Efficacy of Voluntary Medical Male Circumcision to Prevent HIV Infection Among Men Who Have Sex With Men : A Randomized Controlled Trial.

BACKGROUND: Observational studies suggest that voluntary medical male circumcision (VMMC) may lower HIV risk among men who have sex with men (MSM). A randomized controlled trial (RCT) is needed to confirm this. OBJECTIVE: To assess the efficacy of VMMC in preventing incident HIV infection among MSM. DESIGN: An RCT with up to 12 months of follow-up. (Chinese Clinical Trial Registry: ChiCTR2000039436). SETTING: 8 cities in China. PARTICIPANTS: Uncircumcised, HIV-seronegative men aged 18 to 49 years who self-reported predominantly practicing insertive anal intercourse and had 2 or more male sex partners in the past 6 months. INTERVENTION: VMMC. MEASUREMENTS: Rapid testing for HIV was done at baseline and at 3, 6, 9, and 12 months. Behavioral questionnaires and other tests for sexually transmitted infections were done at baseline, 6 months, and 12 months. The primary outcome was HIV seroconversion using an intention-to-treat analysis. RESULTS: The study enrolled 124 men in the intervention group and 123 in the control group, who contributed 120.7 and 123.1 person-years of observation, respectively. There were 0 seroconversions in the intervention group (0 infections [95% CI, 0.0 to 3.1 infections] per 100 person-years) and 5 seroconversions in the control group (4.1 infections [CI, 1.3 to 9.5 infections] per 100 person-years). The HIV hazard ratio was 0.09 (CI, 0.00 to 0.81; P = 0.029), and the HIV incidence was lower in the intervention group (log-rank P = 0.025). The incidence rates of syphilis, herpes simplex virus type 2, and penile human papillomavirus were not statistically significantly different between the 2 groups. There was no evidence of HIV risk compensation. LIMITATION: Few HIV seroconversions and limited follow-up period. CONCLUSION: Among MSM who predominantly practice insertive anal intercourse, VMMC is efficacious in preventing incident HIV infection; MSM should be included in VMMC guidelines. PRIMARY FUNDING SOURCE: The National Science and Technology Major Project of China.

Factors associated with immunological non-response after ART initiation: a retrospective observational cohort study.

BACKGROUND: Among people living with HIV (PLHIV) on antiretroviral therapy (ART), the mortality of immunological non-responders (INRs) is higher than that of immunological responders (IRs). However, factors associated with immunological non-response following ART are not well documented. METHODS: We obtained data for HIV patients from the National Free Antiretroviral Treatment Program database in China. Patients were grouped into IRs (CD4 cell count ≥ 350 cells/µl after 24 months' treatment), immunological incomplete responders (ICRs) (200-350 cells/µl) and INRs (< 200 cells/µl). Multivariable logistic regression was used to assess factors associated with immunological non-response. RESULTS: A total of 3900 PLHIV were included, among whom 2309 (59.2%) were IRs, 1206 (30.9%) ICRs and 385 (9.9%) INRs. In multivariable analysis, immunological non-response was associated with being male (2.07, 1.39-3.09), older age [40-49 years (vs. 18-29 years): 2.05, 1.29-3.25; 50-59 years: 4.04, 2.33-7.00; ≥ 60 years: 5.51, 2.84-10.67], HBV co-infection (1.63, 1.14-2.34), HCV co-infection (2.01, 1.01-4.02), lower CD4 + T cell count [50-200 cells/µl (vs. 200-350 cells/µl): 40.20, 16.83-96.01; < 50 cells/µl: 215.67, 85.62-543.26] and lower CD4/CD8 ratio (2.93, 1.98-4.34) at baseline. Compared with patients treated with non-nucleoside reverse transcriptase inhibitors (NNRTIs) based regimens, those receiving protease inhibitors (PIs) based regimens were less likely to be INRs (0.47, 0.26-0.82). CONCLUSIONS: We found a sizable immunological non-response rate among HIV-infected patients. Being male, older age, coinfection with HBV and HCV, lower CD4 + T cell count and lower CD4/CD8 ratio are risk factors of immunological non-response, whereas PIs-based regimens is a protective factor.

