JCI insight最新文献

Lung development relies on diverse cell intrinsic and extrinsic mechanisms to ensure proper cellular differentiation and compartmentalization. In addition, it requires precise integration of multiple signaling pathways to temporally regulate morphogenesis and appropriate cell specification. To accomplish this, organogenesis relies on epigenetic and transcriptional regulators to promote cell fate and inhibit alternative cell fates. Using genetic mouse and human embryonic stem cell (hESC) differentiation models, tissue explants, and single-cell transcriptomic analysis, we demonstrated that Bromodomain Containing Protein 4 (BRD4) is required for mammalian lung morphogenesis and cell fate. Endodermal deletion of BRD4 impaired epithelial-mesenchymal crosstalk, leading to disrupted proximal-distal patterning and branching morphogenesis. Moreover, temporal deletion of BRD4 revealed developmental stage-specific defects in airway and alveolar epithelial cell specification with a predominant role in proximal airway cell fate. Similarly, BRD4 promoted lung endodermal cell differentiation into airway lineages in a hESC-derived lung organoid model. Together, these data demonstrated that BRD4 orchestrates early lung morphogenesis and separately regulates cell specification, indicating a multifunctional and evolutionarily conserved role for BRD4 in mammalian lung development.

Mutations in LMNA, encoding nuclear lamina protein Lamin A/C, cause premature aging disorders, most notably Hutchinson-Gilford Progeria Syndrome. Despite obvious skull abnormalities in progeroid patients, the disease-causing mechanism remains elusive. The L648R single amino acid substitution blocks prelamin A maturation in mice, modeling a unique human patient. Here, we describe skull deformities in premature aging caused by aberrant suture fusion resembling those of patients with craniosynostosis. Further examinations identify prelamin A accumulation causatively linked to multiple suture synostoses in low bone density. This etiology is distinct from conventional suture fusion mediated by excessive ossification. In addition, the mutation disrupts skeletal stem cell stemness and subsequent stem cell-mediated proliferation and differentiation in osteogenesis. Intrasutural bones present in progeroid patients are highly reminiscent of synostosis caused by stem cell exhaustion. Comparative gene expression profiling further reveals cytoskeletal dynamics associated with skeletogenic cell aging and suture patency in mice and humans. Functional studies demonstrate that abnormal structures of progeric nuclei caused by prelamin A accumulation affect cytoskeleton organization and nucleoskeleton assembly essential for craniofacial skeletogenesis. Pharmacogenetic analyses indicate alleviation of osteogenic defects via actin polymerization. Our findings provide compelling evidence for nuclear and cytoskeletal defects, mediating stem cell-associated osteogenic deformities in progeroid disorders.

Angelman syndrome (AS) is a neurodevelopmental disorder caused by loss of the maternal UBE3A allele, the sole source of UBE3A in mature neurons due to epigenetic silencing of the paternal allele. Although emerging therapies are being developed to restore UBE3A expression by activating the dormant paternal UBE3A allele, existing mouse models for such preclinical studies have limited throughput and utility, creating bottlenecks for both in vitro therapeutic screening and in vivo characterization. To address this, we developed the Ube3a-INSG dual-reporter knock-in mouse, in which an IRES-Nanoluciferase-T2A-Sun1-sfGFP (INSG) cassette was inserted downstream of the endogenous Ube3a stop codon. The INSG model preserves UBE3A protein levels and function while enabling two complementary allele-specific readouts: Sun1-sfGFP and Nanoluciferase. We show that Sun1-sfGFP, a nuclear envelope-localized reporter, enables single-cell fluorescence analysis, whole-brain light-sheet imaging, and nuclear quantification by flow cytometry. Further, Nanoluciferase supports high-throughput luminescence assays for sensitive pharmacological profiling in cultured neurons and non-invasive in vivo bioluminescence imaging for pharmacodynamic assessment. By combining scalable screening, cellular analysis, and real-time in vivo monitoring in a single model, the Ube3a-INSG dual-reporter mouse provides a powerful platform to accelerate therapeutic development centered on UBE3A.

Immunosuppression and metastasis are critical hallmarks of breast cancer, often linked to poor patient outcomes. The secreted cytokine chitinase-3 like 1 (CHI3L11) is frequently overexpressed in breast cancer samples and promotes an immunosuppressed tumor microenvironment. Notably, CHI3L1 expression is elevated in metastatic patient samples when compared to the matched primary breast tumor. To investigate its role in breast cancer metastasis, we generated an inducible Genetically Engineered Mouse Model (GEMM) that overexpresses CHI3L1 in the mammary epithelium. Ectopic expression of CHI3L1 in the Polyomavirus Middle T (PyMT) mouse model of breast cancer suppressed anti-tumor immune responses, accelerated mammary tumor onset and enhanced lung metastasis. Mechanistically, elevated CHI3L1 expression in the mammary epithelium enhanced neutrophil recruitment, which subsequently degraded the extracellular matrix and increased the number of circulating tumor cells. These findings reveal a key mechanism driving metastatic dissemination and argue that therapeutically targeting Chi3l1 could enhance anti-tumor immunity and suppress metastasis.

