Targeting OGF/OGFR signal to mitigate doxorubicin-induced cardiotoxicity.

Enkephalins are reportedly correlated with heart function. However, their regulation in the heart remains unexplored. This study revealed a substantial increase in circulating levels of opioid growth factor (OGF) (also known as methionine enkephalin) and myocardial expression levels of both OGF and its receptor (OGFR) in subjects treated with doxorubicin (Dox). Silencing OGFR through gene knockout or using adeno-associated virus serotype 9 carrying small hairpin RNA effectively alleviated Dox-induced cardiotoxicity (DIC) in mice. Conversely, OGF supplementation exacerbated DIC manifestations, which could be abolished by administration of the OGFR antagonist naltrexone (NTX). Mechanistically, the previously characterized OGF/OGFR/P21 axis was identified to facilitate DIC-related cardiomyocyte apoptosis. Additionally, OGFR was observed to dissociate STAT1 from the promoters of ferritin genes (FTH and FTL), thereby repressing their transcription and exacerbating DIC-related cardiomyocyte ferroptosis. To circumvent the compromised therapeutic effects of Dox on tumors owing to OGFR blockade, SiO2-based modifiable lipid nanoparticles were developed for heart-targeted delivery of NTX. The pretreatment of tumor-bearing mice with the assembled NTX nanodrug successfully provided cardioprotection against Dox toxicity without affecting Dox therapy in tumors. Taken together, this study provides a novel understanding of Dox cardiotoxicity and sheds light on the development of cardioprotectants for patients with tumors receiving Dox treatment.

An orally administered bacterial membrane protein nanodrug ameliorates doxorubicin cardiotoxicity through alleviating impaired intestinal barrier.

The cardiotoxicity caused by Dox chemotherapy represents a significant limitation to its clinical application and is a major cause of late death in patients undergoing chemotherapy. Currently, there are no effective treatments available. Our analysis of 295 clinical samples from 132 chemotherapy patients and 163 individuals undergoing physical examination revealed a strong positive correlation between intestinal barrier injury and the development of cardiotoxicity in chemotherapy patients. We developed a novel orally available and intestinal targeting protein nanodrug by assembling membrane protein Amuc_1100 (obtained from intestinal bacteria Akkermansia muciniphila), fluorinated polyetherimide, and hyaluronic acid. The protein nanodrug demonstrated favorable stability against hydrolysis compared with free Amuc_1100. The in vivo results demonstrated that the protein nanodrug can alleviate Dox-induced cardiac toxicity by improving gut microbiota, increasing the proportion of short-chain fatty acid-producing bacteria from the Lachnospiraceae family, and further enhancing the levels of butyrate and pentanoic acids, ultimately regulating the homeostasis repair of lymphocytes in the spleen and heart. Therefore, we believe that the integrity of the intestinal barrier plays an important role in the development of chemotherapy-induced cardiotoxicity. Protective interventions targeting the intestinal barrier may hold promise as a general clinical treatment regimen for reducing Dox-induced cardiotoxicity.

Deciphering the Epidemiological Characteristics and Molecular Features of bla KPC-2- or bla NDM-1-Positive Klebsiella pneumoniae Isolates in a Newly Established Hospital.

The emergence of hypervirulent carbapenem-resistant Klebsiella pneumoniae (hv-CRKP) was regarded as an emerging threat in clinical settings. Here, we investigated the prevalence of CRKP strains among inpatients in a new hospital over 1 year since its inception with various techniques, and carried out a WGS-based phylogenetic study to dissect the genomic background of these isolates. The genomes of three representative bla NDM-1-positive strains and the plasmids of four bla KPC-2-positive strains were selected for Nanopore long-read sequencing to resolve the complicated MDR structures. Thirty-five CRKP strains were identified from 193 K. pneumoniae isolates, among which 30 strains (85.7%) harbored bla KPC-2, whereas the remaining five strains (14.3%) were positive for bla NDM-1. The antimicrobial resistance profiles of bla NDM-1-positive isolates were narrower than that of bla KPC-2-positive isolates. Five isolates including two bla NDM-1-positive isolates and three bla KPC-2-positive strains could successfully transfer the carbapenem resistance phenotype by conjugation. All CRKP strains were categorized into six known multilocus sequence types, with ST11 being the most prevalent type. Phylogenetic analysis demonstrated that the clonal spread of ST11 bla KPC-2-positive isolates and local polyclonal spread of bla NDM-1-positive isolates have existed in the hospital. The bla NDM-1 gene was located on IncX3, IncFIB/IncHI1B, and IncHI5-like plasmids, of which IncFIB/IncHI1B plasmid has a novel structure. By contrast, all ST11 isolates shared the similar bla KPC-2-bearing plasmid backbone, and 11 of them possessed pLVPK-like plasmids. In addition, in silico virulome analysis, Galleria mellonella larvae infection assay, and siderophore secretion revealed the hypervirulence potential of most bla KPC-2-positive strains. Given that these isolates also had remarkable environmental adaptability, targeted measures should be implemented to prevent the grave consequences caused by hv-CRKP strains in nosocomial settings.

First case of infective endocarditis caused by Methylobacterium radiotolerans.

