte proliferation is important for heart regeneration and related heart disease. Here, we describe a protocol to isolate neonatal rat and mouse cardiomyocytes, infect cardiomyocytes with Tnnt2-mAG-hGeminin (1/110) or Tnnt2-Cre adenovirus, and identify small molecules that promote cardiomyocyte proliferation by high-content microscopy. This protocol can be modified to investigate other pro-proliferation factors in cardiomyocytes and other cell types. For complete details on the use and execution of this protocol, please refer to Du et al. (2022).1.

Overview of Metabolomic Analysis and the Integration with Multi-Omics for Economic Traits in Cattle.

Metabolomics has been applied to measure the dynamic metabolic responses, to understand the systematic biological networks, to reveal the potential genetic architecture, etc., for human diseases and livestock traits. For example, the current published results include the detected relevant candidate metabolites, identified metabolic pathways, potential systematic networks, etc., for different cattle traits that can be applied for further metabolomic and integrated omics studies. Therefore, summarizing the applications of metabolomics for economic traits is required in cattle. We here provide a comprehensive review about metabolomic analysis and its integration with other omics in five aspects: (1) characterization of the metabolomic profile of cattle; (2) metabolomic applications in cattle; (3) integrated metabolomic analysis with other omics; (4) methods and tools in metabolomic analysis; and (5) further potentialities. The review aims to investigate the existing metabolomic studies by highlighting the results in cattle, integrated with other omics studies, to understand the metabolic mechanisms underlying the economic traits and to provide useful information for further research and practical breeding programs in cattle.

Lactobionic acid-modified phycocyanin nanoparticles loaded with doxorubicin for synergistic chemo-photodynamic therapy.

Phycocyanin (PC) is considered to be an effective natural photosensitizer, but it has not been well utilized as its inefficient biostability and intracellular accumulation. To overcome these limitations, the nano-sized PC particles (LAPC/DOX) were developed by grafting with lactobionic acid (LA) and loading with doxorubicin (DOX). Compared to the PC solution, the storage-stability and photostability of PC particles were remarkably increased, and the formation of nanoparticles further improved its biostability. Besides, CLSM images confirmed that LA could also enhance cellular uptake, resulting in more intracellular PC and DOX accumulation. MTT assay revealed that LAPC/DOX caused the highest cytotoxicity by combined chemo-photodynamic therapy. Finally, LAPC/DOX could efficiently accumulate and spread in tumoral multicellular spheroids, resulting in the enhanced growth inhibition. Overall, the LAPC/DOX is effective in cancer treatment, which provides new insights for the usage of functional proteins in vivo.

Molecular regulation of myocardial proliferation and regeneration.

Heart regeneration is a fascinating and complex biological process. Decades of intensive studies have revealed a sophisticated molecular network regulating cardiac regeneration in the zebrafish and neonatal mouse heart. Here, we review both the classical and recent literature on the molecular and cellular mechanisms underlying heart regeneration, with a particular focus on how injury triggers the cell-cycle re-entry of quiescent cardiomyocytes to replenish their massive loss after myocardial infarction or ventricular resection. We highlight several important signaling pathways for cardiomyocyte proliferation and propose a working model of how these injury-induced signals promote cardiomyocyte proliferation. Thus, this concise review provides up-to-date research progresses on heart regeneration for investigators in the field of regeneration biology.

Mink is a highly susceptible host species to circulating human and avian influenza viruses.

Pandemic influenza, typically caused by the reassortment of human and avian influenza viruses, can result in severe or fatal infections in humans. Timely identification of potential pandemic viruses must be a priority in influenza virus surveillance. However, the range of host species responsible for the generation of novel pandemic influenza viruses remains unclear. In this study, we conducted serological surveys for avian and human influenza virus infections in farmed mink and determined the susceptibility of mink to prevailing avian and human virus subtypes. The results showed that farmed mink were commonly infected with human (H3N2 and H1N1/pdm) and avian (H7N9, H5N6, and H9N2) influenza A viruses. Correlational analysis indicated that transmission of human influenza viruses occurred from humans to mink, and that feed source was a probable route of avian influenza virus transmission to farmed mink. Animal experiments showed that mink were susceptible and permissive to circulating avian and human influenza viruses, and that human influenza viruses (H3N2 and H1N1/pdm), but not avian viruses, were capable of aerosol transmission among mink. These results indicate that farmed mink could be highly permissive "mixing vessels" for the reassortment of circulating human and avian influenza viruses. Therefore, to reduce the risk of emergence of novel pandemic viruses, feeding mink with raw poultry by-products should not be permitted, and epidemiological surveillance of influenza viruses in mink farms should be urgently implemented.

Ablation of protein phosphatase 5 (PP5) leads to enhanced both bone and cartilage development in mice.

This study aimed to investigate the role of protein phosphatase 5 (PP5) on bone and cartilage development using both in vivo and in vitro approaches. Six- to 8-week- old male PP5 knockout mice (KO) and their wild-type (WT) littermate controls were randomly selected for this study, and their body weights and bone (femur) lengths were measured. Micro-computed tomography scanning (Micro-CT) was performed to determine femoral bone density and micro-architecture. Mesenchymal stem cells (MSCs) isolated from bone marrow were used to examine the effects of PP5 on osteogenesis in vitro. Whole-mount Alcian blue and Alizarin red staining were used to detect cartilage formation in newborn vertebrae, limbs, and feet. Hematoxylin and eosin (H&E) staining was performed to determine growth plate thickness. Real-time PCR analysis, western blotting, and immunohistochemistry were used to detect the expression of genes and proteins in bone marrow-derived MSCs as well as in bone and cartilage tissues. The results showed PP5 KO mice exhibited significantly reduced body weight and shorter femur length compared to WT controls. The KO mice also had significantly higher volumetric bone mineral density (BMD), trabecular bone volume, and cortical thickness in the femur. The deficiency of PP5 significantly enhanced the formation of cartilage in vertebrae, limbs, and feet. In addition, KO mice possessed a wider distal femur growth plates containing significantly more chondrocytes than WT mice. Furthermore, higher expressions of several cartilage-specific genes were observed in the articular cartilage of PP5 KO mice. Immunohistochemical labeling of growth plates demonstrated that phospho-PPARγ, Runx1, and Runx2 levels were considerably higher in the KO mice. In conclusion, PP5 is a significant negative regulator on the regulation of bone and cartilage development.