Zhigang Jiang

The Popeye domain-containing protein 1 (Popdc1), also known as Bves, plays a crucial role in maintaining skeletal muscle homeostasis, with its variants leading to limb–girdle muscular dystrophy type R25. Skeletal muscles of patients with the homozygous missense variant of Bves exhibit impaired membrane trafficking, while skeletal muscle fibers in bves^S191F homozygous mutant zebrafish are significantly reduced and disorganized. However, the mechanism by which the absence of bves induces skeletal muscle atrophy remains unclear. In this study, we discovered a novel mechanism whereby bves deficiency drives skeletal muscle atrophy by disrupting mitochondrial structure and function. Our findings indicate that bves knockout leads to a significant decrease in zebrafish’s ability to swim, atrophy of skeletal muscle tissue, loss of cell membrane localization signals, and abnormalities in mitochondrial structure and function. After an 8-week intervention of regular aerobic exercise, the symptoms of skeletal muscle atrophy in bves knockout zebrafish were significantly alleviated, and the expression levels of genes and proteins related to mitochondrial were effectively rescued. These findings establish a connection between bves deficiency-induced disruption of mitochondrial structure and function and the onset and progression of skeletal muscle tissue atrophy symptoms, thereby laying a molecular foundation for exercise rehabilitation strategies in atrophic myopathy.

Coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, represents a major global pandemic of the 21st century, with long-term effects termed long COVID. This systematic review and network meta-analysis (NMA) evaluated pharmacological interventions for adults with long COVID, incorporating randomized controlled trials and adjusted observational studies. Primary outcomes included all-cause mortality, hospitalization, ICU admission, and mechanical ventilation; secondary outcomes covered symptom recovery across five categories, with safety assessed via adverse events. Results from random-effects models showed that saline nasal irrigation (SMD=21.10, 95% CI [16.91, 25.30]), nitrilotriacetic acid trisodium (SMD=7.40 [5.79, 9.01]), tetra sodium pyrophosphate (SMD=3.69 [2.61, 4.77]), and sodium gluconate (SMD=3.01 [1.92, 4.09]) significantly improved anosmia versus control. For thrombosis, rivaroxaban reduced arterial (OR=0.33 [0.01, 8.19]) and venous thrombotic events (OR=0.12 [0.01, 0.97]), while therapeutic-dose anticoagulants lowered thrombotic risks but increased major bleeding events (OR=1.86 [1.19, 2.89]) compared to prophylactic dosing. This NMA provides comparative evidence to guide treatment strategies for long COVID, highlighting the need for further research as new evidence emerges.

The asb5 gene, a member of the Asb protein subfamily characterized by six ankyrin repeat domains, is highly conserved and comprises two subtypes, asb5a and asb5b, in zebrafish. Our previous research has demonstrated that a deficiency of the asb5 gene significantly impairs early cardiac contractile function, highlighting its close relationship with heart development. Zebrafish asb5 expression was disrupted by both morpholino (MO) antisense oligomer-mediated knockdown and a CRISPR-Cas9 system. A high-throughput RNA-Seq analysis was used to analyze the possible molecular regulatory mechanism of asb5 gene deletion leading to left–right (L-R) asymmetry defects in the heart. Whole-mount in situ hybridization (WISH) was conducted to evaluate gene expression patterns of Nodal signaling components and the positions of heart organs. Heart looping was defective in zebrafish asb5 morphants. Rescue experiments in the asb5-deficiency group (inactivating both asb5a and asb5b) demonstrated that the injection of either asb5a-mRNA or asb5b-mRNA alone was insufficient to rectify the abnormal L-R asymmetry of the heart. In contrast, the simultaneous injection of both asb5a-mRNA and asb5b-mRNA successfully rescued the morphological phenotype. A high-throughput RNA-Seq analysis of embryos at 48 h post fertilization (hpf) revealed that numerous genes associated with L-R asymmetry exhibited expression imbalances in the asb5-deficiency group. WISH further confirmed that the expression of genes such as fli1a, acta1b, hand2, has2, prrx1a, notch1b, and foxa3 were upregulated, while the expression of mei2a and tal1 was downregulated. These results indicated that loss of the asb5 gene in zebrafish led to the disordered development of L-R asymmetry in the heart, resulting in an imbalance in the expression of genes associated with the regulation of L-R asymmetry. Subsequently, we examined the expression patterns of classical Nodal signaling pathway-related genes using WISH. The results showed that the midline barrier factor gene lefty1 was downregulated at early stages in the asb5-deficiency group, and the expression of spaw and lefty2, which are specific to the left lateral plate mesoderm (LPM), was disrupted. This study reveals that the two subtypes of the asb5 gene in zebrafish, asb5a and asb5b, interact and jointly regulate the establishment of early cardiac L-R asymmetry through the Nodal-spaw-lefty signaling pathway.

