Phosphoproteomic Analysis of Neonatal Regenerative Myocardium Revealed Important Roles of Checkpoint Kinase 1 via Activating Mammalian Target of Rapamycin C1/Ribosomal Protein S6 Kinase b-1 Pathway

Targeting Viperin prevents coxsackievirus B3-induced acute heart failure

Coxsackievirus B3 (CVB3)-induced acute heart failure (AHF) is a common cause of cardiogenic death in young- and middle-aged people. However, the key molecular events linking CVB3 to AHF remain largely unknown, resulting in a lack of targeted therapy strategies thus far. Here, we unexpectedly found that Viperin deficiency does not promote CVB3 infection but protects mice from CVB3-induced AHF. Importantly, cardiac-specific expression of Viperin can induce cardiac dysfunction. Mechanistically, CVB3-encoded 3C protease rescues Viperin protein expression in cardiomyocytes by lowering UBE4A. Viperin in turn interacts with and reduces STAT1 to activate SGK1-KCNQ1 signaling, and eventually leads to cardiac electrical dysfunction and subsequent AHF. Furthermore, we designed an interfering peptide VS-IP1, which blocked Viperin-mediated STAT1 degradation and therefore prevented CVB3-induced AHF. This study established the first signaling link between CVB3 and cardiac electrical dysfunction, and revealed the potential of interfering peptides targeting Viperin for the treatment of CVB3-induced AHF.

Molecular gatekeepers of endogenous adult mammalian cardiomyocyte proliferation

Irreversible cardiac fibrosis, cardiomyocyte death and chronic cardiac dysfunction after myocardial infarction pose a substantial global health-care challenge, with no curative treatments available. To regenerate the injured heart, cardiomyocytes must proliferate to replace lost myocardial tissue - a capability that adult mammals have largely forfeited to adapt to the demanding conditions of life. Using various preclinical models, our understanding of cardiomyocyte proliferation has progressed remarkably, leading to the successful reactivation of cell cycle induction in adult animals, with functional recovery after cardiac injury. Central to this success is the targeting of key pathways and structures that drive cardiomyocyte maturation after birth - nucleation and ploidy, sarcomere structure, developmental signalling, chromatin and epigenetic regulation, the microenvironment and metabolic maturation - forming a complex regulatory framework that allows efficient cellular contraction but restricts cardiomyocyte proliferation. In this Review, we explore the molecular pathways underlying these core mechanisms and how their manipulation can reactivate the cell cycle in cardiomyocytes, potentially contributing to cardiac repair.

Mendelian randomization provides a multi-omics perspective on the regulation of genes involved in ribosome biogenesis in relation to cardiac structure and function

BACKGROUND

Ribosome biogenesis (RiboSis) is a complex process for generating ribosomes, the cellular machinery responsible for protein synthesis. Dysfunctional RiboSis can disrupt cardiac structure and function, contributing to cardiovascular diseases. This study employed a Mendelian randomization (MR) approach, integrating multi-omics data, to investigate the relationship between RiboSis-related genes and standard cardiac structure and function.

METHODS

We utilized summary stats for methylation, RNA splicing, and gene expression, and UK Biobank cardiopulm MRI genetic associations (N = 41,135). MR evaluated RiboSis gene features against traits, complemented by hypothesis prioritization for multi-trait colocalization (HyPrColoc) and colocalization. Composite scores ranked RiboSis genes, and phenome-wide association study (PheWAS) with scQTLbase instrumental variables (IVs) confirmed results.

RESULTS

We identified 15 RiboSis-related genes: HEATR1, SENP3, ERI1, ERCC2, TSR1, UTP11, DDX17, SMARCB1, NIP7, ERAL1, NOP56, RPL10A, EIF6, EXOSC9, and NOP58. Notably, HEATR1 and SENP3 were ranked in the top quartile (Q1), scoring 25. In validation cohort, 12 genes associated with cardiac structures, functions, diseases. Only ERAL1, TSR1, and NIP7 lacked significant associations with cardiac traits.

CONCLUSION

Our multi-omics MR analysis identified 15 RiboSis-related genes associated with cardiac risk, with 12 further validated through gene set enrichment analysis. These findings suggest a link between RiboSis and cardiac health, enhancing understanding of cardiac disease mechanisms.

New Types of Post-Translational Modification of Proteins in Cardiovascular Diseases

Post-translational modifications (PTMs), which are covalent alterations of proteins after their synthesis, are critical for their proper function and the maintenance of cellular physiology. The significance of PTMs in the context of cardiovascular diseases (CVDs) has been increasingly recognized due to their potential to influence protein stability, activity, and localization, thereby affecting the progression of CVDs. The identification and understanding of PTMs in CVDs at the molecular level are vital for the discovery of new biomarkers and new targets for clinical interventions. This article provides a comprehensive overview of the role and mechanisms of new types of PTMs, such as acetylation, crotonylation, succinylation, S-nitrosylation, malonylation, S-palmitonylation, β-hydroxybutyrylation and lactylation, in CVDs, highlighting their importance in advancing diagnostic and therapeutic approaches for CVDs.

FNDC5/irisin mitigates the cardiotoxic impacts of cancer chemotherapeutics by modulating ROS-dependent and -independent mechanisms

Cardiotoxicity remains a major limiting factor in the clinical implementation of anthracycline chemotherapy. Though the etiology of doxorubicin-dependent heart damage has yet to be fully elucidated, the ability of doxorubicin to damage DNA and trigger oxidative stress have been heavily implicated in the pathogenesis of chemotherapy-associated cardiomyopathy. Here, we demonstrate that fibronectin type III domain-containing protein 5 (FNDC5), the precursor protein for myokine irisin, is depleted in the hearts of human cancer patients or mice exposed to chemotherapeutics. In cardiomyocytes, restoration of FNDC5 expression was sufficient to mitigate reactive oxygen species (ROS) accumulation and apoptosis following doxorubicin exposure, effects dependent on the irisin encoding domain of FNDC5 as well as signaling via the putative irisin integrin receptor. Intriguingly, we identified two parallel signaling cascades impacted by FNDC5 in cardiomyocytes: the ROS-driven intrinsic mitochondrial apoptosis pathway and the ROS-independent Ataxia Telangiectasia and Rad3-Related Protein (ATR)/Checkpoint Kinase 1 (Chk1) pathway. In fact, FNDC5 forms a co-precipitable complex with Chk1 alluding to possible intracellular actions for this canonically membrane-associated protein. Whereas FNDC5 overexpression in murine heart was cardioprotective, introduction of FNDC5-targeted shRNA into the myocardium was sufficient to trigger Bax up-regulation, ATR/Chk1 activation, oxidative stress, cardiac fibrosis, loss of ventricular function, and compromised animal survival. The detrimental impact of FNDC5 depletion on heart function could be mitigated via treatment with a Chk1 inhibitor identifying Chk1 hyperactivity as a causative factor in cardiac disease. Though our data point to the potential clinical utility of FNDC5/irisin-targeted agents in the treatment of chemotherapy-induced cardiotoxicity, we also found significant down regulation in FNDC5 expression in the hearts of aged mice that attenuated the cardioprotective impacts of FNDC5 overexpression following doxorubicin exposure. Together our data underscore the importance of FNDC5/irisin in maintenance of cardiac health over the lifespan.

Targeting NLRC5 in cardiomyocytes protects postinfarction cardiac injury by enhancing autophagy flux through the CAVIN1/CAV1 axis

NOD-like receptor (NLR) family proteins are implicated in various cardiovascular diseases. However, the precise role of NLRC5, the largest member of this family, in myocardial infarction (MI) remains poorly understood. This study reveals that NLRC5 is upregulated in the hearts of both patients with MI and MI mice. Silencing NLRC5 in cardiomyocytes impairs cardiac repair and functional recovery, while its overexpression enhances these processes. Furthermore, NLRC5 promotes autophagy in cardiomyocytes, and its protective effects are diminished upon autophagy inhibition. Mechanistically, NLRC5 interacts with CAVIN1, facilitating its degradation and subsequent downregulation of CAV1, which in turn increases the expression of the ATG12-ATG5 complex to stimulate autophagy. Conversely, CAV1 overexpression partially suppresses autophagy and attenuates the improvements in cardiac function observed in NLRC5-overexpressing MI hearts. This study highlights the critical regulatory role of NLRC5 in modulating cardiomyocyte autophagy flux, suggesting that NLRC5 activation may represent a promising therapeutic strategy for MI.

CHK1 attenuates cardiac dysfunction via suppressing SIRT1-ubiquitination

BACKGROUND

Mitochondrial dysfunction is linked to myocardial ischemia-reperfusion (I/R) injury. Checkpoint kinase 1 (CHK1) could facilitate cardiomyocyte proliferation, however, its role on mitochondrial function in I/R injury remains unknown.

METHODS

To investigate the role of CHK1 on mitochondrial function following I/R injury, cardiomyocyte-specific knockout/overexpression mouse models were generated. Adult mouse cardiomyocytes (AMCMs) were isolated for in vitro study. Mass spectrometry-proteomics analysis and protein co-immunoprecipitation assays were conducted to dissect the molecular mechanism.

