Genomic and phenotypic correlates of mosaic loss of chromosome Y in blood.

Mosaic loss of Y (mLOY) is the most common somatic chromosomal alteration detected in human blood. The presence of mLOY is associated with altered blood cell counts and increased risk of Alzheimer's disease, solid tumors, and other age-related diseases. We sought to gain a better understanding of genetic drivers and associated phenotypes of mLOY through analyses of whole genome sequencing of a large set of genetically diverse males from the Trans-Omics for Precision Medicine (TOPMed) program. This approach enabled us to identify differences in mLOY frequencies across populations defined by genetic similarity, revealing a higher frequency of mLOY in the European American (EA) ancestry group compared to those of Hispanic American (HA), African American (AA), and East Asian (EAS) ancestry. Further, we identified two genes ( CFHR1 and LRP6 ) that harbor multiple rare, putatively deleterious variants associated with mLOY susceptibility, show that subsets of human hematopoietic stem cells are enriched for activity of mLOY susceptibility variants, and that certain alleles on chromosome Y are more likely to be lost than others.

Predicting central cervical lymph node metastasis in papillary thyroid carcinoma with Hashimoto's thyroiditis: a practical nomogram based on retrospective study.

Background: In papillary thyroid carcinoma (PTC) patients with Hashimoto's thyroiditis (HT), preoperative ultrasonography frequently reveals the presence of enlarged lymph nodes in the central neck region. These nodes pose a diagnostic challenge due to their potential resemblance to metastatic lymph nodes, thereby impacting the surgical decision-making process for clinicians in terms of determining the appropriate surgical extent. Methods: Logistic regression analysis was conducted to identify independent risk factors associated with central lymph node metastasis (CLNM) in PTC patients with HT. Then a prediction model was developed and visualized using a nomogram. The stability of the model was assessed using ten-fold cross-validation. The performance of the model was further evaluated through the use of ROC curve, calibration curve, and decision curve analysis. Results: A total of 376 HT PTC patients were included in this study, comprising 162 patients with CLNM and 214 patients without CLNM. The results of the multivariate logistic regression analysis revealed that age, Tg-Ab level, tumor size, punctate echogenic foci, and blood flow grade were identified as independent risk factors associated with the development of CLNM in HT PTC. The area under the curve (AUC) of this model was 0.76 (95% CI [0.71-0.80]). The sensitivity, specificity, accuracy, and positive predictive value of the model were determined to be 88%, 51%, 67%, and 57%, respectively. Conclusions: The proposed clinic-ultrasound-based nomogram in this study demonstrated a favorable performance in predicting CLNM in HT PTCs. This predictive tool has the potential to assist clinicians in making well-informed decisions regarding the appropriate extent of surgical intervention for patients.

STING-deficiency in lung resident mesenchymal stromal cells contributes to the alleviation of LPS-induced lung injury.

Acute respiratory distress syndrome (ARDS) is characterized by acute diffuse inflammatory lung injury with a high mortality rate. Mesenchymal stromal cells (MSC) are pluripotent adult cells that can be extracted from a variety of tissues, including the lung. Lung-resident MSC (LR-MSC) located around vascular vessels and act as important regulators of lung homeostasis, regulating the balance between lung injury and repair processes. LR-MSC support the integrity of lung tissue by modulating immune responses and releasing trophic factors. Studies have reported that the STING pathway is involved in the progression of lung injury inflammation, but the specific mechanism is unclear. In this study, we found that STING deficiency could ameliorate lipopolysaccharides (LPS)-induced acute lung injury, STING knockout (STING KO) LR-MSC had an enhanced treatment effect on acute lung injury. STING depletion protected LR-MSC from LPS-induced apoptosis. RNA-sequencing and Western blot results showed that STING KO LR-MSC expressed higher levels of MSC immunoregulatory molecules, such as Igfbp4, Icam1, Hgf and Cox2, than WT LR-MSC. This study highlights that LR-MSC have a therapeutic role in acute lung injury, and we demonstrate that STING deficiency can enhance the immunomodulatory function of LR-MSC in controlling lung inflammation. Thus, STING can be used as an intervention target to enhance the therapeutic effect of MSC.

Nanosponge for Iron Chelation and Efflux: A Ferroptosis-Inhibiting Approach for Myocardial Infarction Therapy.