Paraptosis: a non-classical paradigm of cell death for cancer therapy.

Due to the sustained proliferative potential of cancer cells, inducing cell death is a potential strategy for cancer therapy. Paraptosis is a mode of cell death characterized by endoplasmic reticulum (ER) and/or mitochondrial swelling and cytoplasmic vacuolization, which is less investigated. Considerable evidence shows that paraptosis can be triggered by various chemical compounds, particularly in cancer cells, thus highlighting the potential application of this non-classical mode of cell death in cancer therapy. Despite these findings, there remain significant gaps in our understanding of the role of paraptosis in cancer. In this review, we summarize the current knowledge on chemical compound-induced paraptosis. The ER and mitochondria are the two major responding organelles in chemical compound-induced paraptosis, which can be triggered by the reduction of protein degradation, disruption of sulfhydryl homeostasis, overload of mitochondrial Ca2+, and increased generation of reactive oxygen species. We also discuss the stumbling blocks to the development of this field and the direction for further research. The rational use of paraptosis might help us develop a new paradigm for cancer therapy.

Metabolism and the UPR(mt).

During mitochondrial dysfunction or the accumulation of unfolded proteins within mitochondria, cells employ a transcriptional response known as the mitochondrial unfolded protein response (UPR(mt)) to promote cell survival along with the repair and recovery of defective mitochondria. Considerable progress has been made in understanding how cells monitor mitochondrial function and activate the response, as well as in identifying scenarios where the UPR(mt) plays a protective role, such as during bacterial infection, hematopoietic stem cell maintenance, or general aging. To date, much of the focus has been on the role of the UPR(mt) in maintaining or re-establishing protein homeostasis within mitochondria by transcriptionally inducing mitochondrial molecular chaperone and protease genes. In this review, we focus on the metabolic adaptations or rewiring mediated by the UPR(mt) and how this may contribute to the resolution of mitochondrial unfolded protein stress and cell-type-specific physiology.

Altered gut microbiota is associated with different immunologic responses to antiretroviral therapy in HIV-infected men who have sex with men.

The association between gut microbiota and immunologic nonresponse among people living with HIV (PLHIV) on antiretroviral therapy (ART) is not well documented. This study aimed to characterize gut microbiota among HIV-infected men who have sex with men (MSM) with different immunologic responses. We recruited HIV-infected MSM and HIV-uninfected MSM (healthy controls, HC) in Guangzhou, June-October 2021. HIV-infected MSM were grouped into good immunological responders (GIR) (CD4 + T cell count ≥ 350 cells/µL) and poor immunological responders (PIR) (<350 cells/µL). Blood and stool samples were collected. Microbial translocation in serum was performed using enzyme-linked immunosorbent assay (ELISA). Bacterial 16S ribosomal DNA sequencing was performed on stool samples, and microbial metabolites were obtained through gas chromatography-mass spectrometry. 56 GIR, 41 PIR, and 51 HC were included. Microbial translocation marker soluble cluster of differentiation 14 (sCD14) in both GIR and PIR groups was significantly higher than that in HC. Compared with PIR or HC groups, the genera of Coprococcus, Blautia, Clostridium, and SMB53 were decreased, whereas Megamonas and Megasphaera were more abundant in GIR group. Compared with GIR or PIR groups, Bifidobacterium, Collinsella, Faecalibacterium, Oscillospira, and Roseburia were more abundant, whereas Escherichia was decreased in HC group. The levels of benzenoids, imidazoles, phenylpropanoic acids, phenylpropanoids, and pyridines showed strongly significant correlations between differential genera. This study presented a comprehensive landscape of gut microbiota in PLHIV with different treatment outcomes. Megamonas, Coprococcus and Blautia were the major genera correlated with different immunologic responses in PLHIV.

Impact of combination preventative interventions on hospitalization and death under the pandemic of SARS-CoV-2 Omicron variant in China.