RESULTS

CHK1 was downregulated in myocardium post I/R and AMCMs post oxygen-glucose deprivation/re‑oxygenation (OGD/R). In vivo, CHK1 overexpression protected against I/R induced cardiac dysfunction, while heterogenous CHK1 knockout exacerbated cardiomyopathy. In vitro, CHK1 inhibited OGD/R-induced cardiomyocyte apoptosis and bolstered cardiomyocyte survival. Mechanistically, CHK1 attenuated oxidative stress and preserved mitochondrial metabolism in cardiomyocytes under I/R. Moreover, disrupted mitochondrial homeostasis in I/R myocardium was restored by CHK1 through the promotion of mitochondrial biogenesis and mitophagy. Through mass spectrometry analysis following co-immunoprecipitation, SIRT1 was identified as a direct target of CHK1. The 266-390 domain of CHK1 interacted with the 160-583 domain of SIRT1. Importantly, CHK1 phosphorylated SIRT1 at Thr530 residue, thereby inhibiting SMURF2-mediated degradation of SIRT1. The role of CHK1 in maintaining mitochondrial dynamics control and myocardial protection is abolished by SIRT1 inhibition, while inactivated mutation of SIRT1 Thr530 fails to reverse the impaired mitochondrial dynamics following CHK1 knockdown. CHK1 Δ390 amino acids (aa) mutant functioned similarly to full-length CHK1 in scavenging ROS and maintaining mitochondrial dynamics. Consistently, cardiac-specific SIRT1 knockdown attenuated the protective role of CHK1 in I/R injury.

CONCLUSIONS

Our findings revealed that CHK1 mitigates I/R injury and restores mitochondrial dynamics in cardiomyocytes through a SIRT1-dependent mechanism.

Single-Cell Multi-Omics Analysis of In Vitro Post-Ovulatory-Aged Oocytes Revealed Aging-Dependent Protein Degradation

Once ovulated, the oocyte has to be fertilized in a short time window or it will undergo post-ovulation aging (POA), whose underlying mechanisms are still not elucidated. Here, we optimized single-cell proteomics methods and performed single-cell transcriptomic, proteomic, and phosphoproteomic analysis of fresh, POA, and melatonin-treated POA oocytes. POA oocytes showed downregulation of most differentially expressed proteins, with little correlation with mRNA expression, and the protein changes can be rescued by melatonin treatment. MG132 treatment rescued the decreased fertilization and polyspermy rates and upregulated fragmentation and parthenogenesis rates of POA oocytes. MG132-treated oocytes displayed health status at proteome, phosphoproteome, and fertilization ability similar to fresh oocytes, suggesting that protein stabilization might be the underlying mechanism for melatonin to rescue POA. The important roles of proteasome-mediated protein degradation during oocyte POA revealed by single-cell multi-omics analyses offer new perspectives for increasing oocyte quality during POA and improving assisted reproduction technologies.

A meta-analysis and systematic review of myocardial infarction-induced cardiomyocyte proliferation in adult mouse heart

BACKGROUND

The proliferation capacity of adult cardiomyocytes is very limited in the normal adult mammalian heart. Previous studies implied that cardiomyocyte proliferation increases after injury stimulation, but the result is controversial partly due to different methodologies. We aim to evaluate whether myocardial infarction (MI) stimulates cardiomyocyte proliferation in adult mice.

METHODS

A comprehensive literature search was conducted through PubMed/Medline, Embase, and Web of Science databases from 1 January 2000 to 21 December 2023. The SYRCLE's Risk of Bias tool for animal experiments was used to evaluate the quality of the literature by two independent reviewers. Twenty-six studies with cell cycle indicators (Ki67+, PH3+, BrdU/EdU+, and AurkB+) to evaluate cycling cardiomyocytes were collected for a meta-analysis. Another 10 studies with genetic reporter/tracing systems to evaluate cardiomyocyte proliferation were collected for a systematic review.

RESULTS

Evaluating cardiomyocyte proliferation by immunostaining of the cell cycle indicators on heart tissue, the meta-analysis showed that differences of Ki67+, PH3+, and BrdU/EdU+ cycling cardiomyocytes between MI and Sham groups were not statistically significant. In the post-MI heart, the percentages of PH3+, BrdU/EdU+, and AurkB+ cardiomyocytes were not significantly different between the infarct border zone and remote zone. The percentage of Ki67+ cardiomyocytes in the infarct border zone was statistically higher than that in the remote zone. Most of the studies (6 out of 10) using genetic reporter/tracing mouse systems showed that the difference in cardiomyocyte proliferation between MI and Sham groups was not statistically significant. Among the other 4 studies, at least 3 studies could not demonstrate that MI stimulates bona fide cardiomyocyte proliferation because of methodological shortages.

CONCLUSIONS

MI injury increases Ki67+ cycling adult mouse cardiomyocytes in infarct border zone. Very little overwhelming evidence shows that MI stimulates bona fide proliferation in the adult heart.

Analyzing the role of ferroptosis in ribosome-related bone marrow failure disorders: From pathophysiology to potential pharmacological exploitation

Within the last decade, the scientific community has witnessed the importance of ferroptosis as a novel cascade of molecular events leading to cellular decisions of death distinct from apoptosis and other known forms of cell death. Notably, such non- apoptotic and iron-dependent regulated cell death has been found to be intricately linked to several physiological processes as well as to the pathogenesis of various diseases. To this end, recent data support the notion that a potential molecular connection between ferroptosis and inherited bone marrow failure (IBMF) in individuals with ribosomopathies may exist. In this review, we suggest that in ribosome-related IBMFs the identified mutations in ribosomal proteins lead to changes in the ribosome composition of the hematopoietic progenitors, changes that seem to affect ribosomal function, thus enhancing the expression of some mRNAs subgroups while reducing the expression of others. These events lead to an imbalance inside the cell as some molecular pathways are promoted while others are inhibited. This disturbance is accompanied by ROS production and lipid peroxidation, while an additional finding in most of them is iron accumulation. Once lipid peroxidation and iron accumulation are the two main characteristics of ferroptosis, it is possible that this mechanism plays a key role in the manifestation of IBMF in this type of disease. If this molecular mechanism is further confirmed, new pharmacological targets such as ferroptosis inhibitors that are already exploited for the treatment of other diseases, could be utilized to improve the treatment of ribosomopathies.

Cardiomyocyte-derived exosomes promote cardiomyocyte proliferation and neonatal heart regeneration

Heart regeneration was mainly achieved by intrinsic capacity. Exosomes are crucial in cardiovascular disease, yet their involvement in myocardial regeneration remains underexplored. To understand the role of cardiomyocyte-derived exosomes (CM-Exos) in heart regeneration. We established mouse models of myocardial infarction and apical resection in neonates to investigate the potential benefits of exosomes in response to injury. Rab27a knockout (KO) mice were constructed as an exosome decrease model. Distinct fibrosis appears in the infarcted and resection area in the KO mice 21 days after heart injury. The proliferation marker pH 3, Ki67, and Aurora B were detected 3 days after surgery, which decreased in KO mice compared to WT mice. Intravenous injection of CM-Exos increased cardiomyocyte proliferation and partially restored heart function in KO mice. Rab27a knockdown in vitro reduced the expression of pH 3, Ki67, and Aurora B positive cardiomyocytes. However, the supplementation of CM-Exos increased the proliferation of cardiomyocytes. Exosomal miRNA sequencing was subsequently applied, and miR-21-5p was a promising candidate that promoted cardiomyocyte proliferation through its target genes Spry-1 and PDCD4. Intravenous injection of miR-21-5p exhibited similar proliferative effects as CM-Exos. Our results indicate that CM-Exos promotes cardiomyocyte cycle reentry by delivering miR-21-5p, highlighting the endogenous factors of myocardial regeneration.

The de novo purine synthesis enzyme Adssl1 promotes cardiomyocyte proliferation and cardiac regeneration

There is a short window during which the neonatal heart has the proliferative capacity to completely repair damage, an ability that is lost in adulthood. Inducing proliferation in adult cardiomyocytes by reactivating cell cycle reentry after myocardial infarction (MI) improves cardiac function. De novo purine synthesis is a critical source of nucleotides for cell proliferation. Here, using loss- and gain-of-function genetic approaches, we explored the role of the muscle-specific de novo purine synthesis enzyme Adssl1 in cardiac regeneration. Deletion of Adssl1 in mouse neonatal hearts reduced cardiomyocyte proliferation and attenuated heart regeneration after apical resection. Conversely, cardiomyocyte-specific Adssl1 overexpression extended the postnatal regenerative window and induced robust cell cycle reentry after MI, which decreased fibrotic scar size and improved cardiac function. RNA sequencing analysis suggested that Adssl1 overexpression induced strong dedifferentiation and cell cycle entry. Moreover, LC-MS/MS analysis showed that Adssl1 overexpression was associated with increased amounts of purine metabolites, including inosine, which is in clinical use. Administration of exogenous inosine promoted cardiac repair after MI in adult mice. At a molecular level, the increase in purine metabolite production mediated by Adssl1 enhanced the activity of the proliferation-promoting mTORC1 pathway. Our study identifies a role for Adssl1 in supporting cardiomyocyte proliferation and cardiac regeneration.

The global phosphorylation landscape of mouse oocytes during meiotic maturation

Phosphorylation is a key post-translational modification regulating protein function and biological outcomes. However, the phosphorylation dynamics orchestrating mammalian oocyte development remains poorly understood. In the present study, we apply high-resolution mass spectrometry-based phosphoproteomics to obtain the first global in vivo quantification of mouse oocyte phosphorylation. Of more than 8000 phosphosites, 75% significantly oscillate and 64% exhibit marked upregulation during meiotic maturation, indicative of the dominant regulatory role. Moreover, we identify numerous novel phosphosites on oocyte proteins and a few highly conserved phosphosites in oocytes from different species. Through functional perturbations, we demonstrate that phosphorylation status of specific sites participates in modulating critical events including metabolism, translation, and RNA processing during meiosis. Finally, we combine inhibitor screening and enzyme-substrate network prediction to discover previously unexplored kinases and phosphatases that are essential for oocyte maturation. In sum, our data define landscape of the oocyte phosphoproteome, enabling in-depth mechanistic insights into developmental control of germ cells.