Myocardial infarction (MI), a consequence of coronary artery occlusion, triggers the degradation of ferritin, resulting in elevated levels of free iron in the heart and thereby inducing ferroptosis. Targeting myocardial ferroptosis through the chelation of excess iron has therapeutic potential for MI treatment. However, iron chelation in post ischemic injury areas using conventional iron-specific chelators is hindered by ineffective myocardial intracellular chelation, rapid clearance, and high systemic toxicity. A chitosan-desferrioxamine nanosponge (CDNS) is designed by co-crosslinking chitosan and deferoxamine through noncovalent gelation to address these challenges. This architecture facilitates direct iron chelation regardless of deferoxamine (DFO) release due to its sponge-like porous hydrogel structure. Upon cellular internalization, CDNS can effectively chelate cellular iron and facilitate the efflux of captured iron, thereby inhibiting ferroptosis and associated oxidative stress and lipid peroxidation. In MI mouse models, myocardial injection of CDNS promotes sustainable retention and the suppression of ferroptosis in the infarcted heart. This intervention improves cardiac function and alleviates adverse cardiac remodeling post-MI, leading to decreased oxidative stress and the promotion of angiogenesis due to ferroptosis inhibition by CDNS in the infarcted heart. This study reveals a nanosponge-based nanomedicine targeting myocardial ferroptosis with efficient iron chelation and efflux, offering a promising MI treatment.

Arnicolide D induces endoplasmic reticulum stress-mediated oncosis via ATF4 and CHOP in hepatocellular carcinoma cells.

Endoplasmic reticulum (ER) stress can trigger various cell death mechanisms beyond apoptosis, providing promise in cancer treatment. Oncosis, characterized by cellular swelling and increased membrane permeability, represents a non-apoptotic form of cell death. In our study, we discovered that Arnicolide D (AD), a natural sesquiterpene lactone compound, induces ER stress-mediated oncosis in hepatocellular carcinoma (HCC) cells, and this process is reactive oxygen species (ROS)-dependent. Furthermore, we identified the activation of the PERK-eIF2α-ATF4-CHOP pathway during ER stress as a pivotal factor in AD-induced oncosis. Notably, the protein synthesis inhibitor cycloheximide (CHX) was found to effectively reverse AD-induced oncosis, suggesting ATF4 and CHOP may hold crucial roles in the induction of oncosis by AD. These proteins play a vital part in promoting protein synthesis during ER stress, ultimately leading to cell death. Subsequent studies, in where we individually or simultaneously knocked down ATF4 and CHOP in HCC cells, provided further confirmation of their indispensable roles in AD-induced oncosis. Moreover, additional animal experiments not only substantiated AD's ability to inhibit HCC tumor growth but also solidified the essential role of ER stress-mediated and ROS-dependent oncosis in AD's therapeutic potential. In summary, our research findings strongly indicate that AD holds promise as a therapeutic agent for HCC by its ability to induce oncosis.

miR-362-3p inhibited the invasion and metastasis of oral squamous cell carcinoma cells by targeting the regulation of pituitary tumor-transforming gene 1.

OBJECTIVES: This study aimed to explore the effect of pituitary tumor-transforming gene 1 (PTT-G1) on the invasion and proliferation of oral squamous cell carcinoma (OSCC) cell lines under the action of miR-362-3p. METHODS: The bioinformatics online database was used to query the expression of PTTG1 in head and neck squamous cell carcinoma (HNSCC). The expression of PTTG1 in the Cal-27, HN-30, and HOK cell lines was detected by Western blot. A wound-healing assay was used to determine the effect of PTTG1 on the migration ability of the OSCC cells. The Transwell assay was used to examine the changes in cell-invasion ability. 5-ethynyl-2'-deoxyuridine (EdU) cell-proliferation assay was used to detect changes in cell-proliferation ability. Bioinformatics approach predicted the upstream miRNA of PTTG1. The targeting relationship between miR-362-3p and PTTG1 was examined by the dual luciferase assay, and quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression of miRNA in OSCC tissues. RESULTS: The ENCORI database showed that PTTG1 expression was up-regulated in OSCC tissues. Western blot confirmed that PTTG1 expression was up-regulated in Cal-27 and HN-30 cells than HOK cells. PTTG1 knockout can inhibit the migration, invasion, and proliferation of Cal-27 and HN-30 cells (P<0.05). Bioinformatics prediction websites predicted that the upstream miRNA of PTTG1 was miR-362-3p, and PTTG1 can bind to miR-362-3p. Results of qRT-PCR showed that miR-362-3p expression was downregulated in OSCC tissues compared with normal tissue (P<0.05). Transwell and EdU experiments confirmed that miR-362-3p knockdown can promote the invasion and proliferation of Cal-27 and HN-30 after PTTG1 knockdown. CONCLUSIONS: miR-362-3p can inhibit the invasion and proliferation of Cal-27 and HN-30 cells by targeting PTTG1.