Background: General control nonderepressible 5 (Gcn5) is a lysine acetyltransferase (KAT) that is evolutionarily conserved across eukaryotes, with two homologs (Kat2a and Kat2b) identified in humans and one (Gcn5) in Drosophila. Gcn5 contains a P300/CBP-associated factor (PCAF) domain, a Gcn5-N-acetyltransferase (GNAT) domain, and a Bromodomain, allowing it to regulate gene expression through the acetylation of both histone and non-histone proteins. In Drosophila, Gcn5 is crucial for embryonic development, with maternal Gcn5 supporting early development. However, the functional mechanisms of Gcn5 after the depletion of maternal deposits remain unclear. Methods: Our study employed the Gal4/UAS-RNAi system to achieve whole-body or heart-specific Gcn5 knockdown in Drosophila and selected 96-hour-old surviving larvae for transcriptomic and metabolomic analyses. Results: Omics results revealed that Gcn5 knockdown significantly impacts various metabolic pathways, as well as lysosomes, non-homologous end-joining, Toll and Imd signaling pathways, and circadian rhythms, among others. Furthermore, defects in chitin synthesis may be associated with impaired pupation. Additionally, heart-specific Gcn5 knockdown affected cardiac physiology but appeared to have a potential protective effect against age-related cardiac decline. Conclusions: These findings deepen our understanding of Gcn5’s roles in Drosophila development and provide valuable insights for developing Gcn5-targeted therapies, particularly considering its involvement in various human diseases.

Pygopus (Pygo) has been identified as a specific nuclear co-activator of the canonical Wingless (Wg)/Wnt signaling pathway in Drosophila melanogaster. Pygo proteins consist of two conserved domains: an N-terminal homologous domain (NHD) and a C-terminal plant homologous domain (PHD). The PHD’s ability to bind to di- and trimethylated lysine 4 of histone H3 (H3K4me2/3) appears to be independent of Wnt signaling. There is ongoing debate regarding the significance of Pygo’s histone-binding capacity. Drosophila Pygo orthologs have a tryptophan (W) > phenylalanine (F) substitution in their histone pocket-divider compared to vertebrates, leading to reduced histone affinity. In this research, we utilized CRISPR/Cas9 technology to introduce the Pygo-F773W point mutation in Drosophila, successfully establishing a viable homozygous Pygo mutant line for the first time. Adult mutant flies displayed noticeable abnormalities in reproduction, locomotion, heart function, and lifespan. RNA-seq and cluster analysis indicated that the mutation primarily affected pathways related to immunity, metabolism, and posttranslational modification in adult flies rather than the Wnt signaling pathway. Additionally, a reduction in H3K9 acetylation levels during the embryonic stage was observed in the mutant strains. These findings support the notion that Pygo plays a wider role in chromatin remodeling, with its involvement in Wnt signaling representing only a specific aspect of its chromatin-related functions.

Ankyrin repeat and suppression-of-cytokine-signaling box (Asb) proteins, a subset of ubiquitin ligase E3, include Asb5 with six ankyrin-repeat domains. Zebrafish harbor two asb5 gene isoforms, asb5a and asb5b. Currently, the effects of asb5 gene inactivation on zebrafish embryonic development and heart function are unknown. Using CRISPR/Cas9, we generated asb5a-knockout zebrafish, revealing no abnormal phenotypes at 48 h post-fertilization (hpf). In situ hybridization showed similar asb5a and asb5b expression patterns, indicating the functional redundancy of these isoforms. Morpholino interference was used to target asb5b in wild-type and asb5a-knockout zebrafish. Knocking down asb5b in the wild-type had no phenotypic impact, but simultaneous asb5b knockdown in asb5a-knockout homozygotes led to severe pericardial cavity enlargement and atrial dilation. RNA-seq and cluster analyses identified significantly enriched cardiac muscle contraction genes in the double-knockout at 48 hpf. Moreover, semi-automatic heartbeat analysis demonstrated significant changes in various heart function indicators. STRING database/Cytoscape analyses confirmed that 11 cardiac-contraction-related hub genes exhibited disrupted expression, with three modules containing these genes potentially regulating cardiac contractile function through calcium ion channels. This study reveals functional redundancy in asb5a and asb5b, with simultaneous knockout significantly impacting zebrafish early heart development and contraction, providing key insights into asb5’s mechanism.