Circular RNA IGF1R Promotes Cardiac Repair via Activating β-Catenin Signaling by Interacting with DDX5 in Mice after Ischemic Insults

The potential of circular RNAs (circRNAs) as biomarkers and therapeutic targets is becoming increasingly evident, yet their roles in cardiac regeneration and myocardial renewal remain largely unexplored. Here, we investigated the function of circIGF1R and related mechanisms in cardiac regeneration. Through analysis of circRNA sequencing data from neonatal and adult cardiomyocytes, circRNAs associated with regeneration were identified. Our data showed that circIGF1R expression was high in neonatal hearts, decreased with postnatal maturation, and up-regulated after cardiac injury. The elevation was validated in patients diagnosed with acute myocardial infarction (MI) within 1 week. In human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and myocardial tissue from mice after apical resection and MI, we observed that circIGF1R overexpression enhanced cardiomyocyte proliferation, reduced apoptosis, and mitigated cardiac dysfunction and fibrosis, while circIGF1R knockdown impeded endogenous cardiac renewal. Mechanistically, we identified circIGF1R binding proteins through circRNA precipitation followed by mass spectrometry. RNA pull-down Western blot and RNA immunoprecipitation demonstrated that circIGF1R directly interacted with DDX5 and augmented its protein level by suppressing ubiquitin-dependent degradation. This subsequently triggered the β-catenin signaling pathway, leading to the transcriptional activation of cyclin D1 and c-Myc. The roles of circIGF1R and DDX5 in cardiac regeneration were further substantiated through site-directed mutagenesis and rescue experiments. In conclusion, our study highlights the pivotal role of circIGF1R in facilitating heart regeneration and repair after ischemic insults. The circIGF1R/DDX5/β-catenin axis emerges as a novel therapeutic target for enhancing myocardial repair after MI, offering promising avenues for the development of regenerative therapies.

The role of serine/threonine protein kinases in cardiovascular disease and potential therapeutic methods

Protein phosphorylation is an important link in a variety of signaling pathways, and most of the important life processes in cells involve protein phosphorylation. Based on the amino acid residues of phosphorylated proteins, protein kinases can be categorized into the following families: serine/threonine protein kinases, tyrosine-specific protein kinases, histidine-specific protein kinases, tryptophan kinases, and aspartate/glutamyl protein kinases. Of all the protein kinases, most are serine/threonine kinases, where serine/threonine protein kinases are protein kinases that catalyze the phosphorylation of serine or threonine residues on target proteins using ATP as a phosphate donor. The current socially accepted classification of serine/threonine kinases is to divide them into seven major groups: protein kinase A, G, C (AGC), CMGC, Calmodulin-dependent protein kinase (CAMK), Casein kinase (CK1), STE, Tyrosine kinase (TKL) and others. After decades of research, a preliminary understanding of the specific classification and respective functions of serine/threonine kinases has entered a new period of exploration. In this paper, we review the literature of the previous years and introduce the specific signaling pathways and related therapeutic modalities played by each of the small protein kinases in the serine/threonine protein kinase family, respectively, in some common cardiovascular system diseases such as heart failure, myocardial infarction, ischemia-reperfusion injury, and diabetic cardiomyopathy. To a certain extent, the current research results, including molecular mechanisms and therapeutic methods, are fully summarized and a systematic report is made for the prevention and treatment of cardiovascular diseases in the future.

Quantitative Phosphoproteomic Profiling of Mouse Sperm Maturation in Epididymis Revealed Kinases Important for Sperm Motility

Transcriptionally and translationally silent sperm undergo functional maturation during epididymis traverse, which provides sperm ability to move and is crucial for successful fertilization. However, the molecular mechanisms governing sperm maturation remain poorly understood, especially at the protein post-translational modification level. In this study, we conducted a comprehensive quantitative phosphoproteomic analysis of mouse epididymal sperm from different regions (caput, corpus, and cauda) to unveil the dynamics of protein phosphorylation during sperm maturation. We identified 6447 phosphorylation sites in 1407 phosphoproteins, and 345 phosphoproteins were differentially phosphorylated between caput and cauda sperm. Gene ontology and KEGG pathway analyses showed enrichment of differentially phosphorylated proteins in energy metabolism, sperm motility, and fertilization. Kinase substrate network analysis followed by inhibition assay and quantitative phosphoproteomics analysis showed that TSSK2 kinase is important for sperm motility and progressive motility. This study systemically characterized the intricate phosphorylation regulation during sperm maturation in the mouse epididymis, which can be a basis to elucidate sperm motility acquisition, and to offer potential targets for male contraception and the treatment of male infertility.

Upregulation of LncRNA UCA1 promotes cardiomyocyte proliferation by inhibiting the miR-128/SUZ12/P27 pathway

Enhancing cardiomyocyte proliferation is essential to reverse or slow down the heart failure progression in many cardiovascular diseases such as myocardial infarction (MI). Long non-coding RNAs (lncRNAs) have been reported to regulate cardiomyocyte proliferation. In particular, lncRNA urothelial carcinoma-associated 1 (lncUCA1) played multiple roles in regulating cell cycle progression and cardiovascular diseases, making lncUCA1 a potential target for promoting cardiomyocyte proliferation. However, the role of lncUCA1 in cardiomyocyte proliferation remains unknown. This study aimed at exploring the function and underlying molecular mechanism of lncUCA1 in cardiomyocyte proliferation. Quantitative RT-PCR showed that lncUCA1 expression decreased in postnatal hearts. Gain-and-loss-of-function experiments showed that lncUCA1 positively regulated cardiomyocyte proliferation in vitro and in vivo. The bioinformatics program identified miR-128 as a potential target of lncUCA1, and loss of miR-128 was reported to promote cardiomyocyte proliferation by inhibiting the SUZ12/P27 pathway. Luciferase reporter assay, qRT-PCR, western blotting, and immunostaining experiments further revealed that lncUCA1 acted as a ceRNA of miR-128 to upregulate its target SUZ12 and downregulate P27, thereby increasing cyclin B1, cyclin E, CDK1 and CDK2 expression to promote cardiomyocyte proliferation. In conclusion, upregulation of lncRNA UCA1 promoted cardiomyocyte proliferation by inhibiting the miR-128/SUZ12/P27 pathway. Our results indicated that lncUCA1 might be a new therapeutic target for stimulating cardiomyocyte proliferation.

Checkpoint Kinase 1 Stimulates Endogenous Cardiomyocyte Renewal and Cardiac Repair by Binding to Pyruvate Kinase Isoform M2 C-Domain and Activating Cardiac Metabolic Reprogramming in a Porcine Model of Myocardial Ischemia/Reperfusion Injury

BACKGROUND

The regenerative capacity of the adult mammalian hearts is limited. Numerous studies have explored mechanisms of adult cardiomyocyte cell-cycle withdrawal. This translational study evaluated the effects and underlying mechanism of rhCHK1 (recombinant human checkpoint kinase 1) on the survival and proliferation of cardiomyocyte and myocardial repair after ischemia/reperfusion injury in swine.

METHODS AND RESULTS

Intramyocardial injection of rhCHK1 protein (1 mg/kg) encapsulated in hydrogel stimulated cardiomyocyte proliferation and reduced cardiac inflammation response at 3 days after ischemia/reperfusion injury, improved cardiac function and attenuated ventricular remodeling, and reduced the infarct area at 28 days after ischemia/reperfusion injury. Mechanistically, multiomics sequencing analysis demonstrated enrichment of glycolysis and mTOR (mammalian target of rapamycin) pathways after rhCHK1 treatment. Co-Immunoprecipitation (Co-IP) experiments and protein docking prediction showed that CHK1 (checkpoint kinase 1) directly bound to and activated the Serine 37 (S37) and Tyrosine 105 (Y105) sites of PKM2 (pyruvate kinase isoform M2) to promote metabolic reprogramming. We further constructed plasmids that knocked out different CHK1 and PKM2 amino acid domains and transfected them into Human Embryonic Kidney 293T (HEK293T) cells for CO-IP experiments. Results showed that the 1-265 domain of CHK1 directly binds to the 157-400 amino acids of PKM2. Furthermore, hiPSC-CM (human iPS cell-derived cardiomyocyte) in vitro and in vivo experiments both demonstrated that CHK1 stimulated cardiomyocytes renewal and cardiac repair by activating PKM2 C-domain-mediated cardiac metabolic reprogramming.

CONCLUSIONS

This study demonstrates that the 1-265 amino acid domain of CHK1 binds to the 157-400 domain of PKM2 and activates PKM2-mediated metabolic reprogramming to promote cardiomyocyte proliferation and myocardial repair after ischemia/reperfusion injury in adult pigs.

PEX3 promotes regenerative repair after myocardial injury in mice through facilitating plasma membrane localization of ITGB3

The peroxisome is a versatile organelle that performs diverse metabolic functions. PEX3, a critical regulator of the peroxisome, participates in various biological processes associated with the peroxisome. Whether PEX3 is involved in peroxisome-related redox homeostasis and myocardial regenerative repair remains elusive. We investigate that cardiomyocyte-specific PEX3 knockout (Pex3-KO) results in an imbalance of redox homeostasis and disrupts the endogenous proliferation/development at different times and spatial locations. Using Pex3-KO mice and myocardium-targeted intervention approaches, the effects of PEX3 on myocardial regenerative repair during both physiological and pathological stages are explored. Mechanistically, lipid metabolomics reveals that PEX3 promotes myocardial regenerative repair by affecting plasmalogen metabolism. Further, we find that PEX3-regulated plasmalogen activates the AKT/GSK3β signaling pathway via the plasma membrane localization of ITGB3. Our study indicates that PEX3 may represent a novel therapeutic target for myocardial regenerative repair following injury.