Methylobacterium radiotolerans has only been identified in blood samples from end-stage renal failure or leukaemia patients in clinic. Here, we report a case of infective endocarditis (IE) caused by M. radiotolerans. 16S rRNA sequencing and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) were used to identify the bacteria isolated from cardiac vegetation. A drug sensitivity test was conducted by disk diffusion on blood Mueller-Hinton agar. This isolate was identified as M. radiotolerans, which was susceptible to aminoglycosides and ciprofloxacin. Our findings also suggest that M. radiotolerans can cause infection in a patient with normal immune function.

ARRB1-Promoted NOTCH1 Degradation Is Suppressed by OncomiR miR-223 in T-cell Acute Lymphoblastic Leukemia.

T-cell acute lymphoblastic leukemia (T-ALL) is a type of aggressive leukemia with inferior prognosis. Although activating mutations of NOTCH1 are observed in most T-ALL cases, these mutations alone are not sufficient to drive the full development of T-ALL. ß-Arrestins (ARRB) are versatile and multifunctional adapter proteins that regulate diverse cellular functions, including promoting the development of cancer. However, the role of ARRBs in T-ALL has largely remained elusive. In this study, we showed that ARRB1 is expressed at low levels in assayed T-ALL clinical samples and cell lines. Exogenous ARRB1 expression inhibited T-ALL proliferation and improved the survival of T-ALL xenograft animals. ARRB1 facilitated NOTCH1 ubiquitination and degradation through interactions with NOTCH1 and DTX1. Mechanistically, the oncogenic miRNA (oncomiR) miR-223 targets the 3'-UTR of ARRB1 (BUTR) and inhibits its expression in T-ALL. Furthermore, overexpression of the ARRB1-derived miR-223 sponge suppressed T-ALL cell proliferation and induced apoptosis. Collectively, these results demonstrate that ARRB1 acts as a tumor suppressor in T-ALL by promoting NOTCH1 degradation, which is inhibited by elevated miR-223, suggesting that ARRB1 may serve as a valid drug target in the development of novel T-ALL therapeutics.Significance: These findings highlight a novel tumor suppressive function of the adaptor protein ß-arrestin1 in T-ALL.

ß-Arrestin1 promotes the self-renewal of the leukemia-initiating cell-enriched subpopulation in B-lineage acute lymphoblastic leukemia related to DNMT1 activity.

The self-renewal ability of the leukemia initiating cell-enriched subpopulation is critical for leukemia initiation and maintenance. However, the regulation of leukemia initiating cells for the leukemia progression is poorly understood. In this study, we observed that ß-Arrestin1, a multiple-function protein, is elevated in leukemia initiating cells-enriched fraction from B-lineage acute lymphoblastic leukemia patients. The loss of ß-Arrestin1 in leukemia initiating cells-enriched fraction attenuates its self-renewal capacity both in vitro and in vivo. Further experiments showed that the mRNA expression level of ß-Arrestin1 is negatively correlated with that of PTEN in leukemia initiating cells-enriched fraction. Moreover, DNA methylation of the PTEN promoter region, the activity and expression of DNMTs were enhanced in the leukemia initiating cells-enriched fraction. The inhibition of DNMT1 activity impaired the self-renewal and increased expression of PTEN of leukemia initiating cells-enriched fraction. In addition, depletion of ß-Arrestin1 significantly decreased DNMT1 activity and PTEN methylation, and consistently increased PTEN expression in leukemia initiating cells-enriched fraction. Our study reveals a novel function of ß-Arrestin1 in the regulation of the self-renewal of leukemia initiating cells-enriched fraction from B-lineage acute lymphoblastic leukemia patients related to DNMT1 activity, indicating that ß-Arrestin1 is a potential therapeutic target in B-lineage acute lymphoblastic leukemia.

[Effects of Epstein-Barr virus and cytomegalovirus infection on childhood acute lymphoblastic leukemia gene methylation].

OBJECTIVE: To investigate the associations between Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV) infections and the methylation levels of PTEN and hTERT genes and explore their roles in children with acute lymphoblastic leukemia (ALL). METHODS: Blood samples from 100 children with newly diagnosed acute lymphoblastic leukemia were centrifuged for serological detection of EBV and HCMV, and the patients were divided accordingly into EBV-infected group (n=20), HCMV-infected group (n=14), EBV and HCMV co-infected group (n=41), and non-infected group (control group, n=15). DNA was extracted from peripheral blood mononuclear cells (PBMCs) and modified with bisulfite ammonia sodium. The methylation levels of the promoters of PTEN and hTERT genes were detected with methylation-specific polymerase chain reaction (MS-PCR). RESULTS: Compared with those in non-infected group and EBV- or HCMV-infected group, the methylation levels of PTEN gene in the co-infected group were significantly decreased (P<0.05) while the methylation levels of hTERT gene significantly increased (P<0.05). CONCLUSION: In children with acute lymphoblastic leukemia, EBV and HCMV co-infection cause changes in the methylation levels of PTEN and hTERT. These results may be associated with epigenetic changes caused by viral infections, and further studies are needed to further verify this hypothesis.