An ATP "Synthase" Derived from a Single Structural Domain of Bacterial Histidine Kinase.

ATP (adenosine triphosphate) is a vital energy source for living organisms, and its biosynthesis and precise concentration regulation often depend on macromolecular machinery composed of protein complexes or complicated multidomain proteins. We have identified a single-domain protein HK853CA derived from bacterial histidine kinases (HK) that can catalyze ATP synthesis efficiently. Here, we explored the reaction mechanism and multiple factors that influence this catalysis through a combination of experimental techniques and molecular simulations. Moreover, we optimized its enzymatic activity and applied it as an ATP replenishment machinery to other ATP-dependent systems. Our results broaden the understanding of ATP biosynthesis and show that the single CA domain can be applied as a new biomolecular catalyst used for ATP supply.

A Minimally Invasive Robotic Tissue Palpation Device.

OBJECTIVE: Robot-assisted minimally invasive surgery remains limited by the absence of haptic feedback, which surgeons routinely rely on to assess tissue stiffness. This limitation hinders surgeons' ability to identify and treat abnormal tissues, such as tumors, during robotic surgery. METHODS: To address this challenge, we developed a robotic tissue palpation device capable of rapidly and non-invasively quantifying the stiffness of soft tissues, allowing surgeons to make objective and data-driven decisions during minimally invasive procedures. We evaluated the effectiveness of our device by measuring the stiffness of phantoms as well as lung, heart, liver, and skin tissues obtained from both rats and swine. RESULTS: Results demonstrated that our device can accurately determine tissue stiffness and identify tumor mimics. Specifically, in swine lung, we determined elastic modulus (E) values of 9.1 ± 2.3, 16.8 ± 1.8, and 26.0 ± 3.6 kPa under different internal pressure of the lungs (PIP) of 2, 25, and 45 cmH2O, respectively. Using our device, we successfully located a 2-cm tumor mimic embedded at a depth of 5 mm in the lung subpleural region. Additionally, we measured E values of 33.0 ± 5.4, 19.2 ± 2.2, 33.5 ± 8.2, and 22.6 ± 6.0 kPa for swine heart, liver, abdominal skin, and muscle, respectively, which closely matched existing literature data. CONCLUSION/SIGNIFICANCE: Results suggest that our robotic palpation device can be utilized during surgery, either as a stand-alone or additional tool integrated into existing robotic surgical systems, to enhance treatment outcomes by enabling accurate intraoperative identification of abnormal tissue.

Lung-Mimetic Hydrofoam Sealant to Treat Pulmonary Air Leak.

Pulmonary air leak is the most common complication of lung surgery, contributing to post-operative morbidity in up to 60% of patients; yet, there is no reliable treatment. Available surgical sealants do not match the demanding deformation mechanics of lung tissue; and therefore, fail to seal air leak. To address this therapeutic gap, a sealant with structural and mechanical similarity to subpleural lung is designed, developed, and systematically evaluated. This "lung-mimetic" sealant is a hydrofoam material that has alveolar-like porous ultrastructure, lung-like viscoelastic properties (adhesive, compressive, tensile), and lung extracellular matrix-derived signals (matrikines) to support tissue repair. In biocompatibility testing, the lung-mimetic sealant shows minimal cytotoxicity and immunogenicity in vitro. Human primary monocytes exposed to sealant matrikines in vitro upregulate key genes (MARCO, PDGFB, VEGF) known to correlate with pleural wound healing and tissue repair in vivo. In rat and swine models of pulmonary air leak, this lung-mimetic sealant rapidly seals air leak and restores baseline lung mechanics. Altogether, these data indicate that the lung-mimetic sealant can effectively seal pulmonary air leak and promote a favorable cellular response in vitro.