FOXA1 regulates ribosomal RNA transcription in prostate cancer

BACKGROUND

Ribosome biogenesis is excessively activated in tumor cells, yet it is little known whether oncogenic transcription factors (TFs) are involved in the ribosomal RNA (rRNA) transactivation.

METHODS

Nucleolar proteomics data and large-scale immunofluorescence were re-analyzed to jointly identify the proteins localized at nucleolus. RNA-Seq data of five prostate cancer (PCa) cohorts were combined and integrated with multi-dimensional data to define the upregulated nucleolar TFs in PCa tissues. Then, ChIP-Seq data of PCa cell lines and two PCa clinical cohorts were re-analyzed to reveal the TF binding patterns at ribosomal DNA (rDNA) repeats. The TF binding at rDNA was validated by ChIP-qPCR. The effect of the TF on rRNA transcription was determined by rDNA luciferase reporter, nascent RNA synthesis, and global protein translation assays.

RESULTS

In this study, we reveal the role of oncogenic TF FOXA1 in regulating rRNA transcription within nucleolar organization regions. By analyzing human TFs in prostate cancer clinical datasets and nucleolar proteomics data, we identified that FOXA1 is partially localized in the nucleolus and correlated with global protein translation. Our extensive FOXA1 ChIP-Seq analysis provides robust evidence of FOXA1 binding across rDNA repeats in prostate cancer cell lines, primary tumors, and castration-resistant variants. Notably, FOXA1 occupancy at rDNA repeats correlates with histone modifications associated with active transcription, namely H3K27ac and H3K4me3. Reducing FOXA1 expression results in decreased transactivation at rDNA, subsequently diminishing global protein synthesis.

CONCLUSIONS

Our results suggest FOXA1 regulates aberrant ribosome biogenesis downstream of oncogenic signaling in prostate cancer.

Tudor-SN promotes cardiomyocyte proliferation and neonatal heart regeneration through regulating the phosphorylation of YAP

BACKGROUND

The neonatal mammalian heart exhibits considerable regenerative potential following injury through cardiomyocyte proliferation, whereas mature cardiomyocytes withdraw from the cell cycle and lose regenerative capacities. Therefore, investigating the mechanisms underlying neonatal cardiomyocyte proliferation and regeneration is crucial for unlocking the regenerative potential of adult mammalian heart to repair damage and restore contractile function following myocardial injury.

METHODS

The Tudor staphylococcal nuclease (Tudor-SN) transgenic (TG) or cardiomyocyte-specific knockout mice (Myh6-Tudor-SN -/-) were generated to investigate the role of Tudor-SN in cardiomyocyte proliferation and heart regeneration following apical resection (AR) surgery. Primary cardiomyocytes isolated from neonatal mice were used to assess the influence of Tudor-SN on cardiomyocyte proliferation in vitro. Affinity purification and mass spectrometry were employed to elucidate the underlying mechanism. H9c2 cells and mouse myocardia with either overexpression or knockout of Tudor-SN were utilized to assess its impact on the phosphorylation of Yes-associated protein (YAP), both in vitro and in vivo.

RESULTS

We previously identified Tudor-SN as a cell cycle regulator that is highly expressed in neonatal mice myocardia but downregulated in adults. Our present study demonstrates that sustained expression of Tudor-SN promotes and prolongs the proliferation of neonatal cardiomyocytes, improves cardiac function, and enhances the ability to repair the left ventricular apex resection in neonatal mice. Consistently, cardiomyocyte-specific knockout of Tudor-SN impairs cardiac function and retards recovery after injury. Tudor-SN associates with YAP, which plays important roles in heart development and regeneration, inhibiting phosphorylation at Ser 127 and Ser 397 residues by preventing the association between Large Tumor Suppressor 1 (LATS1) and YAP, correspondingly maintaining stability and promoting nuclear translocation of YAP to enhance the proliferation-related genes transcription.

CONCLUSION

Tudor-SN regulates the phosphorylation of YAP, consequently enhancing and prolonging neonatal cardiomyocyte proliferation under physiological conditions and promoting neonatal heart regeneration after injury.

E3 Ubiquitin Ligase ASB14 Inhibits Cardiomyocyte Proliferation by Regulating MAPRE2 Ubiquitination

The ubiquitin proteasome system is a highly specific and selective protein regulatory system that plays an essential role in the regulation of the cell cycle. Despite its significance, the role of ubiquitination in cardiomyocyte proliferation remains largely unclear. This study aimed to investigate the potential impact of E3 ubiquitin ligase ASB14 (Ankyrin Repeat And SOCS Box Containing 14) on cardiac regeneration. We conducted a microarray analysis of apical resection ventricle tissues, and our findings revealed that ASB14 was down-regulated during the cardiac regenerative response. Subsequently, we examined the effect of ASB14 silencing on cardiomyocyte nuclear proliferation both in vitro and in vivo. Our results indicated that ASB14 silencing promoted cardiomyocyte nuclear proliferation, suggesting that ASB14 may play a role in regulating cardiac regeneration. To further investigate the potential therapeutic implications of ASB14 deficiency, we examined the cardiac function of mice with ASB14 deficiency in response to ischemic injury. Our findings showed that mice with ASB14 deficiency exhibited preserved cardiac function and a therapeutic effect in response to ischemic injury, which was attributed to the enhancement of cardiomyocyte nuclear proliferation. To elucidate the underlying mechanisms, we investigated the effect of ASB14 on microtubule-associated protein RP/EB family member 2 (MAPRE2) protein degradation. Our results indicated that the loss of ASB14 decreased the degradation of MAPRE2 protein, subsequently promoting cardiomyocyte nuclear proliferation and enhancing cardiac repair after myocardial infarction (MI). In conclusion, our study provides evidence that inhibition of ASB14-mediated MAPRE2 ubiquitination promotes cardiomyocyte nuclear proliferation, which may serve as a potential target for treating heart failure induced by MI injury.

Ribosomal Dysregulation in Metastatic Laryngeal Squamous Cell Carcinoma: Proteomic Insights and CX-5461's Therapeutic Promise

One of the main barriers to the successful treatment of laryngeal squamous cell carcinoma (LSCC) is postoperative progression, primarily due to tumor cell metastasis. To systematically investigate the molecular characteristics and potential mechanisms underlying the metastasis in laryngeal cancer, we carried out a TMT-based proteomic analysis of both cancerous and adjacent non-cancerous tissues from 10 LSCC patients with lymph node metastasis (LNM) and 10 without. A total of 5545 proteins were quantified across all samples. We identified 57 proteins that were downregulated in LSCC with LNM, which were enriched in cell adhesion pathways, and 69 upregulated proteins predominantly enriched in protein production pathways. Importantly, our data revealed a strong correlation between increased ribosomal activity and the presence of LNM, as 18 ribosomal subunit proteins were found to be upregulated, with RPS10 and RPL24 being the most significantly overexpressed. The potential of ribosomal proteins, including RPS10 and RPL24, as biomarkers for LSCC with LNM was confirmed in external validation samples (six with LNM and six without LNM) using Western blotting and immunohistochemistry. Furthermore, we have confirmed that the RNA polymerase I inhibitor CX-5461, which impedes ribosome biogenesis in LSCC, also decreases the expression of RPS10, RPL24, and RPS26. In vitro experiments have revealed that CX-5461 moderately reduces cell viability, while it significantly inhibits the invasion and migration of LSCC cells. It can enhance the expression of the epithelial marker CDH1 and suppress the expression of the mesenchymal markers CDH2, VIM, and FN at a dose that does not affect cell viability. Our study broadens the scope of the proteomic data on laryngeal cancer and suggests that ribosome targeting could be a supplementary therapeutic strategy for metastatic LSCC.

Cellular nucleic acid binding protein facilitates cardiac repair after myocardial infarction by activating β-catenin signaling

The regenerative capacity of the adult mammalian heart is limited, while the neonatal heart is an organ with regenerative and proliferative ability. Activating adult cardiomyocytes (CMs) to re-enter the cell cycle is an effective therapeutic method for ischemic heart disease such as myocardial infarction (MI) and heart failure. Here, we aimed to reveal the role and potential mechanisms of cellular nucleic acid binding protein (CNBP) in cardiac regeneration and repair after heart injury. CNBP is highly expressed within 7 days post-birth while decreases significantly with the loss of regenerative ability. In vitro, overexpression of CNBP promoted CM proliferation and survival, whereas knockdown of CNBP inhibited these processes. In vivo, knockdown of CNBP in CMs robustly hindered myocardial regeneration after apical resection in neonatal mice. In adult MI mice, CM-specific CNBP overexpression in the infarct border zone ameliorated myocardial injury in acute stage and facilitated CM proliferation and functional recovery in the long term. Quantitative proteomic analysis with TMT labeling showed that CNBP overexpression promoted the DNA replication, cell cycle progression, and cell division. Mechanically, CNBP overexpression increased the expression of β-catenin and its downstream target genes CCND1 and c-myc; Furthermore, Luciferase reporter and Chromatin immunoprecipitation (ChIP) assays showed that CNBP could directly bind to the β-catenin promoter and promote its transcription. CNBP also upregulated the expression of G1/S-related cell cycle genes CCNE1, CDK2, and CDK4. Collectively, our study reveals the positive role of CNBP in promoting cardiac repair after injury, providing a new therapeutic option for the treatment of MI.

