Journal of Clinical Investigation最新文献

The persistent emergence of COVID-19 variants and recurrent waves of infection worldwide underscores the urgent need for vaccines that effectively reduce viral transmission and prevent infections. Current intramuscular (IM) COVID-19 vaccines inadequately protect the upper respiratory mucosa. In response, we have developed a nonadjuvanted, interferon-armed SARS-CoV-2 fusion protein vaccine with IM priming and intranasal (IN) boost sequential immunization. Our study showed that this sequential vaccination strategy of the IM+IN significantly enhances both upper respiratory and systemic antiviral immunity in a mouse model, characterized by the rapid increase in systemic and mucosal T and B cell responses, particularly the mucosal IgA antibody response. The IN boost triggered a swift secondary immune response, rapidly inducing antigen-specific IgA+ B cells. Further BCR-seq analysis indicated that these IgA+ B cells primarily arise through direct class switching from pre-existing IgG+ B cells in draining lymph nodes. Notably, our clinical studies reveal that the IN boost after IM vaccination elicited a robust systemic IgA antibody response in humans, as measured in serum. Thus, our cytokine-armed protein vaccine presents a promising strategy for inducing rapid and potent mucosal protection against respiratory viral infections.

Radiotherapy can be limited by pneumonitis which is impacted by innate immunity, including pathways regulated by TRAIL death receptor DR5. We investigated whether DR5 agonists could rescue mice from toxic effects of radiation and found two different agonists, parenteral PEGylated trimeric-TRAIL (TLY012) and oral TRAIL-Inducing Compound (TIC10/ONC201) could reduce pneumonitis, alveolar-wall thickness, and oxygen desaturation. Lung protection extended to late effects of radiation including less fibrosis at 22-weeks in TLY012-rescued survivors versus un-rescued surviving irradiated-mice. Wild-type orthotopic breast tumor-bearing mice receiving 20-Gy thoracic radiation were protected from pneumonitis with disappearance of tumors. At the molecular level, radioprotection appeared due to inhibition of CCL22, a macrophage-derived chemokine previously associated with radiation pneumonitis and pulmonary fibrosis. Treatment with anti-CCL22 reduced lung injury in vivo but less so than TLY012. Pneumonitis severity was worse in female versus male mice, and this was associated with increased expression of X-linked TLR7. Irradiated mice had reduced esophagitis characterized by reduced epithelial disruption and muscularis externa thickness following treatment with ONC201 analogue ONC212. The discovery that short-term treatment with TRAIL pathway agonists effectively rescues animals from pneumonitis, dermatitis and esophagitis following high doses of thoracic radiation exposure has important translational implications.

Eccentric contraction- (ECC) induced force loss is a hallmark of murine dystrophin-deficient (mdx) skeletal muscle that is used to assess efficacy of potential therapies for Duchenne muscular dystrophy. While virtually all key proteins involved in muscle contraction have been implicated in ECC force loss, a unifying mechanism that orchestrates force loss across such diverse molecular targets has not been identified. We showed that correcting defective hydrogen sulfide (H2S) signaling in mdx muscle prevented ECC force loss. We also showed that the cysteine proteome of skeletal muscle functioned as a redox buffer in WT and mdx muscle during ECCs, but that buffer capacity in mdx muscle was significantly compromised by elevated basal protein oxidation. Finally, chemo-proteomic data suggested that H2S protected several proteins central to muscle contraction against irreversible oxidation through persulfidation-based priming. Our results support a unifying, redox-based mechanism of ECC force loss in mdx muscle.

Hematopoietic stem cells (HSCs) rely on self-renewal to sustain stem cell potential and undergo differentiation to generate mature blood cells. Mitochondrial fatty acid β-oxidation (FAO) is essential for HSC maintenance. However, the role of Carnitine palmitoyl transferase 1a (CPT1A), a key enzyme in FAO, remains unclear in HSCs. Using a Cpt1a hematopoietic specific conditional knock-out (Cpt1aΔ/Δ) mouse model, we found that loss of Cpt1a leads to HSC defects, including loss of HSC quiescence and self-renewal, and increased differentiation. Mechanistically, we find that loss of Cpt1a results in elevated levels of mitochondrial respiratory chain complex components and their activities, as well as increased ATP production, and accumulation of mitochondrial reactive oxygen species (mitoROS) in HSCs. Taken together, this suggests hyperactivation of mitochondria and metabolic rewiring via upregulated glucose-fueled oxidative phosphorylation (OXPHOS). In summary, our findings demonstrate a novel role for Cpt1a in HSC maintenance and provide insight into the regulation of mitochondrial metabolism via control of the balance between FAO and glucose-fueled OXPHOS.

Tumor-initiating cells (TICs) play a key role in cancer progression and immune escape. However, how TICs evade immune elimination remains poorly characterized. Combining single-cell RNA sequencing (scRNA-seq), dual-recombinase-based lineage tracing, and other approaches, we identified a WNT-activated subpopulation of malignant cells that act as TICs in vivo. We found intensive reciprocal interactions between TICs and immune regulatory tumor-associated macrophages (Reg-TAMs) via GAS6-AXL/MERTK signaling pathways, which facilitated the immune escape of TICs. Our study employed chemical inhibitors and Axl/Mertk conditional double knockout mice to demonstrate that inhibiting the interaction between TIC-derived GAS6 and AXL/MERTK in Reg-TAMs reactivated anti-tumor immune responses. We identified CCL8 as a critical mediator of the GAS6/AXL/MERTK pathway, primarily by inhibiting regulatory T cell (Treg) infiltration into the tumor. Furthermore, the AXL/MERTK signaling blockade sensitized tumor cells to anti-PD-1 treatment. Thus, we elucidated a detailed mechanism by which TICs evade tumor immunity, providing insights into strategies to eradicate TICs that escape conventional immunotherapy.

