Project description:We isolated dysfunctional splenic NK cells in mice with melanoma metastasis and performed bulk RNA-seq with the NK cells to explore the mechanism of NK cell dysfunction with a special focus on signaling pathway linked to NK cell cytotoxicity.
Project description:Objectives: Natural Killer (NK) cell dysfunction contributes to systemic lupus erythematosus (SLE) pathogenesis, but its underlying mechanisms remain poorly understood. This study investigates immunometabolic alterations in NK cells from SLE patients and explores therapeutic strategies for their restoration. Methods: We characterized mitochondrial structure and function in NK cells from the peripheral blood of SLE patients and healthy controls using flow cytometry, electron microscopy, and proteomics. Key mitophagy-related gene expressions were quantified using qPCR. The therapeutic effects of hydroxychloroquine (HCQ) on mitochondrial recycling and NK cell function were assessed in vitro. Results: SLE NK cells were characterized by an accumulation of enlarged, hyperpolarized mitochondria with cristae disorganization, and reduced mitophagy. Impaired lysosomal acidification and mtDNA extrusion into the cytosol were also observed. Treatment with hydroxychloroquine restored lysosomal pH, mitochondrial recycling, and NK cell effector functions, including cytokine production and cytotoxicity. Conclusions: This study identifies mitochondrial recycling dysfunction as a driver of NK cell abnormalities in SLE and highlights the potential of HCQ to restore NK cell functionality. These findings provide new insights into the immunometabolic mechanisms underlying SLE and suggest avenues for targeted therapeutic interventions.
Project description:Natural killer (NK) cells are central to innate antitumor immunity, yet their function is systemically compromised in colorectal cancer (CRC). We show that CRC patients exhibit early and pronounced alterations in peripheral blood NK cells, marked by a reduced frequency of total CD56⁺ cells, a shift toward CD56lowCD16⁺ subset, and impaired cytotoxic and cytokine responses. Notably, plasma from CRC patients, particularly those with advanced disease, induces similar dysfunction in healthy donor (HD) NK cells, suppressing mTORC1 signaling and effector activity. Transcriptomic profiling of HD NK cells exposed to CRC plasma revealed downregulation of TNF-α signaling components, concordant with reduced systemic and intracellular TNF-α levels in patients. Additionally, CRC plasma suppressed the JAK-STAT pathway and upregulated SOCS family genes, further dampening NK cell responsiveness. Inhibition of TNF-α in HD NK cells recapitulated the CRC plasma–induced defects, while exogenous TNF-α partially restored NK cell function, including STAT5 and S6 phosphorylation. These findings uncover TNF-α signaling deficiency as a systemic mechanism of NK cell suppression in CRC, linking impaired metabolism to immune evasion. Targeting this axis may offer a novel strategy to reinvigorate NK cell–mediated antitumor immunity in CRC.
Project description:Natural killer (NK) cells contribute to immunosurveillance and first-line defense in the control of tumor growth and metastasis diffusion. NKEVs are constitutively secreted, are biologically active, reflect the protein and genetic repertoire of their originating cells and exert anti-tumor activity in vitro and in vivo. NKEVs from tumor-conditioned NK cells interact with naïve NK cells promoting their cytotoxic activity. In cancer NK cells exhibit profound defects in degranulation ability, a status probably reflected by their NKEVs. Hence, NKEVs could contribute to improve cancer therapy by interacting with tumor and/or immune cells at the same time sensing the actual NK cell status in cancer patients. Here we investigated the role of NKEVs in stimulating the immune system and developed an immune enzymatic test (NKExoELISA) to sense the systemic NK cell status by measuring plasma NK-derived exosomes through combined capture of exosomes, expressing typical EV (tsg101) and NK cell (CD56) markers. We analyzed by LC-MS/MS the protein content from NKEVs evaluating proteins differentially expressed in exosomes (NKExo), vescicles (NKMV) and total cell extract (Tot extr) from parental NK cells. Proteomic data confirmed the presence of many EV markers and detected several proteins involved in immune response, cell adhesion and complement biological processes.