Versican Promotes Cardiomyocyte Proliferation and Cardiac Repair

BACKGROUND

The adult mammalian heart is incapable of regeneration, whereas a transient regenerative capacity is maintained in the neonatal heart, primarily through the proliferation of preexisting cardiomyocytes. Neonatal heart regeneration after myocardial injury is accompanied by an expansion of cardiac fibroblasts and compositional changes in the extracellular matrix. Whether and how these changes influence cardiomyocyte proliferation and heart regeneration remains to be investigated.

METHODS

We used apical resection and myocardial infarction surgical models in neonatal and adult mice to investigate extracellular matrix components involved in heart regeneration after injury. Single-cell RNA sequencing and liquid chromatography-mass spectrometry analyses were used for versican identification. Cardiac fibroblast-specific Vcan deletion was achieved using the mouse strains Col1a2-2A-CreER and Vcanfl/fl. Molecular signaling pathways related to the effects of versican were assessed through Western blot, immunostaining, and quantitative reverse transcription polymerase chain reaction. Cardiac fibrosis and heart function were evaluated by Masson trichrome staining and echocardiography, respectively.

RESULTS

Versican, a cardiac fibroblast-derived extracellular matrix component, was upregulated after neonatal myocardial injury and promoted cardiomyocyte proliferation. Conditional knockout of Vcan in cardiac fibroblasts decreased cardiomyocyte proliferation and impaired neonatal heart regeneration. In adult mice, intramyocardial injection of versican after myocardial infarction enhanced cardiomyocyte proliferation, reduced fibrosis, and improved cardiac function. Furthermore, versican augmented the proliferation of human induced pluripotent stem cell-derived cardiomyocytes. Mechanistically, versican activated integrin β1 and downstream signaling molecules, including ERK1/2 and Akt, thereby promoting cardiomyocyte proliferation and cardiac repair.

CONCLUSIONS

Our study identifies versican as a cardiac fibroblast-derived pro-proliferative proteoglycan and clarifies the role of versican in promoting adult cardiac repair. These findings highlight its potential as a therapeutic factor for ischemic heart diseases.

N-Acetyltransferase 10 represses Uqcr11 and Uqcrb independently of ac4C modification to promote heart regeneration

Translational control is crucial for protein production in various biological contexts. Here, we use Ribo-seq and RNA-seq to show that genes related to oxidative phosphorylation are translationally downregulated during heart regeneration. We find that Nat10 regulates the expression of Uqcr11 and Uqcrb mRNAs in mouse and human cardiomyocytes. In mice, overexpression of Nat10 in cardiomyocytes promotes cardiac regeneration and improves cardiac function after injury. Conversely, treating neonatal mice with Remodelin-a Nat10 pharmacological inhibitor-or genetically removing Nat10 from their cardiomyocytes both inhibit heart regeneration. Mechanistically, Nat10 suppresses the expression of Uqcr11 and Uqcrb independently of its ac4C enzyme activity. This suppression weakens mitochondrial respiration and enhances the glycolytic capacity of the cardiomyocytes, leading to metabolic reprogramming. We also observe that the expression of Nat10 is downregulated in the cardiomyocytes of P7 male pig hearts compared to P1 controls. The levels of Nat10 are also lower in female human failing hearts than non-failing hearts. We further identify the specific binding regions of Nat10, and validate the pro-proliferative effects of Nat10 in cardiomyocytes derived from human embryonic stem cells. Our findings indicate that Nat10 is an epigenetic regulator during heart regeneration and could potentially become a clinical target.

Cardiac regeneration: Pre-existing cardiomyocyte as the hub of novel signaling pathway

In the mammalian heart, cardiomyocytes are forced to withdraw from the cell cycle shortly after birth, limiting the ability of the heart to regenerate and repair. The development of multimodal regulation of cardiac proliferation has verified that pre-existing cardiomyocyte proliferation is an essential driver of cardiac renewal. With the continuous development of genetic lineage tracking technology, it has been revealed that cell cycle activity produces polyploid cardiomyocytes during the embryonic, juvenile, and adult stages of cardiogenesis, but newly formed mononucleated diploid cardiomyocytes also elevated sporadically during myocardial infarction. It implied that adult cardiomyocytes have a weak regenerative capacity under the condition of ischemia injury, which offers hope for the clinical treatment of myocardial infarction. However, the regeneration frequency and source of cardiomyocytes are still low, and the mechanism of regulating cardiomyocyte proliferation remains further explained. It is noteworthy to explore what force triggers endogenous cardiomyocyte proliferation and heart regeneration. Here, we focused on summarizing the recent research progress of emerging endogenous key modulators and crosstalk with other signaling pathways and furnished valuable insights into the internal mechanism of heart regeneration. In addition, myocardial transcription factors, non-coding RNAs, cyclins, and cell cycle-dependent kinases are involved in the multimodal regulation of pre-existing cardiomyocyte proliferation. Ultimately, awakening the myocardial proliferation endogenous modulator and regeneration pathways may be the final battlefield for the regenerative therapy of cardiovascular diseases.

Activation of AHR by ITE improves cardiac remodelling and function in rats after myocardial infarction

AIMS

Left ventricular remodelling subsequent to myocardial infarction (MI) constitutes a pivotal underlying cause of heart failure. Intervention with the nontoxic endogenous aryl hydrocarbon receptor (AHR) agonist 2-(1'H-indole-3'-carbonyl)-thiazole-4-carboxylic acid methyl ester (ITE) in the acute phase of MI has been shown to ameliorate cardiac function, but its role in the chronic phase remains obscured. This study explores the beneficial role of ITE in delaying the progression of heart failure in the chronic phase of MI.

METHODS AND RESULTS

MI rats established by ligating the left anterior descending coronary artery were treated with the indicated concentration of the AHR agonist ITE or vehicle alone. Echocardiography was performed to determine cardiac structure and function; myocardial morphology and fibrosis were observed by haematoxylin and eosin and Masson's trichrome staining; serum biochemical indices, BNP, and inflammatory cytokine levels were detected by enzyme-linked immunosorbent assay; F4/80+ iNOS+ M1 macrophages and F4/80+ CD206+ M2 macrophages were detected by immunofluorescence; the terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling assay was used to detect the apoptosis of cardiomyocytes; ultrastructural changes in myocardial tissue were observed by transmission electron microscopy; and Cyp1a1, Akt, P-Akt, p70S6K, P-p70S6K, Bcl-2, Bax, caspase-3, and cleaved caspase-3 protein levels were determined via Western blotting. We found that therapy with the AHR agonist ITE rescued cardiac remodelling and dysfunction in rats with MI and attenuated myocardial fibrosis, inflammation, and mitochondrial damage. Further studies confirmed that ITE dose-dependently improved myocardial cell apoptosis after MI, as demonstrated by reduced levels of the apoptosis-related proteins cleaved caspase-3 and Bax but increased expression levels of Bcl-2. These effects were attributed to ITE-induced activation of AHR receptors, leading to the down-regulation of Akt and p70S6K phosphorylation.

CONCLUSIONS

The AHR agonist ITE alleviates cardiomyocyte apoptosis through the Akt/p70S6K signalling pathway, thereby rescuing left ventricular adverse remodelling and cardiac dysfunction after MI.

Protein Kinases and their Inhibitors Implications in Modulating Disease Progression

Protein phosphorylation plays an important role in cellular pathways, including cell cycle regulation, metabolism, differentiation and survival. The protein kinase superfamily network consists of 518 members involved in intrinsic or extrinsic interaction processes. Protein kinases are divided into two categories based on their ability to phosphorylate tyrosine, serine, and threonine residues. The complexity of the system implies its vulnerability. Any changes in the pathways of protein kinases may be implicated in pathological processes. Therefore, they are regarded as having an important role in human diseases and represent prospective therapeutic targets. This article provides a review of the protein kinase inhibitors approved by the FDA. Finally, we summarize the mechanism of action of protein kinases, including their role in the development and progression of protein kinase-related roles in various pathological conditions and the future therapeutic potential of protein kinase inhibitors, along with links to protein kinase databases. Further clinical studies aimed at examining the sequence of protein kinase inhibitor availability would better utilize current protein kinase inhibitors in diseases. Additionally, this review may help researchers and biochemists find new potent and selective protein kinase inhibitors and provide more indications for using existing drugs.

SIRT3-dependent mitochondrial redox homeostasis mitigates CHK1 inhibition combined with gemcitabine treatment induced cardiotoxicity in hiPSC-CMs and mice

Administration of CHK1-targeted anticancer therapies is associated with an increased cumulative risk of cardiac complications, which is further amplified when combined with gemcitabine. However, the underlying mechanisms remain elusive. In this study, we generated hiPSC-CMs and murine models to elucidate the mechanisms underlying CHK1 inhibition combined with gemcitabine-induced cardiotoxicity and identify potential targets for cardioprotection. Mice were intraperitoneally injected with 25 mg/kg CHK1 inhibitor AZD7762 and 20 mg/kg gemcitabine for 3 weeks. hiPSC-CMs and NMCMs were incubated with 0.5 uM AZD7762 and 0.1 uM gemcitabine for 24 h. Both pharmacological inhibition or genetic deletion of CHK1 and administration of gemcitabine induced mtROS overproduction and pyroptosis in cardiomyocytes by disrupting mitochondrial respiration, ultimately causing heart atrophy and cardiac dysfunction in mice. These toxic effects were further exacerbated with combination administration. Using mitochondria-targeting sequence-directed vectors to overexpress CHK1 in cardiomyocyte (CM) mitochondria, we identified the localization of CHK1 in CM mitochondria and its crucial role in maintaining mitochondrial redox homeostasis for the first time. Mitochondrial CHK1 function loss mediated the cardiotoxicity induced by AZD7762 and CHK1-knockout. Mechanistically, mitochondrial CHK1 directly phosphorylates SIRT3 and promotes its expression within mitochondria. On the contrary, both AZD7762 or CHK1-knockout and gemcitabine decreased mitochondrial SIRT3 abundance, thus resulting in respiration dysfunction. Further hiPSC-CMs and mice experiments demonstrated that SIRT3 overexpression maintained mitochondrial function while alleviating CM pyroptosis, and thereby improving mice cardiac function. In summary, our results suggest that targeting SIRT3 could represent a novel therapeutic approach for clinical prevention and treatment of cardiotoxicity induced by CHK1 inhibition and gemcitabine.