AKT2 deficiency alleviates doxorubicin-induced cardiac injury via alleviating oxidative stress in cardiomyocytes.

Doxorubicin (DOX), a widely used chemotherapy agent in cancer treatment, encounters limitations in clinical efficacy due to associated cardiotoxicity. This study aims to explore the role of AKT serine/threonine kinase 2 (AKT2) in mitigating DOX-induced oxidative stress within the heart through both intracellular and extracellular signaling pathways. Utilizing Akt2 knockout (KO) and Nrf2 KO murine models, alongside neonatal rat cardiomyocytes (NRCMs), we systematically investigate the impact of AKT2 deficiency on DOX-induced cardiac injury. Our findings reveal that DOX administration induces significant oxidative stress, a primary contributor to cardiac injury. Importantly, Akt2 deficiency exhibits a protective effect by alleviating DOX-induced oxidative stress. Mechanistically, Akt2 deficiency facilitates nuclear translocation of NRF2, thereby suppressing intracellular oxidative stress by promoting the expression of antioxidant genes. Furthermore, We also observed that AKT2 inhibition facilitates superoxide dismutase 2 (SOD2) expression both inside macrophages and SOD2 secretion to the extracellular matrix, which is involved in lowering oxidative stress in cardiomyocytes upon DOX stimulation. The present study underscores the important role of AKT2 in mitigating DOX-induced oxidative stress through both intracellular and extracellular signaling pathways. Additionally, our findings propose promising therapeutic strategies for addressing DOX-induced cardiomyopathy in clinic.

Cardiac injury activates STING signaling via upregulating SIRT6 in macrophages after myocardial infarction.

AIMS: This work sought to investigate the mechanism underlying the STING signaling pathway during myocardial infarction (MI), and explore the involvement and the role of SIRT6 in the process. MAIN METHODS: Mice underwent the surgery of permanent left anterior descending (LAD) artery constriction. Primary cardiomyocytes (CMs) and fibroblasts were subjected to hypoxia to mimic MI in vitro. STING expression was assessed in the infarct heart, and the effect of STING inhibition on cardiac fibrosis was explored. This study also evaluated the regulatory effect of STING by SIRT6 in macrophages. KEY FINDINGS: STING protein was increased in the infarct heart tissue, highlighting its involvement in the post-MI inflammatory response. Hypoxia-induced death of CMs and fibroblasts contributed to the upregulation of STING in macrophages, establishing the involvement of STING in the intercellular signaling during MI. Inhibition of STING resulted in a significant reduction of cardiac fibrosis at day 14 after MI. Additionally, this study identified SIRT6 as a key regulator of STING via influencing its acetylation and ubiquitination in macrophages, providing novel insights into the posttranscriptional modification and expression of STING at the acute phase after myocardial infarction. SIGNIFICANCE: This work shows the key role of SIRT6/STING signaling in the pathogenesis of cardiac injury after MI, suggesting that targeting this regulatory pathway could be a promising strategy to attenuate cardiac fibrosis after MI.

Circular RNA DNAH14 molecular mechanism in an experimental model of hepatocellular carcinoma treated with Cobalt chloride to mimic the hypoxia-like response of transcatheter arterial chemoembolization.

Transcatheter arterial chemoembolization (TACE) is the primary local treatment for patients with unresectable hepatocellular carcinoma (HCC). Numerous studies have demonstrated the pivotal role of circular RNAs (circRNAs) in TACE efficacy. This study aimed to investigate the function of circular RNA DNAH14 (circDNAH14) in TACE for HCC and to elucidate its molecular mechanisms. To simulate hypoxia conditions experienced during TACE, HCC cells were treated with cobalt chloride. The expression levels of circDNAH14, microRNA-508-3p (miR-508-3p), and Prothymosin Alpha (PTMA) were modulated via transfection for knockdown or overexpression. Cell Counting Kit-8 and 5-ethynyl-2'-deoxyuridine assays, flow cytometry, and Transwell assays, along with epithelial-mesenchymal transition (EMT) evaluations, were employed to assess cell proliferation, apoptosis, invasion, migration, and EMT. The results indicated that hypoxia treatment downregulated the expression of circDNAH14 and PTMA while upregulating miR-508-3p. Such treatment suppressed HCC cell proliferation, invasion, migration, and EMT, and induced apoptosis. Knockdown of circDNAH14 or PTMA intensified the suppressive effects of hypoxia on the malignant behaviors of HCC cells. Conversely, upregulation of miR-508-3p or PTMA mitigated the effects of circDNAH14 overexpression and knockdown, respectively. Mechanistically, circDNAH14 was found to competitively bind to miR-508-3p, thereby regulating PTMA expression. In vivo, nude mouse xenograft experiments demonstrated that circDNAH14 knockdown augmented the hypoxia-induced suppression of HCC tumor growth. In conclusion, circDNAH14 mitigates the suppressive effects of hypoxia on HCC, both in vitro and in vivo, by competitively binding to miR-508-3p and regulating PTMA expression.