With a large population most susceptible to Omicron and emerging SARS-CoV-2 variants, China faces uncertain scenarios if reopening its border. Thus, we aimed to predict the impact of combination preventative interventions on hospitalization and death. An age-stratified susceptible-infectious-quarantined-hospitalized-removed-susceptible (SIQHRS) model based on the new guidelines of COVID-19 diagnosis and treatment (the ninth edition) was constructed to simulate the transmission dynamics of Omicron within 365 days. At baseline, we assumed no interventions other than 60% booster vaccination in individuals aged ≤60 years and 80% in individuals aged >60 years, quarantine and hospitalization. Oral antiviral medications for COVID-19 and nonpharmaceutical interventions (NPIs) such as social distancing and antigen self-testing were considered in subsequent scenarios. Sensitivity analyses were conducted to reflect different levels of interventions. A total of 0.73 billion cumulative quarantines (95% CI 0.53-0.83), 33.59 million hospitalizations (22.41-39.31), and 0.62 million deaths (0.40-0.75) are expected in 365 days. The case fatality rate with pneumonia symptoms (moderate, severe and critical illness) is expected to be 1.83% (1.68-1.99%) and the infected fatality rate is 0.38‰ (0.33-0.4‰). The highest existing hospitalization and ICU occupations are 3.11 (0.30-3.85) and 20.33 (2.01-25.20) times of capacity, respectively. Sensitivity analysis showed that interventions can be adjusted to meet certain conditions to reduce the total number of infections and deaths. In conclusion, after sufficient respiratory and ICU beds are prepared and the relaxed NPIs are in place, the SARS-CoV-2 Omicron variant would not seriously impact the health system.

Changes in HPV prevalence, incidence, and clearance following the use of HIV pre-exposure prophylaxis (PrEP) among MSM in Xinjiang, China: An observational cohort study.

The association between HIV pre-exposure prophylaxis (PrEP) and the natural history of human papillomavirus (HPV) has not been well documented. Our objective was to evaluate the impact of PrEP on the prevalence, incidence, and clearance of anal HPV among men who have sex with men (MSM). Sexually active, HIV-negative MSM aged 18 years and older in Xinjiang, China since September 1, 2016, were enrolled in an ongoing observational cohort study of HPV. At baseline and every 6 months, an anal swab was taken to test for HPV and a questionnaire on sociodemographic characteristics and sexual behaviors was collected. Those who consented to receive PrEP were enrolled in an open-label PrEP intervention study from November 1, 2019, to June 30, 2021. This study analyzed data from participants present in the HPV cohort between November 1, 2019, and June 30, 2021. We compared the prevalence, incidence, and clearance of anal HPV between men who received PrEP (PrEP users) and those who did not (non-PrEP users), and compared men before and after initiating PrEP. We calculated prevalence ratios (PRs), incidence rate ratios (IRRs), and clearance rate ratios (CRRs) for both comparisons. Of the 870 participants present in the HPV cohort during the period between November 1, 2019, and June 30, 2021, 859 had adequate ß-globin for HPV genotype testing and were included in our study. Among them, 429 were PrEP users, while 430 were non-PrEP users. Median age was 32 years (interquartile range [IQR]: 26-38). Among PrEP users, 217 were tested for anal HPV before PrEP initiation. PrEP users had lower prevalence of HPV 45, 51, and 54 (PRs: 0.27 [95% CI: 0.09-0.80], 0.42 [0.21-0.85], and 0.41 [0.17-0.99], respectively) and lower clearance of HPV 16 (CRR: 0.31 [0.10-0.91]) compared with non-PrEP users. PrEP users exhibited lower prevalence of HPV 51 (PR: 0.31 [0.12-0.84]), lower incidence of HPV 6, 11, 16, 39 and 61 (IRRs: 0.34 [0.13-0.90], 0.26 [0.08-0.87], 0.44 [0.21-0.91], 0.21 [0.05-0.93], and 0.19 [0.04-0.82], respectively), as well as higher clearance of HPV 52 (CRR: 2.17 [1.08-4.35]) after PrEP initiation. PrEP use may lower the risk of HPV infection among MSM in Xinjiang, China. Our findings further extend the knowledge of the impact of PrEP on sexually transmitted infections.