Ammonium Persulfate-Loaded Carboxylic Gelatin-Methacrylate Nanoparticles Promote Cardiac Repair by Activating Epicardial Epithelial-Mesenchymal Transition via Autophagy and the mTOR Pathway

Restoring damaged myocardial tissue with therapeutic exogenous cells still has some limitations, such as immunological rejection, immature cardiac properties, risk of tumorigenicity, and a low cell survival rate in the ischemic myocardium microenvironment. Activating the endogenous stem cells with functional biomaterials might overcome these limitations. Research has highlighted the multiple differentiation potential of epicardial cells via epithelial-mesenchymal transition (EMT) in both heart development and cardiac regeneration. In our previous research, a carboxylic gelatin-methacrylate (carbox-GelMA) nanoparticle (NP) was fabricated to carry ammonium persulfate (APS), and APS-loaded carbox-GelMA NPs (NPs/APS) could drive the EMT of MCF-7 cells in vitro and promote cancer cell migration and invasion in vivo. The present study explored the roles of functional NPs/APS in the EMT of Wilms' tumor 1-positive (WT1+) epicardial cells and in the repair of myocardial infarction (MI). The WT1+ epicardial cells transformed into endothelial-like cells after being treated with NPs/APS in vitro, and the cardiac functions were improved significantly after injecting NPs/APS into the infarcted hearts in vivo. Furthermore, simultaneous activation of both autophagy and the mTOR pathway was confirmed during the NPs/APS-induced EMT process in WT1+ epicardial cells. Together, this study highlights the function of NPs/APS in the repair of MI.

Proteomic analysis of neonatal mouse hearts shows PKA functions as a cardiomyocyte replication regulator

The ability of the adult mammalian heart to regenerate can save the cardiac muscle from a loss of function caused by injury. Cardiomyocyte regeneration is a key aspect of research for the treatment of cardiovascular diseases. The mouse heart shows temporary regeneration in the first week after birth; thus, the newborn mouse heart is an ideal model to study heart muscle regeneration. In this study, proteomic analysis was used to investigate the differences in protein expression in the hearts of neonatal mice at days 1 (P1 group), 4 (P4 group), and 7 (P7 group). Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed changes in several groups of proteins, including the protein kinase A (PKA) signaling pathway. Moreover, it was found that PKA inhibitors and agonists regulated cardiomyocyte replication in neonatal mouse hearts. These findings suggest that PKA may be a target for the regulation of the cardiomyocyte cell cycle.

Deubiquitinase JOSD2 improves calcium handling and attenuates cardiac hypertrophy and dysfunction by stabilizing SERCA2a in cardiomyocytes

Cardiac hypertrophy leads to myocardial dysfunction and represents a serious threat to global public health security. Deubiquitinating enzymes (DUBs) mainly maintain the stability of substrate proteins and are essential to cardiac pathophysiology. Here, we explored the role and regulating mechanism of a DUB, Josephin domain-containing protein 2 (JOSD2), in cardiac hypertrophy. We found that JOSD2 expression was significantly upregulated in hypertrophic myocardium. Josd2 gene knockout aggravated cardiac dysfunction and hypertrophy in mice, whereas cardiac overexpression of JOSD2 mediated by the AAV9 vector prevented angiotensin II-induced cardiac hypertrophy. A comprehensive proteome-wide quantitative analysis identified sarco/endoplasmic reticulum calcium ATPase 2a (SERCA2a) as a key substrate of JOSD2. Mechanistically, JOSD2 mediates SERCA2a deubiquitination, enhancing the stability of SERCA2a. By regulating SERCA2a, JOSD2 deficiency impairs calcium handling and promotes hypertrophy in primary cardiomyocytes. Our findings highlight the promise of JOSD2 as a beneficial therapeutic target for hypertrophic cardiomyopathy and provide an additional strategy for SERCA2a-targeted therapy.

A modified apical resection model with high accuracy and reproducibility in neonatal mouse and rat hearts

Neonatal mouse heart can regenerate after left ventricle (LV) apical resection (AR). Since current AR rodent method is accomplished by resecting LV apex until exposure of LV chamber, it is relatively difficult to operate reproducibly. We aimed to develop a modified AR method with high accuracy and reproducibility and to investigate whether cardiac regenerative capacity could be replicated in neonatal rats. For 15% AR of whole heart weight in 1-day-old (P1) neonatal mice, a modified 10 μL pipette tip cut to 0.48 mm in internal diameter was connected to a vacuum pump working at 0.06 ± 0.005 MPa and gently kept in touch with LV apex for nearly but no more than 12 s. LV apex was resected by a single incision adjacent to the pipette tip. The modified AR method in P1 mice achieved cardiac structural and functional recovery at 21 days post resection (dpr). Data from different operators showed smaller variation of resected LV apex and higher reproducibility using the modified AR method. Furthermore, we showed that 5% AR of whole heart weight in P1 neonatal rats using a modified 200 μL pipette tip cut to 0.63 mm in internal diameter led to complete regeneration of LV apex and full preservation of cardiac function at 42 dpr. In conclusion, the modified AR rodent model leads to accurate resection of LV apex with high homogeneity and reproducibility and it is practically convenient for the study of structural, functional, and molecular mechanisms of cardiac regeneration in both neonatal mice and rats.

Absence of CEP78 causes photoreceptor and sperm flagella impairments in mice and a human individual

Cone-rod dystrophy (CRD) is a genetically inherited retinal disease that can be associated with male infertility, while the specific genetic mechanisms are not well known. Here, we report CEP78 as a causative gene of a particular syndrome including CRD and male infertility with multiple morphological abnormalities of sperm flagella (MMAF) both in human and mouse. Cep78 knockout mice exhibited impaired function and morphology of photoreceptors, typified by reduced ERG amplitudes, disrupted translocation of cone arrestin, attenuated and disorganized photoreceptor outer segments (OS) disks and widen OS bases, as well as interrupted connecting cilia elongation and abnormal structures. Cep78 deletion also caused male infertility and MMAF, with disordered '9+2' structure and triplet microtubules in sperm flagella. Intraflagellar transport (IFT) proteins IFT20 and TTC21A are identified as interacting proteins of CEP78. Furthermore, CEP78 regulated the interaction, stability, and centriolar localization of its interacting protein. Insufficiency of CEP78 or its interacting protein causes abnormal centriole elongation and cilia shortening. Absence of CEP78 protein in human caused similar phenotypes in vision and MMAF as Cep78^-/- mice. Collectively, our study supports the important roles of CEP78 defects in centriole and ciliary dysfunctions and molecular pathogenesis of such multi-system syndrome.

Ribosome biogenesis in disease: new players and therapeutic targets

The ribosome is a multi-unit complex that translates mRNA into protein. Ribosome biogenesis is the process that generates ribosomes and plays an essential role in cell proliferation, differentiation, apoptosis, development, and transformation. The mTORC1, Myc, and noncoding RNA signaling pathways are the primary mediators that work jointly with RNA polymerases and ribosome proteins to control ribosome biogenesis and protein synthesis. Activation of mTORC1 is required for normal fetal growth and development and tissue regeneration after birth. Myc is implicated in cancer development by enhancing RNA Pol II activity, leading to uncontrolled cancer cell growth. The deregulation of noncoding RNAs such as microRNAs, long noncoding RNAs, and circular RNAs is involved in developing blood, neurodegenerative diseases, and atherosclerosis. We review the similarities and differences between eukaryotic and bacterial ribosomes and the molecular mechanism of ribosome-targeting antibiotics and bacterial resistance. We also review the most recent findings of ribosome dysfunction in COVID-19 and other conditions and discuss the consequences of ribosome frameshifting, ribosome-stalling, and ribosome-collision. We summarize the role of ribosome biogenesis in the development of various diseases. Furthermore, we review the current clinical trials, prospective vaccines for COVID-19, and therapies targeting ribosome biogenesis in cancer, cardiovascular disease, aging, and neurodegenerative disease.