Project description:In order to gain a better understanding of gene expression during early malaria infection, we conducted microarray analysis of early blood responses in mice infected with erythrocytic stage Plasmodium chabaudi. Immediately following infection, we observed coordinated and sequential waves of immune responses, with interferon-associated gene transcripts dominating by 16 hours post-infection, followed by strong increases in natural killer (NK) cell-associated and MHC class I-related transcripts by 32 hours post-infection. We hypothesized that the observed elevation in NK cell-associated transcripts could be the result of a dramatic increase in the proportion of NK cells in the blood during infection, which we confirmed by flow cytometry. Subsequent microarray analysis of NK cells isolated from the peripheral blood of infected mice revealed a cell proliferation expression signature consistent with the observation that NK cells replicate in response to infection. Early proliferation of NK cells was directly observed in studies with adoptively transferred cells in infected mice. These data indicate that the early response to P. chabaudi infection of the blood is marked by a primary wave of interferon with a subsequent response by NK cells. Keywords: murine NK cell response to Plasmodium chabaudi infection We analyzed a series of 10 MEEBO arrays on which were hybed RNA amplified from NK cells of C57BL/6 mice either mock-infected or infected with P. chabaudi AS.
Project description:Breast cancer metastasis to bone is a critical determinant of long-term survival after treatment of primary tumors. We used a mouse model of spontaneous bone metastasis to determine new molecular mechanisms. Differential transcriptome comparisons of primary and metastatic tumor cells revealed that a substantial set of genes suppressed in bone metastases were highly enriched for promoter elements for the type I interferon (IFN) regulatory factor, Irf7, itself suppressed in mouse and human metastases. The critical function of the Irf7 pathway was demonstrated by restoration of exogenous Irf7 or systemic interferon administration, which significantly reduced bone metastases and prolonged metastasis-free survival. Using mice deficient in the type I receptor (Ifnar1-/-) or mature B, T and NK cell responses (NOD Scid IL-2rγ-/- mice), we demonstrated that Irf7-driven suppression of metastasis was reliant on IFN signaling to host immune cells. Metastasis suppression correlated with decreased accumulation of myeloid-derived suppressor cells and increased CD4++, CD8 T cells and NK cells in the peripheral blood and was reversed by depletion of CD8+ cells and NK cells. Clinical importance of our findings was demonstrated as increased primary tumor Irf7 expression predicted prolonged bone and lung metastasis-free survival. Thus we report for the first time, a novel innate immune pathway, intrinsic to breast cancer cells, whose suppression in turn restricts systemic immunosurveillance to enable metastasis. This pathway may constitute a novel therapeutic target for restricting breast cancer metastases. Microarrays were used to profile transcriptional alterations inherent in tumor cells growing in bone when compared to matched primary tumor cells in the 4T1.2 murine mammary tumor model. Primary and metastasized tumor were isolated from the same mouse with 4 independent biological replicates.
Project description:Cancer-induced tolerance mostly involves myeloid suppressor cells, regulatory T cells and immunosuppressive cytokines, which all subvert adaptive immune responses against tumor cells. Here, we show that a subset of innate effectors, c-kit expressing NK cells (Kit+ NK), can participate in tumor-induced tolerance by compromising the NK cell arm of tumor immunosurveillance. IL-18 produced by tumor cells can convert Kit- into Kit+ NK cells that overexpress B7-H1/PD-L1 molecules. Upon tumor inoculation, Kit+ NK cells rapidly develop in lymphoid organs in a IL-18R/MyD88 dependent manner and directly kill Kit- NK cells in a B7-H1/PD-1-dependent manner, thereby promoting the progression of NK-controlled cancers. Our data suggest that, in a tumoral context, IL-18 subverts antitumor NK cell functions. Systemic neutralization of IL-18 by IL-18-binding protein may improve the NK-mediated immunosurveillance. Keywords: cell type comparison
Project description:Somatic STAT5B gain-of-function mutations have been frequently found in patients with T- and NK-cell neoplasms. STAT5BN642H represents the most frequently occuring STAT5B mutation. To investigate the molecular mechanism of STAT5BN642H-driven NK-cell leukemia, we performed RNA-Seq of liver derived FACS-sorted diseased N642HNK/NK and aged non-diseased control (Cre neg, GFPNK/NK), STAT5BNK/NK, N642HNK/NK NK cells.