Monkeypox awareness and low vaccination hesitancy among men who have sex with men in China.

Men who have sex with men (MSM) have been recommended for targeted monkeypox vaccination. We aimed to investigate monkeypox awareness and explore the correlates of monkeypox vaccination hesitancy among MSM in China. We conducted a cross-sectional survey from August 10 to September 9, 2022. Awareness related to monkeypox and attitude toward monkeypox vaccination among MSM aged ≥18 years were collected. Multivariable logistic regression was applied to evaluate correlates of vaccination hesitancy. The discrepancy in awareness between subgroups regarding HIV status was assessed. A total of 1090 MSM were included (age: median 30 years, interquartile range [IQR], 25-35; HIV-infected: 53.12%). Only 13.85% of respondents expressed high monkeypox vaccination hesitancy. Hesitancy was associated with no fixed income (adjuster odds ratio [aOR], 2.46, 95% confidence interval [CI], 1.48-4.11), infrequent information following (sometimes, 3.01, 1.55-5.83; seldom or never, 5.66, 2.58-12.45), and lack of worries about monkeypox endemic (1.78, 1.11-2.87). Participants who believed that HIV-infected cases accounted for a smaller proportion (1.62, 1.01-2.60), disagreed that monkeypox virus could be detected in semen (2.21, 1.26-3.88), and considered either replication-competent (1.84, 1.14-2.96) or replication-deficient (4.80, 2.26-10.21) monkeypox vaccine unsuitable for HIV-infected people were generally more hesitant. Compared with HIV-uninfected MSM, HIV-infected MSM supported more for vaccination promotion. MSM in China had low hesitancy toward monkeypox vaccination. Safety and affordability of vaccine and availability of information were essential aspects to reduce hesitancy. Education on vaccination benefits should be encouraged to promote future vaccination plans.

Risk Factors of Clinical Relapses in Pediatric Luminal Crohn's Disease: A Retrospective Cohort Study.

INTRODUCTION: There is currently little knowledge on factors associated with the relapse of Crohn's disease (CD) in children. The aims of this study were to describe the risk factors associated with relapse in pediatric CD and the changes in the relapse rate over the past decade. METHODS: Patients younger than 18 years and diagnosed between 2009 and 2019 were included in this retrospective cohort study. Clinical, endoscopic, histological, and laboratory data, as well as induction and maintenance treatments, were collected from the medical records. Survival analyses and Cox regression models were used to assess the impact of these risk factors on relapse. RESULTS: Six hundred thirty-nine patients were included. There was a decrease in the clinical relapse rate over the past decade: 70.9% of the patients diagnosed between 2009 and 2014 relapsed as compared with 49.1% of the patients diagnosed between 2015 and 2019 (P < 0.0001). The following variables were associated with clinical relapse: female sex (adjusted hazard ratio [aHR] = 1.52, P = 0.0007), exposure to oral 5-ASA (aHR = 1.44, P = 0.04), use of immunomodulatory agents compared with tumor necrosis factor-alpha inhibitors (methotrexate aHR = 1.73, P = 0.003; thiopurines aHR = 1.63, P = 0.002), presence of granulomas (aHR = 1.34, P = 0.02) and increased eosinophils on intestinal biopsies (aHR = 1.36, P = 0.02), high levels of C-reactive protein (aHR = 1.01, P < 0.0001) and fecal calprotectin (aHR = 1.08, P < 0.0001), and low serum infliximab levels (aHR = 2.32, P = 0.001). DISCUSSION: Relapse of pediatric CD has decreased in the past decade. The risk of relapse is significantly associated with clinical, endoscopic, histological, and laboratory variables and treatment strategies.

Effects of baloxavir and oseltamivir antiviral therapy on the transmission of seasonal influenza in China: A mathematical modeling analysis.