Phosphoproteomics Profile of Chicken Cecum in the Response to Salmonella enterica Serovar Enteritidis Inoculation

Salmonella enterica serovar Enteritidis (S. Enteritidis) is a foodborne pathogen, which can cause great threats to human health through the consumption of contaminated poultry products. This research combines TMT labeling, HPLC and mass-spectrometry-based phosphoproteomics on cecum of the F1 cross of Guangxi Yao chicken and Jining Bairi chicken. The treated group was inoculated with 0.3 mL inoculum S. Enteritidis, and the control group was inoculated with 0.3 mL phosphate-buffered saline (PBS). A total of 338 differentially phosphorylated modification sites in 243 differentially phosphorylated proteins (DPPs) were chosen for downstream analyses. A total of 213 sites in 146 DPPs were up-regulated and 125 sites in 97 DPPs were down-regulated. Functional analysis was performed for DPPs based on gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and the protein domain. The DPPs were mainly enriched in immune- and metabolic-related GO-BP (biological process) and KEGG pathways. We predicted and classified the subcellular structure and COG/KOG of DPPs. Furthermore, protein-protein interaction network analyses were performed by using multiple algorithms. We identified 71 motifs of the phosphorylated modification sites and selected 18 sites randomly to detect the expression level through parallel reaction monitoring (PRM). S. Enteritidis inoculation caused phosphorylation alteration in immune- and metabolic-related proteins. The invasion of S. Enteritidis may be actualized by inducing cecum cell apoptosis through the endoplasmic reticulum pathway, and chickens could resist the invasion of S. Enteritidis by affecting the function of ECM receptors. The findings herein provide a crucial theoretical foundation to understand the molecular mechanism and epigenetic regulation in response to S. Enteritidis inoculation in chickens.

A male germ-cell-specific ribosome controls male fertility

Ribosomes are highly sophisticated translation machines that have been demonstrated to be heterogeneous in the regulation of protein synthesis^1,2. Male germ cell development involves complex translational regulation during sperm formation³. However, it remains unclear whether translation during sperm formation is performed by a specific ribosome. Here we report a ribosome with a specialized nascent polypeptide exit tunnel, Ribosome^ST, that is assembled with the male germ-cell-specific protein RPL39L, the paralogue of core ribosome (Ribosome^Core) protein RPL39. Deletion of Ribosome^ST in mice causes defective sperm formation, resulting in substantially reduced fertility. Our comparison of single-particle cryo-electron microscopy structures of ribosomes from mouse kidneys and testes indicates that Ribosome^ST features a ribosomal polypeptide exit tunnel of distinct size and charge states compared with Ribosome^Core. Ribosome^ST predominantly cotranslationally regulates the folding of a subset of male germ-cell-specific proteins that are essential for the formation of sperm. Moreover, we found that specialized functions of Ribosome^ST were not replaceable by Ribosome^Core. Taken together, identification of this sperm-specific ribosome should greatly expand our understanding of ribosome function and tissue-specific regulation of protein expression pattern in mammals.

CDK9 binds and activates SGK3 to promote cardiac repair after injury via the GSK-3β/β-catenin pathway

The mammalian heart possesses entire regeneration capacity after birth, which is lost in adulthood. The role of the kinase network in myocardial regeneration remains largely elusive. SGK3 (threonine-protein kinase 3) is a functional kinase we identified previously with the capacity to promote cardiomyocyte proliferation and cardiac repair after myocardial infarction. However, the upstream signals regulating SGK3 are still unknown. Based on the quantitative phosphoproteomics data and pulldown assay, we identified cyclin-dependent kinase 9 (CDK9) as a novel therapeutic target in regeneration therapy. The direct combination between CDK9 and SGK3 was further confirmed by co-immunoprecipitation (Co-IP). CDK9 is highly expressed in the newborn period and rarely detected in the adult myocardium. In vitro, the proliferation ratio of primary cardiomyocytes was significantly elevated by CDK9 overexpression while inhibited by CDK9 knockdown. In vivo, inhibition of CDK9 shortened the time window of cardiac regeneration after apical resection (AR) in neonatal mice, while overexpression of CDK9 significantly promoted mature cardiomyocytes (CMs) to re-enter the cell cycle and cardiac repair after myocardial infarction (MI) in adult mice. Mechanistically, CDK9 promoted cardiac repair by directly activating SGK3 and downstream GSK-3β/β-catenin pathway. Consequently, our study indicated that CDK9 might be a novel target for MI therapy by stimulating myocardial regeneration.

Global phosphoproteomic analysis identified key kinases regulating male meiosis in mouse

Meiosis, a highly conserved process in organisms from fungi to mammals, is subjected to protein phosphorylation regulation. Due to the low abundance of phosphorylation, there is a lack of systemic characterization of phosphorylation regulation of meiosis in mammals. Using the phosphoproteomic approach, we profiled large-scale phosphoproteome of purified primary spermatocytes undergoing meiosis I, and identified 14,660 phosphorylation sites in 4419 phosphoproteins. Kinase-substrate phosphorylation network analysis followed by in vitro meiosis study showed that CDK9 was essential for meiosis progression to metaphase I and had enriched substrate phosphorylation sites in proteins involved in meiotic cell cycle. In addition, histones and epigenetic factors were found to be widely phosphorylated. Among those, HASPIN was found to be essential for male fertility. Haspin knockout led to misalignment of chromosomes, apoptosis of metaphase spermatocytes and a decreased number of sperm by deregulation of H3T3ph, chromosomal passenger complex (CPC) and spindle assembly checkpoint (SAC). The complicated protein phosphorylation and its important regulatory functions in meiosis indicated that in-depth studies of phosphorylation-mediated signaling could help us elucidate the mechanisms of meiosis.

The RalGAPα1-RalA signal module protects cardiac function through regulating calcium homeostasis

Sarcoplasmic/endoplasmic reticulum calcium ATPase SERCA2 mediates calcium re-uptake from the cytosol into sarcoplasmic reticulum, and its dysfunction is a hallmark of heart failure. Multiple factors have been identified to modulate SERCA2 activity, however, its regulation is still not fully understood. Here we identify a Ral-GTPase activating protein RalGAPα1 as a critical regulator of SERCA2 in cardiomyocytes through its downstream target RalA. RalGAPα1 is induced by pressure overload, and its deficiency causes cardiac dysfunction and exacerbates pressure overload-induced heart failure. Mechanistically, RalGAPα1 regulates SERCA2 through direct interaction and its target RalA. Deletion of RalGAPα1 decreases SERCA2 activity and prolongs calcium re-uptake into sarcoplasmic reticulum. GDP-bound RalA, but not GTP-bound RalA, binds to SERCA2 and activates the pump for sarcoplasmic reticulum calcium re-uptake. Overexpression of a GDP-bound RalAS28N mutant in the heart preserves cardiac function in a mouse model of heart failure. Our findings have therapeutic implications for treatment of heart failure.

SARS-CoV-2 ORF10 impairs cilia by enhancing CUL2ZYG11B activity

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causal pathogen of the ongoing global pandemic of coronavirus disease 2019 (COVID-19). Loss of smell and taste are symptoms of COVID-19, and may be related to cilia dysfunction. Here, we found that the SARS-CoV-2 ORF10 increases the overall E3 ligase activity of the CUL2^ZYG11B complex by interacting with ZYG11B. Enhanced CUL2^ZYG11B activity by ORF10 causes increased ubiquitination and subsequent proteasome-mediated degradation of an intraflagellar transport (IFT) complex B protein, IFT46, thereby impairing both cilia biogenesis and maintenance. Further, we show that exposure of the respiratory tract of hACE2 mice to SARS-CoV-2 or SARS-CoV-2 ORF10 alone results in cilia-dysfunction-related phenotypes, and the ORF10 expression in primary human nasal epithelial cells (HNECs) also caused a rapid loss of the ciliary layer. Our study demonstrates how SARS-CoV-2 ORF10 hijacks CUL2^ZYG11B to eliminate IFT46 and leads to cilia dysfunction, thereby offering a powerful etiopathological explanation for how SARS-CoV-2 causes multiple cilia-dysfunction-related symptoms specific to COVID-19.

Ad hoc learning of peptide fragmentation from mass spectra enables an interpretable detection of phosphorylated and cross-linked peptides

Mass spectrometry-based proteomics provides a holistic snapshot of the entire protein set of living cells on a molecular level. Currently, only a few deep learning approaches exist that involve peptide fragmentation spectra, which represent partial sequence information of proteins. Commonly, these approaches lack the ability to characterize less studied or even unknown patterns in spectra because of their use of explicit domain knowledge. Here, to elevate unrestricted learning from spectra, we introduce ‘ad hoc learning of fragmentation’ (AHLF), a deep learning model that is end-to-end trained on 19.2 million spectra from several phosphoproteomic datasets. AHLF is interpretable, and we show that peak-level feature importance values and pairwise interactions between peaks are in line with corresponding peptide fragments. We demonstrate our approach by detecting post-translational modifications, specifically protein phosphorylation based on only the fragmentation spectrum without a database search. AHLF increases the area under the receiver operating characteristic curve (AUC) by an average of 9.4% on recent phosphoproteomic data compared with the current state of the art on this task. Furthermore, use of AHLF in rescoring search results increases the number of phosphopeptide identifications by a margin of up to 15.1% at a constant false discovery rate. To show the broad applicability of AHLF, we use transfer learning to also detect cross-linked peptides, as used in protein structure analysis, with an AUC of up to 94%.

P16ink4a overexpression ameliorates cardiac remodeling of mouse following myocardial infarction via CDK4/pRb pathway

BACKGROUND

P16ink4a can accumulate in senescent cells and can be induced by different oncogenic stimulations. These functions make p16ink4a a biomarker of senescence and cancer. However, the exact role of p16ink4a remains unclear in cardiovascular disease. This study was aimed to investigate the role of p16ink4a in cardiac remodeling after myocardial infarction (MI).

METHODS

In vivo, gain and loss of function experiments using p16ink4a overexpression and knockdown adenovirus were induced to determine the effect of p16ink4a on cardiac structure and function after MI. The in vitro effects of p16ink4a were evaluated by overexpression and knockdown adenovirus of p16ink4a on isolated neonatal mouse cardiac myocytes (NMCMs) and neonatal mouse cardiac fibroblasts (NMCFs).