Chronic hyperglycemia changes the expression of various transcription factors and mRNA transcripts, which impair the cellular functionality and delayed wound healing. ZEB2 (zinc finger E-box binding homeobox 2), a key transcription factor maintains the tissue specific macrophage identities, however, its role in regulating macrophage polarization during wound healing under hyperglycemic conditions remains unclear. Here, we have found that persistent hyperglycemia increases ZEB2 expression in wound macrophages via histone acetylation, contributing to chronic inflammation, and delayed wound healing. Exposure to high glucose levels activates P300/CBP, a transcriptional coactivator involved in histone acetylation, enhances ZEB2 expression in wound macrophages. The forced expression of ZEB2 shifts macrophage polarity toward a pro-inflammatory state by upregulating myeloid lineage directed transcription factors (MLDTFs). Conversely, silencing Zeb2 at the wound site reduced hyperglycemia induced macrophage inflammation. Topical application of C646, an inhibitor of P300, at the wound edges of streptozotocin induced high-fat diet fed diabetic mice significantly decreased ZEB2 expression, reduced inflammation and accelerated wound healing. Therefore, targeted inhibition of P300 represents a promising therapeutic strategy for improving diabetic wound healing by modulating ZEB2 driven inflammation in wound macrophages.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by immune dysregulation and widespread inflammation. Natural killer (NK) cells display marked functional impairment in SLE, including defective cytotoxicity and cytokine production, but the underlying mechanisms remain poorly defined. Here, we show that mitochondrial dysfunction and impaired mitophagy are key contributors to NK cell abnormalities in SLE. Using complementary structural, metabolic, and proteomic analyses, we found that SLE NK cells accumulate enlarged and dysfunctional mitochondria, exhibit impaired lysosomal acidification, and release mitochondrial DNA into the cytosol-features consistent with defective mitochondrial quality control. Transcriptional and proteomic profiling revealed downregulation of key mitophagy-related genes and pathways. These abnormalities correlated with reduced NK cell degranulation and cytokine production. We then tested whether enhancing mitochondrial quality control could restore NK cell function. The mitophagy activator Urolithin A improved mitochondrial and lysosomal parameters and rescued NK cell effector responses in vitro. Hydroxychloroquine partially restored mitochondrial recycling and reduced cytosolic mtDNA. These findings suggest that defective mitophagy and mitochondrial dysfunction are major contributors to NK cell impairment in SLE and that targeting mitochondrial quality control may represent a promising strategy for restoring immune balance in this disease.

Psoriasis is a chronic inflammatory dermatosis characterized by pathological keratinocyte hyperproliferation and dysregulated immune activation. While ubiquitin-specific peptidase 16 (USP16) has been implicated in modulating multiple cellular signaling pathways, its functional role in psoriatic pathogenesis remains poorly understood. Our investigation revealed pronounced upregulation of USP16 expression in psoriatic epidermis compared to normal controls. Keratinocyte-specific USP16 knockdown demonstrated remarkable therapeutic efficacy, significantly ameliorating characteristic psoriatic phenotypes including epidermal hyperplasia and inflammatory infiltration. RNA sequencing analysis showed that USP16 has substantial effects on cell cycle transition and keratinocytes proliferation. Through KEGG analysis, it was found that USP16 primarily regulates the NLRP3 signaling pathway, leading to enhanced cell proliferation and inflammation. Mechanically, USP16 directly binds to the NLRP3 protein to eliminate K48 ubiquitination modification, enhancing the stability of the NLRP3 protein, activating inflammasome activity. Further studies showed that the therapeutic effect of reducing USP16 on psoriasis progression were counteracted by an NLRP3 activator and keratinocyte-specific NLRP3 overexpression adenovirus. Collectively, these results shed light on how USP16 promotes NLRP3 signaling in keratinocytes, exacerbating psoriasis development. This positive regulation highlights the potential of USP16 as a therapeutic target for psoriasis.

Alveolar hemorrhage (AH) is a life-threatening condition with high mortality, yet the immunologic mechanisms governing disease severity remain poorly defined. Here, we demonstrate a protective role for T cell-intrinsic β-catenin stabilization in AH using a transgenic mouse model (CAT-Tg) in which β-catenin is stabilized under the Lck promoter. β-Catenin stabilization induced a distinct T cell phenotype marked by expansion of central effector memory cells (CD44+CD122+Eomes+T-bet+) and suppression of proinflammatory signaling, including reduced phosphorylation of STAT1, STAT3, and JAK1. Pristane-induced AH was attenuated in CAT-Tg mice, which exhibited reduced lung injury, decreased proteinuria, and diminished pulmonary proinflammatory cytokine production compared with wild-type controls. Protection was associated with a marked expansion of FOXP3+ regulatory T cells (Tregs). Mechanistically, β-catenin stabilization enhanced lung expression of Amphiregulin and BATF, mediators of Treg stability and tissue repair. Adoptive transfer of CAT-Tg-derived Tregs into wild-type mice conferred superior protection against AH, reducing lung inflammation and proteinuria. Transcriptomic analyses revealed enrichment of tissue repair and immune homeostasis pathways, including PI3K-Akt, angiogenesis, and STAT5 signaling. Collectively, these findings identify β-catenin as a regulator of a protective Amphiregulin-BATF-Treg axis, highlighting a immunomodulatory pathway with therapeutic potential for AH and inflammatory lung disease.

We provide evidence that human and murine SLFN5 proteins are modulators of Type I IFN responses and the immune response in pancreatic cancer. Blocking expression of Slfn5 in PDAC enhances IFN-responses, suppresses tumor growth, and prolongs survival in immunocompetent mice. Notably, immunophenotypic analysis reveals a reduction in tumor-associated macrophages (TAMs) alongside an increase in tumor infiltrating effector cells in tumors over time. These findings implicate SLFN5 acts as an intracellular immune checkpoint and identify it as a unique therapeutic target for the development of therapies for PDAC and possibly other malignancies.