New antiviral influenza treatments can effectively alleviate illness while reducing viral shedding. However, how such effects can translate into lower population infections of seasonal influenza in China remains unknown. To shed light on the public health impacts of novel antiviral agents for influenza, we constructed a dynamic transmission model to simulate the seasonal influenza epidemics in China. Two antivirus treatments, baloxavir and oseltamivir, were evaluated by estimating their impacts on the incidences of influenza infection in a single flu season. In the base-case analysis of a 10% antiviral treatment uptake rate, 2760 and 3420 per 10 000 persons contracted influenza under the treatment of baloxavir and oseltamivir, respectively. These incidence rates amounted to an 18.90% relative risk reduction (RRR) of infection associated with baloxavir in relation to oseltamivir. The corresponding RRR was 82.16% when the antiviral treatment uptake rate was increased to 35%. In addition, the peak of the prevalence of infected individuals per 10 000 persons under the baloxavir treatment was 177 (range: 93-274) fewer than that of oseltamivir. Our analyses suggest that the baloxavir treatment strategy reduces the incidence of influenza in China compared with oseltamivir in the setting of a seasonal flu epidemic. Also, increasing the uptake rate of antiviral treatment can potentially prevent millions of infections during a single flu season.

Vaccination strategy for preventing the spread of SARS-CoV-2 in the limited supply condition: A mathematical modeling study.

To mitigate SARS-CoV-2 transmission, vaccines have been urgently approved. With their limited availability, it is critical to distribute the vaccines reasonably. We simulated the SARS-CoV-2 transmission for 365 days over four intervention periods: free transmission, structural mitigation, personal mitigation, and vaccination. Sensitivity analyses were performed to obtain robust results. We further evaluated two proposed vaccination allocations, including one-dose-high-coverage and two-doses-low-coverage, when the supply was low. 33.35% (infection rate, 2.68 in 10 million people) and 40.54% (2.36) of confirmed cases could be avoided as the nonpharmaceutical interventions (NPIs) adherence rate rose from 50% to 70%. As the vaccination coverage reached 60% and 80%, the total infections could be reduced by 32.72% and 41.19%, compared to the number without vaccination. When the durations of immunity were 90 and 120 days, the infection rates were 2.67 and 2.38. As the asymptomatic infection rate rose from 30% to 50%, the infection rate increased 0.92 (SD, 0.16) times. Conditioned on 70% adherence rate, with the same amount of limited available vaccines, the 20% and 40% vaccination coverage of one-dose-high-coverage, the infection rates were 2.70 and 2.35; corresponding to the two-doses-low-coverage with 10% and 20% vaccination coverage, the infection rates were 3.22 and 2.92. Our results indicated as the duration of immunity prolonged, the second wave of SARS-CoV-2 would be delayed and the scale would be declined. On average, the total infections in two-doses-low-coverage was 1.48 times (SD, 0.24) as high as that in one-dose-high-coverage. It is crucial to encourage people in order to improve vaccination coverage and establish immune barriers. Particularly when the supply is limited, a wiser strategy to prevent SARS-CoV-2 is equally distributing doses to the same number of individuals. Besides vaccination, NPIs are equally critical to the prevention of widespread of SARS-CoV-2.

Imidazolyl-Phenylcarbazole-Based Host Materials and Their Use for Co-host Designs in Phosphorescent OLEDs.

In recent years, owing to the demand for high-efficiency phosphorescent organic light-emitting devices (PhOLEDs), many studies have been conducted on the development of bipolar host materials. A series of imidazolyl-phenylcarbazole-based host materials, i. e., im-CzP, im-CzPCz, im-CzPtBu, and im-OCzP, were synthesized to obtain high-efficiency green and red-emitting PhOLEDs. With im-OCzP as the host, satisfactory peak efficiencies of 22.2 (77.0 cd A-1 and 93.1 lm W-1 ) and 14.1 % (9.0 cd A-1 and 10.1 lm W-1 ) could be obtained, respectively. To further improve the performance of the devices, an electron transport material, bis-4,6-(3,5-di-3-pyridylphenyl)-2-methylpyrimidine (B3PyMPM) was selected to construct a co-hosted system. The efficiency of im-OCzP combined with B3PyMPM forming co-hosts could also achieve high values of 23.0 (80.0 cd A-1 and 98.8 lm W-1 ) and 16.5 % (10.2 cd A-1 and 13.4 lm W-1 ) for green and red PhOLEDs, respectively. These results exhibited that the proposed bipolar hosts have great flexibility in adjusting the carrier balance of EML in OLEDs, demonstrating their ingenious design and high potential.