RESULTS

Expression level of p16ink4a was increased after MI and enriched in the infarction area. In vivo, overexpression of p16ink4a protected, while knockdown of p16ink4a worsened cardiac function. In vitro, p16ink4a did not influence the hypertrophy of NMCMs. Overexpression of p16ink4a inhibited the proliferation and migration of NMCFs and reduced the level of collagen I and α-SMA. Consistently, knockdown of p16ink4a in vitro displayed the opposite effects. Further mechanism studies revealed that p16ink4a affected the expression level of cyclin-dependent kinase 4 (CDK4) and phosphorylation of retinoblastoma (pRb), which could be a potential pathway in regulating cardiac remodeling after MI.

CONCLUSION

Overexpression of 16ink4a in cardiac fibroblasts can ameliorate cardiac dysfunction and attenuate pathological cardiac remodeling in mice after MI by regulating the p16ink4a/CDK4/pRb pathway.

m6A hypomethylation of DNMT3B regulated by ALKBH5 promotes intervertebral disc degeneration via E4F1 deficiency

BACKGROUND

The intervertebral disc (IVD) degeneration is the leading cause of low back pain, which accounts for a main cause of disability. N6-methyladenosine (m6A) is the most abundant internal modification in eukaryotic messenger RNAs and is involved in various diseases and cellular processes by modulating mRNA fate. However, the critical role of m6A regulation in IVD degeneration remains unclear. Nucleus pulposus cell (NPC) senescence is critical for the progression of IVD degeneration. Here, we uncovered the role and explored the regulatory mechanism of m6A in NPC senescence during IVD degeneration.

METHODS

Identification of NPC senescence during IVD degeneration was based on the analysis of tissue samples and the cellular model. ALKBH5 upregulation inducing cellular senescence was confirmed by functional experiments in vivo and in vitro. ChIP-qPCR and DNA-Pulldown were used to reveal increased ALKBH5 was regulated by KDM4A-mediated H3K9me3. Furthermore, Me-RIP-seq was performed to identify m6A hypomethylation of DNMT3B transcripts in senescent NPCs. Stability analysis showed that DNMT3B expression was enhanced for less YTHDF2 recognition and increased DNMT3B promoted NPC senescence and IVD degeneration via E4F1 methylation by in vivo and in vitro analyses.

RESULTS

Expression of ALKBH5 is enhanced during IVD degeneration and NPC senescence, due to decreased KDM4A-mediated H3K9me3 modification. Functionally, ALKBH5 causes NPC senescence by demethylating DNMT3B transcripts and in turn promoting its expression via less YTHDF2 recognition and following degradation due to transcript hypomethylation in vitro and in vivo. Increased DNMT3B promotes the development of IVD degeneration and NPC senescence, mechanistically by methylating CpG islands of E4F1 at the promoter region and thus restraining its transcription and expression.

CONCLUSIONS

Collectively, our findings reveal an epigenetic interplay mechanism in NPC senescence and IVD degeneration, presenting a critical pro-senescence role of ALKBH5 and m6A hypomethylation, highlighting the therapeutic potential of targeting the m6A/DNMT3B/E4F1 axis for treating IVD degeneration.

Protein kinases in cardiovascular diseases

ABSTRACT

Cardiovascular disease (CVD) remains the leading cause of death worldwide. Therefore, exploring the mechanism of CVDs and critical regulatory factors is of great significance for promoting heart repair, reversing cardiac remodeling, and reducing adverse cardiovascular events. Recently, significant progress has been made in understanding the function of protein kinases and their interactions with other regulatory proteins in myocardial biology. Protein kinases are positioned as critical regulators at the intersection of multiple signals and coordinate nearly every aspect of myocardial responses, regulating contractility, metabolism, transcription, and cellular death. Equally, reconstructing the disrupted protein kinases regulatory network will help reverse pathological progress and stimulate cardiac repair. This review summarizes recent researches concerning the function of protein kinases in CVDs, discusses their promising clinical applications, and explores potential targets for future treatments.

Serine/Threonine-Protein Kinase 3 Facilitates Myocardial Repair After Cardiac Injury Possibly Through the Glycogen Synthase Kinase-3β/β-Catenin Pathway

Background The neonatal heart maintains its entire regeneration capacity within days after birth. Using quantitative phosphoproteomics technology, we identified that SGK3 (serine/threonine-protein kinase 3) in the neonatal heart is highly expressed and activated after myocardial infarction. This study aimed to uncover the function and related mechanisms of SGK3 on cardiomyocyte proliferation and cardiac repair after apical resection or ischemia/reperfusion injury. Methods and Results The effect of SGK3 on proliferation and oxygen glucose deprivation/reoxygenation- induced apoptosis in isolated cardiomyocytes was evaluated using cardiomyocyte-specific SGK3 overexpression or knockdown adenovirus5 vector. In vivo, gain- and loss-of-function experiments using cardiomyocyte-specific adeno-associated virus 9 were performed to determine the effect of SGK3 in cardiomyocyte proliferation and cardiac repair after apical resection or ischemia/reperfusion injury. In vitro, overexpression of SGK3 enhanced, whereas knockdown of SGK3 decreased, the cardiomyocyte proliferation ratio. In vivo, inhibiting the expression of SGK3 shortened the time window of cardiac regeneration after apical resection in neonatal mice, and overexpression of SGK3 significantly promoted myocardial repair and cardiac function recovery after ischemia/reperfusion injury in adult mice. Mechanistically, SGK3 promoted cardiomyocyte regeneration and myocardial repair after cardiac injury by inhibiting GSK-3β (glycogen synthase kinase-3β) activity and upregulating β-catenin expression. SGK3 also upregulated the expression of cell cycle promoting genes G1/S-specific cyclin-D1, c-myc (cellular-myelocytomatosis viral oncogene), and cdc20 (cell division cycle 20), but downregulated the expression of cell cycle negative regulators cyclin kinase inhibitor P 21 and cyclin kinase inhibitor P 27. Conclusions Our study reveals a key role of SGK3 on cardiac repair after apical resection or ischemia/reperfusion injury, which may reopen a novel therapeutic option for myocardial infarction.

Dynamic Patterns of N6-Methyladenosine Profiles of Messenger RNA Correlated with the Cardiomyocyte Regenerability during the Early Heart Development in Mice

N6-Methyladenosine (m6A) plays important roles in regulating mRNA processing. Despite rapid progress in this field, little is known about the role and mechanism of m6A modification in myocardial development and cardiomyocyte regeneration. Existing studies have shown that the heart tissues of newborn mice have the capability of proliferation and regeneration, but its mechanism, particularly its relation to m6A methylation, remains unknown. Methods. To systematically profile the mRNA m6A modification pattern in the heart tissues of mice at different developmental stages, we jointly performed methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) of heart tissues of mice, respectively, aged 1 day old, 7 days old, and 28 days old. Results. We identified the linkages and association between differentially expressed mRNA transcripts and hyper or hypomethylated m6A peaks in C57BL/6J mice at different heart developmental stages. Results showed that the amount of m6A peaks and the level of m6A modification were the lowest in the heart of mice at 1 day old. By contrast, heart tissues from 7-day-old mice tended to possess the most m6A peaks and the highest global m6A level. However, the m6A characteristics of myocardial tissue changed little after 7 days old as compared to that of 1 day old. Specifically, we found 1269 downmethylated genes of 1434 methylated genes in 7-day-old mouse heart tissues as compared to those in 1-day-old mice. Hypermethylation of some specific genes may correlate with the heart's strong proliferative and regenerative capability at the first day after birth. In terms of m6A density, the tendency shifted from coding sequences (CDS) to 3′-untranslated regions (3′UTR) and stop codon with the progression of heart development. In addition, some genes demonstrated remarkable changes both in methylation and expression, like kiss1, plekha6, and megf6, which may play important roles in proliferation. Furthermore, signaling pathways highly related to proliferation such as “Wnt signaling pathway,” “ECM-receptor interaction,” and “cardiac chamber formation” were significantly enriched in 1-day-old methylated genes. Conclusions. Our results reveal a pattern that different m6A modifications are distributed in C57BL/6J heart tissue at different developmental stages, which provides new insights into a novel function of m6A methylation of mRNA in myocardial development and regeneration.

Maternal RNF114-mediated target substrate degradation regulates zygotic genome activation in mouse embryos

Zygotic genomic activation (ZGA) is a landmark event in the maternal-to-zygotic transition (MZT), and the regulation of ZGA by maternal factors remains to be elucidated. In this study, the depletion of maternal ring finger protein 114 (RNF114), a ubiquitin E3 ligase, led to developmental arrest of two-cell mouse embryos. Using immunofluorescence and transcriptome analysis, RNF114 was proven to play a crucial role in major ZGA. To study the underlying mechanism, we performed protein profiling in mature oocytes and found a potential substrate for RNF114, chromobox 5 (CBX5), ubiquitylation and degradation of which was regulated by RNF114. The overexpression of CBX5 prevented embryonic development and impeded major ZGA. Furthermore, TAB1 was abnormally accumulated in mutant two-cell embryos, which was consistent with the result of in vitro knockdown of Rnf114. Knockdown of Cbx5 or Tab1 in maternal RNF114-depleted embryos partially rescued developmental arrest and the defect of major ZGA. In summary, our study reveals that maternal RNF114 plays a precise role in degrading some important substrates during the MZT, the misregulation of which may impede the appropriate activation of major ZGA in mouse embryos.