Per- and polyfluoroalkyl substances, polychlorinated biphenyls, organochlorine pesticides, and polybrominated diphenyl ethers and dysregulation of MicroRNA expression in humans and animals-A systematic review.

BACKGROUND: Persistent organic pollutants (POPs) are chemicals characterized by their environmental persistence. Evidence suggests that exposure to POPs, which is ubiquitous, is associated with microRNA (miRNA) dysregulation. miRNA are key regulators in many physiological processes. It is thus of public health concern to understand the relationships between POPs and miRNA as related to health outcomes. OBJECTIVES: This systematic review evaluated the relationship between widely recognized, intentionally manufactured, POPs, including per- and polyfluoroalkyl substances (PFAS), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and organochlorine pesticides (dichlorodiphenyltrichloroethane [DDT], dichlorodiphenyldichloroethylene [DDE], hexachlorobenzene [HCB]), with miRNA expression in both human and animal studies. METHODS: We used PubMed and Embase to systematically search the literature up to September 29th, 2023. Search results for human and animal studies were included if they incorporated at least one POP of interest in relation to at least one miRNA. Data were synthesized to determine the direction and significance of associations between POPs and miRNA. We utilized ingenuity pathway analysis to review disease pathways for miRNA that were associated with POPs. RESULTS: Our search identified 38 eligible studies: 9 in humans and 29 in model organisms. PFAS were associated with decreased expression of miR-19, miR-193b, and miR-92b, as well as increased expression of miR-128, miR-199a-3p, and miR-26b across species. PCBs were associated with increased expression of miR-15a, miR-1537, miR-21, miR-22-3p, miR-223, miR-30b, and miR-34a, as well as decreased expression of miR-130a and let-7b in both humans and animals. Pathway analysis for POP-associated miRNA identified pathways related to carcinogenesis. DISCUSSION: This is the first systematic review of the association of POPs with miRNA in humans and model organisms. Large-scale prospective human studies are warranted to examine the role of miRNA as mediators between POPs and health outcomes.

Prognostic, immunity, stemness, and anticancer drug sensitivity characterization of pyroptosis related genes in non-small cell lung cancer.

BACKGROUND: Pyroptosis plays a pivotal role in the tumor immune microenvironment (TME) dynamics, particularly in non-small cell lung cancer (NSCLC). The aim of our study was to explore its effects on tumor progression, TME patterns, and the efficacy of therapeutic interventions in NSCLC. METHODS: Our investigation encompassed a thorough analysis of pyroptosis-related genes (PRGs), integrating immunohistochemistry (IHC) data, TME characteristics, stemness indices, and anticancer drug sensitivities. We aimed to analyze mRNA expression profiles across various cancers, constructing benchmark datasets to assess the clinical significance of PRGs in NSCLC. This included evaluating their association with clinical responses and efficacy. Notably, both our and HPA IHC data demonstrated significantly elevated GSDMD-N protein levels in lung squamous cell carcinoma (LUSC) tissues. RESULTS: The expression of PRGs differed significantly between tumor and normal tissues across various cancers, as validated by IHC data, and was correlated with prognosis (p < 0.05). Moreover, our investigation revealed significant differences (p < 0.05) in the expression of the PRGs among distinct TME subtypes categorized as C1 (wound healing), C3 (inflammatory), C2 (IFN-gamma dominant), C5 (immunological quiet), C4 (lymphocyte deficient), and C6 (TGF-beta dominant). Additionally, our research on anticancer drug sensitivity uncovered compelling connections between specific anticancer medications and the expression of PRGs, including GSDMD, ELANE, IL18, and CHMP4A (p < 0.05). CONCLUSION: Our study provided valuable insights into the critical role of PRGs in TME modulation, tumor stemness, and anticancer drug sensitivity across diverse cancers. Our findings illuminate the intricate relationship between pyroptosis and the TME, offering new perspectives for enhancing NSCLC treatment and prognosis.