Risk Compensation in Voluntary Medical Male Circumcision Programs.

PURPOSE OF REVIEW: Evidence from clinical trials identified the effectiveness of voluntary medical male circumcision (VMMC) as an additional strategy to reduce the risk of HIV transmission from women to men. However, concerns about post-circumcision sexual risk compensation may hinder the scale-up of VMMC programs. We reviewed the evidence of changes in risky sexual behaviors after circumcision, including condomless sex, multiple sex partners, and early resumption of sex after surgery. RECENT FINDINGS: Most clinical trial data indicate that condomless sex and multiple partners did not increase for men after circumcision, and early resumption of sex is rare. Only one post-trial surveillance reports that some circumcised men had more sex partners after surgery, but this did not offset the effect of VMMC. Conversely, qualitative studies report that a small number of circumcised men had increased risky sexual behaviors, and community-based research reports that more men resumed sex early after surgery. With the large-scale promotion and expansion of VMMC services, it may be challenging to maintain effective sexual health educations due to various restrictions. Misunderstandings of the effect of VMMC in preventing HIV infection are the main reason for increasing risky sexual behaviors after surgery. Systematic and practical sexual health counseling services should be in place on an ongoing basis to maximize the effect of VMMC.

Maintenance and propagation of a deleterious mitochondrial genome by the mitochondrial unfolded protein response.

Mitochondrial genomes (mitochondrial DNA, mtDNA) encode essential oxidative phosphorylation (OXPHOS) components. Because hundreds of mtDNAs exist per cell, a deletion in a single mtDNA has little impact. However, if the deletion genome is enriched, OXPHOS declines, resulting in cellular dysfunction. For example, Kearns-Sayre syndrome is caused by a single heteroplasmic mtDNA deletion. More broadly, mtDNA deletion accumulation has been observed in individual muscle cells and dopaminergic neurons during ageing. It is unclear how mtDNA deletions are tolerated or how they are propagated in somatic cells. One mechanism by which cells respond to OXPHOS dysfunction is by activating the mitochondrial unfolded protein response (UPR(mt)), a transcriptional response mediated by the transcription factor ATFS-1 that promotes the recovery and regeneration of defective mitochondria. Here we investigate the role of ATFS-1 in the maintenance and propagation of a deleterious mtDNA in a heteroplasmic Caenorhabditis elegans strain that stably expresses wild-type mtDNA and mtDNA with a 3.1-kilobase deletion (∆mtDNA) lacking four essential genes. The heteroplasmic strain, which has 60% ∆mtDNA, displays modest mitochondrial dysfunction and constitutive UPR(mt) activation. ATFS-1 impairment reduced the ∆mtDNA nearly tenfold, decreasing the total percentage to 7%. We propose that in the context of mtDNA heteroplasmy, UPR(mt) activation caused by OXPHOS defects propagates or maintains the deleterious mtDNA in an attempt to recover OXPHOS activity by promoting mitochondrial biogenesis and dynamics.

Human papillomavirus prevalence among men who have sex with men in China: a systematic review and meta-analysis.