Neutrophils, particularly low-density neutrophils (LDNs), are believed to contribute to acute COVID-19 severity. Here, we showed that neutrophilia can be detected acutely and even months after SARS-CoV-2 infection in patients and mice, while neutrophil depletion reduced disease severity in mice. A key factor in neutrophilia and severe disease in infected mice was traced to the chemokine CXCL12 secreted by bone marrow cells and unexpectedly, endothelial cells. CXCL12 levels were negatively correlated with LDN numbers in longitudinal analyses of patient blood samples. CXCL12 blockade in SARS-CoV-2-infected mice increased blood/lung neutrophil numbers, thereby accelerating disease progression without changing lung virus titers. The exaggerated mortality caused by CXCL12 blockade could be reversed by neutrophil depletion. In addition, blocking interactions between SARS-CoV-2 and angiotensin-converting enzyme 2 (ACE2) reduced CXCL12 levels, suggesting a signal transduction from virus-mediated ACE2 ligation to increased CXCL12 secretion. Collectively, these results demonstrate a previously unappreciated role of CXCL12 in diminishing neutrophilia, including low-density neutrophilia, and its deleterious effects in SARS-CoV-2 infections. The results also support the involvement of SARS-CoV-2-endothelial cell interactions in viral pathogenesis.

BACKGROUNDMyotonic dystrophy type 1 (DM1) is a multisystemic, CTG repeat expansion disorder characterized by a slow, progressive decline in skeletal muscle function. A biomarker correlating RNA mis-splicing, the core pathogenic disease mechanism, and muscle performance is crucial for assessing response to disease-modifying interventions. We evaluated the Myotonic Dystrophy Splice Index (SI), a composite RNA splicing biomarker incorporating 22 disease-specific events, as a potential biomarker of DM1 muscle weakness.METHODSTotal RNA sequencing of tibialis anterior biopsies from 58 DM1 participants and 33 unaffected/disease controls was used to evaluate RNA splicing events across the disease spectrum. Targeted RNA sequencing was used to derive the SI from biopsies collected at baseline (n = 52) or a 3-month (n = 37) follow-up visit along with clinical measures of muscle performance.RESULTSThe SI demonstrated significant associations with measures of muscle strength and ambulation, including ankle dorsiflexion (ADF) strength and 10-meter run/fast walk (Pearson's r = -0.719 and -0.680, respectively). The SI was relatively stable over 3 months (intraclass correlation coefficient [ICC] = 0.863). Latent-class analysis identified 3 DM1 subgroups stratified by baseline SI (SIMild, SIModerate, and SISevere); SIModerate individuals had a significant increase in the SI over 3 months. Multiple linear regression modeling revealed that baseline ADF and SI were predictive of strength at 3 months (adjusted R² = 0.830).CONCLUSIONThe SI is a reliable biomarker that captures associations of RNA mis-splicing with physical strength and mobility and has prognostic utility to predict future function, establishing it as a potential biomarker for assessment of therapeutic target engagement.TRIAL REGISTRATIONClinicalTrials.gov NCT03981575.FUNDINGFDA (7R01FD006071), Myotonic Dystrophy Foundation, Wyck Foundation, Muscular Dystrophy Association, Novartis, Dyne, Avidity, PepGen, Takeda, Sanofi Genzyme, Pfizer, Arthex, and Vertex Pharmaceuticals.

Nasopharyngeal carcinoma (NPC) presents a substantial clinical challenge due to the limited understanding of its genetic underpinnings. Here we conduct the largest scale whole-exome sequencing association study of NPC to date, encompassing 6,969 NPC cases and 7,100 controls. We unveil 3 germline genetic variants linked to NPC susceptibility: a common rs2276868 in RPL14, a rare rs5361 in SELE, and a common rs1050462 in HLA-B. We also underscore the critical impact of rare genetic variants on NPC heritability and introduce a refined composite polygenic risk score (rcPRS), which outperforms existing models in predicting NPC risk. Importantly, we reveal that the polygenic risk for NPC is mediated by EBV infection status. Utilizing a comprehensive multiomics approach that integrates both bulk-transcriptomic (n = 356) and single-cell RNA sequencing (n = 56) data with experimental validations, we demonstrate that the RPL14 variant modulates the EBV life cycle and NPC pathogenesis. Furthermore, our data indicate that the SELE variant contributes to modifying endothelial cell function, thereby facilitating NPC progression. Collectively, our study provides crucial insights into the intricate genetic architecture of NPC, spotlighting the vital interplay between genetic variations and tumor microenvironment components, including EBV and endothelial cells, in predisposing to NPC. This study opens new avenues for advancements in personalized risk assessments, early diagnosis, and targeted therapies for NPC.

Clonal hematopoiesis (CH) is a condition in which hematopoietic stem cells (HSCs) acquire mutations seen in leukemia. While individuals with CH generally do not show signs of hematologic disease, the condition becomes more common with age and correlates with age-related diseases, especially cardiovascular disease (CVD). JAK2 mutations in HSCs can lead to CH and correlate with atherosclerosis, but the condition has been difficult to study because of challenges modeling the mutant cells at very low frequency. In this issue of the JCI, Liu et al. developed a low-allele-burden (LAB) mouse model in which a small number of bone marrow cells carrying the Jak2VF mutation were transplanted into mice predisposed to hyperlipidemia. Along with recapitulating features of plaque development, the authors identified the phagocytic receptors MERTK and TREM2 in WT cells as downstream of the inflammatory cytokine IL-1. These findings provide potential targets for preventing or treating patients at risk for CH-associated CVD.