High-throughput PRIME-editing screens identify functional DNA variants in the human genome.

Despite tremendous progress in detecting DNA variants associated with human disease, interpreting their functional impact in a high-throughput and single-base resolution manner remains challenging. Here, we develop a pooled prime-editing screen method, PRIME, that can be applied to characterize thousands of coding and non-coding variants in a single experiment with high reproducibility. To showcase its applications, we first identified essential nucleotides for a 716 bp MYC enhancer via PRIME-mediated single-base resolution analysis. Next, we applied PRIME to functionally characterize 1,304 genome-wide association study (GWAS)-identified non-coding variants associated with breast cancer and 3,699 variants from ClinVar. We discovered that 103 non-coding variants and 156 variants of uncertain significance are functional via affecting cell fitness. Collectively, we demonstrate that PRIME is capable of characterizing genetic variants at single-base resolution and scale, advancing accurate genome annotation for disease risk prediction, diagnosis, and therapeutic target identification.

ZnO nanoparticles impair autophagic flux and cell viability through the TRIM16-NRF2-p62 pathway in inflammatory keratinocytes.

PURPOSE: Zinc oxide nanoparticles (ZnO NPs) are widely used in sunscreen, cosmetics, and topical drugs. Most previous studies have confirmed the safety of ZnO NPs applied to normal skin; however, little is known about the safety and potential toxicity of ZnO NPs applied to inflamed skin. This study aimed to evaluate the exposure risk of ZnO NPs in the treatment of inflammatory skin diseases. METHODS: Normal human and tumor necrosis factor-α (TNF-α)-induced inflammatory keratinocytes were incubated with ZnO NPs to assess their toxic effects on cell viability and autophagy signaling pathway. Tandem mass tag (TMT)-based proteomics analysis was used to identify differentially expressed proteins following incubation of inflammatory keratinocytes with ZnO NPs. Protein expression was assessed by Western blot, and double fluorescent labeling and siRNA-knockdown further elucidated the role of the TRIM16-NRF2-p62 pathway in mediating the effects of ZnO NP. RESULTS: In TNF-α-induced inflammatory keratinocytes, ZnO NPs activated cytoprotective autophagy and mediated p62-related autophagic flux block, thereby reducing the viability of inflammatory keratinocytes. Additionally, TRIM16-NRF2 was essential in ZnO NP-mediated autophagy flux block and cell viability reduction in inflammatory keratinocytes. Inhibition of the TRIM16-NRF2 pathway reduced p62 levels, alleviated autophagy flux blockade, and slightly restored the viability of inflammatory keratinocytes. CONCLUSION: ZnO NPs activated protective cell autophagy. Blockade of autophagy flux mediated by the TRIM16-NRF2-p62 pathway led to decreased cell viability. This study provided a deeper understanding of the toxicity mechanism of ZnO NPs in inflammatory keratinocytes.

Coexistence of Subcutaneous Panniculitis-Like T-Cell Lymphoma and Dermatomyositis in a 12-Year-Old Boy.

Subcutaneous panniculitis-like T-cell lymphoma (SPTL) is an extremely rare, indolent skin malignancy that can be difficult to distinguish from autoimmune disease-associated panniculitides. Here, we describe a 12-year-old boy who was diagnosed at age 7 years with dermatomyositis with classical manifestations, including poikiloderma, Gottron's sign, and symmetric muscle weakness. Recently, the boy presented multiple subcutaneous nodules and fever. Histopathological examination and immunohistochemical staining revealed coexistence of SPTL. To our knowledge, this is the first case of dermatomyositis accompanied with SPTL. This case alert clinical physicians of the possibility of SPTL should be considered when a patient with dermatomyositis has new lesions presenting as nodules and unknown fever.

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.