Human papillomavirus (HPV) infection among men who have sex with men (MSM) in China is underreported. We performed a systematic review and meta-analysis to clarify site-specific HPV prevalence among MSM in China. We searched both English and Chinese databases for all studies published before April 1, 2020, that reported HPV prevalence among MSM in China. Random-effects meta-analysis was used to calculate summary estimates. Thirty-four articles were eligible, where 32, 5, and 2 articles reported HPV prevalence at the anus, penis, and oral cavity, respectively. The estimated prevalence of anal HPV among MSM in China was 85.1% (HIV-positive), 53.6% (HIV-negative), and 59.2% (unknown HIV status), with HPV genotypes being predominated by HPV 6, 11, 16, 18, 52, and 58. Any HPV and high-risk (HR) HPV was more common in northern China, while low-risk HPV was more common in southern China. HPV prevalence increased with age among HIV-negative MSM, from 40.5% (aged < 20 years) to 57.2% (aged ≥ 40 years). High prevalence of any HPV (HIV+: 95.1%; HIV-: 97.7%) and multiple infections (HIV+: 75.9%; HIV-: 41.7%) was found in anogenital warts among MSM. HPV is common among MSM in China. MSM living with HIV and/or anogenital warts were at disproportionate risk for HR HPV. Younger MSM were found to have a lower HPV prevalence. HPV vaccines would have prevented the majority of infections if given before sex debut. HPV at anatomical sites other than the anus, incident HPV infection, and the cost-effectiveness of HPV vaccination in this population are worth further investigation.

Hspb7 is a cardioprotective chaperone facilitating sarcomeric proteostasis.

Small heat shock proteins are chaperones with variable mechanisms of action. The function of cardiac family member Hspb7 is unknown, despite being identified through GWAS as a potential cardiomyopathy risk gene. We discovered that zebrafish hspb7 mutants display mild focal cardiac fibrosis and sarcomeric abnormalities. Significant mortality was observed in adult hspb7 mutants subjected to exercise stress, demonstrating a genetic and environmental interaction that determines disease outcome. We identified large sarcomeric proteins FilaminC and Titin as Hspb7 binding partners in cardiac cells. Damaged FilaminC undergoes autophagic processing to maintain sarcomeric homeostasis. Loss of Hspb7 in zebrafish or human cardiomyocytes stimulated autophagic pathways and expression of the sister gene encoding Hspb5. Inhibiting autophagy caused FilaminC aggregation in HSPB7 mutant human cardiomyocytes and developmental cardiomyopathy in hspb7 mutant zebrafish embryos. These studies highlight the importance of damage-processing networks in cardiomyocytes, and a previously unrecognized role in this context for Hspb7.

Deletion of the Infectious spleen and kidney necrosis virus ORF069L reduces virulence to mandarin fish Siniperca chuatsi.

Mandarin fish (Siniperca chuatsi) is a significant cultured species with high added value in China. With the expansion of farming, diseases of mandarin fish such as Infectious spleen and kidney necrosis virus (ISKNV) diseases are becoming more and more serious. Human endogenous retrovirus subfamily H long terminal repeat associating protein 2 (HHLA2) is a type 1 transmembrane molecule with three extracellular Ig domains (IgV-IgC-IgV) and plays important roles in the T cell proliferation and tumorigenesis. The HHLA2-homologues have not been found in virus. In this study, a viral HHLA2 protein encoded by ISKNV ORF069L was identified and the virulence of the deleted ORF069L reconstruction ISKNV strain (ΔORF069L) was investigated. ISKNV ORF069L gene was predicted to encode a 222-amino acids peptide. The bioinformation analysis revealed that ISKNV ORF069L contained an Ig HHLA2 domain and was homologous to vertebrate B7-CD28 family proteins. The recombinant virus strain of ΔORF069L was constructed by homologous recombination technology. The virus titer and growth curves between ISKNV wild type (WT) and ΔORF069L on cellular level showed no significant differences indicating that the ORF069L did not influence the ISKNV replication. The expression levels of immune-related genes (Mx1, IL-1ß, IL-8, TNF-a and IgM) were increased in fish infected with ΔORF069L, compared to those in fish infected with ISKNV WT. Furthermore, the lethality caused by ΔORF069L declined by 40% compared with ISKNV WT, indicating that ORF069L was a virulence gene of ISKNV. Most importantly, the protection rate was nearly 100% for fish immunized with ΔORF069L strain. Those results suggested that ΔORF069L could be developed as a potential attenuated vaccine against ISKNV. Our work will be beneficial to promote the development of gene deletion attenuated vaccines for ISKNV disease.

In vivo cardiac reprogramming contributes to zebrafish heart regeneration.

Despite current treatment regimens, heart failure remains the leading cause of morbidity and mortality in the developed world due to the limited capacity of adult mammalian ventricular cardiomyocytes to divide and replace ventricular myocardium lost from ischaemia-induced infarct. Hence there is great interest to identify potential cellular sources and strategies to generate new ventricular myocardium. Past studies have shown that fish and amphibians and early postnatal mammalian ventricular cardiomyocytes can proliferate to help regenerate injured ventricles; however, recent studies have suggested that additional endogenous cellular sources may contribute to this overall ventricular regeneration. Here we have developed, in the zebrafish (Danio rerio), a combination of fluorescent reporter transgenes, genetic fate-mapping strategies and a ventricle-specific genetic ablation system to discover that differentiated atrial cardiomyocytes can transdifferentiate into ventricular cardiomyocytes to contribute to zebrafish cardiac ventricular regeneration. Using in vivo time-lapse and confocal imaging, we monitored the dynamic cellular events during atrial-to-ventricular cardiomyocyte transdifferentiation to define intermediate cardiac reprogramming stages. We observed that Notch signalling becomes activated in the atrial endocardium following ventricular ablation, and discovered that inhibiting Notch signalling blocked the atrial-to-ventricular transdifferentiation and cardiac regeneration. Overall, these studies not only provide evidence for the plasticity of cardiac lineages during myocardial injury, but more importantly reveal an abundant new potential cardiac resident cellular source for cardiac ventricular regeneration.

The novel transmembrane protein Tmem2 is essential for coordination of myocardial and endocardial morphogenesis.

Coordination between adjacent tissues plays a crucial role during the morphogenesis of developing organs. In the embryonic heart, two tissues - the myocardium and the endocardium - are closely juxtaposed throughout their development. Myocardial and endocardial cells originate in neighboring regions of the lateral mesoderm, migrate medially in a synchronized fashion, collaborate to create concentric layers of the heart tube, and communicate during formation of the atrioventricular canal. Here, we identify a novel transmembrane protein, Tmem2, that has important functions during both myocardial and endocardial morphogenesis. We find that the zebrafish mutation frozen ventricle (frv) causes ectopic atrioventricular canal characteristics in the ventricular myocardium and endocardium, indicating a role of frv in the regional restriction of atrioventricular canal differentiation. Furthermore, in maternal-zygotic frv mutants, both myocardial and endocardial cells fail to move to the midline normally, indicating that frv facilitates cardiac fusion. Positional cloning reveals that the frv locus encodes Tmem2, a predicted type II single-pass transmembrane protein. Homologs of Tmem2 are present in all examined vertebrate genomes, but nothing is known about its molecular or cellular function in any context. By employing transgenes to drive tissue-specific expression of tmem2, we find that Tmem2 can function in the endocardium to repress atrioventricular differentiation within the ventricle. Additionally, Tmem2 can function in the myocardium to promote the medial movement of both myocardial and endocardial cells. Together, our data reveal that Tmem2 is an essential mediator of myocardium-endocardium coordination during cardiac morphogenesis.

The regenerative capacity of zebrafish reverses cardiac failure caused by genetic cardiomyocyte depletion.

Natural models of heart regeneration in lower vertebrates such as zebrafish are based on invasive surgeries causing mechanical injuries that are limited in size. Here, we created a genetic cell ablation model in zebrafish that facilitates inducible destruction of a high percentage of cardiomyocytes. Cell-specific depletion of over 60% of the ventricular myocardium triggered signs of cardiac failure that were not observed after partial ventricular resection, including reduced animal exercise tolerance and sudden death in the setting of stressors. Massive myocardial loss activated robust cellular and molecular responses by endocardial, immune, epicardial and vascular cells. Destroyed cardiomyocytes fully regenerated within several days, restoring cardiac anatomy, physiology and performance. Regenerated muscle originated from spared cardiomyocytes that acquired ultrastructural and electrophysiological characteristics of de-differentiation and underwent vigorous proliferation. Our study indicates that genetic depletion of cardiomyocytes, even at levels so extreme as to elicit signs of cardiac failure, can be reversed by natural regenerative capacity in lower vertebrates such as zebrafish.