Role Of Receptor-interacting Protein Kinase 3 Research Articles

Receptor-interacting protein kinase-3 (RIPK3): a new biomarker for necrotising enterocolitis in preterm infants

ObjectiveThis study aimed to evaluate the role of receptor-interacting protein kinase-3 (RIPK3) in the diagnosis, estimation of disease severity, and prognosis of premature infants with necrotising enterocolitis (NEC).MethodsRIPK3, lactic acid (LA), and C-reactive protein (CRP) levels were measured in the peripheral blood of 108 premature infants between 2019 and 2023, including 24 with stage II NEC, 18 with stage III NEC and 66 controls. Diagnostic values of the indicators for NEC were evaluated via receiver operating characteristic (ROC) curve analysis.ResultsPlasma RIPK3 and LA levels upon NEC suspicion in neonates with stage III NEC were 32.37 ± 16.20 ng/mL. The ROC curve for the combination of RIPK3, LA, CRP for NEC diagnosis were 0.925. The time to full enteral feeding (FEFt) after recovery from NEC was different between two expression groups of plasma RIPK3 (RIPK3 < 20.06 ng/mL and RIPK3 ≥ 20.06 ng/mL).ConclusionPlasma RIPK3 can be used as a promising marker for the diagnosis and estimation of disease severity of premature infants with NEC and for the guidance on proper feeding strategies after recovery from NEC.

369-OR: Defining the Role of RIPK3 in Beta Cells and the Mechanism of Its Activation by ER Stress

Receptor interacting protein kinase 3 (RIPK3) can activate and be activated by ER stress. Islet inflammation associated with underlying activation of RIPK3 is conserved from zebrafish to humans. However, the role of RIPK3 in mammalian beta cells and the mechanism by which ER stress activates RIPK3 are not well defined. To investigate the role of RIPK3 in beta cell function, we generated beta cell specific Ripk3 knockout mice (Ripk3ßKO) in C57BL/6J background with or without the Akita mutation (Ins2C96Y/+, which causes ER stress induced beta cell apoptosis and early onset diabetes) (Ripk3ßKOAkita) . We found that the glucose tolerance was worsened in Ripk3ßKO mice than wildtype controls after 16 weeks of high fat diet. Similarly, Ripk3ßKOAkita mice had higher random blood glucose, lower circulating insulin, and worse glucose tolerance than Akita C57BL/6J mice as early as 4 weeks of age. Unexpectedly, isolated islets from Ripk3ßKO and Ripk3ßKOAkita mice have comparable glucose stimulated insulin secretion (GSIS) and are more resilient to palmitate-induced lipotoxicity than their control counterparts. Similarly, pharmacological inhibition of RIPK3 protected human islets from palmitate-induced impairment of GSIS ex vivo. We are currently investigating the role of specific islet inflammation stages in the divergent GSIS phenotypes between in vivo and ex vivo. To investigate how ER stress activates RIPK3 in beta cells, we tested the effect of inhibiting classic UPR branches on RIPK3 activation in MIN6 cells, a mouse beta cell line. We found that IRE1a activation appears to play an essential role in RIPK3 activation. Interestingly, Ripk3 knockdown in MIN6 cells also decreased IRE1a levels. We next seek to define the mechanism underlying the crosstalk between RIPK3 and IRE1a signaling pathways. Disclosure L.Yang: None. B.Yang: None. X.Tong: None. C.Dai: None. Z.Tang: None. W.Chen: None. Funding National Institutes of Health (DK117147)

RIPK3 blockade attenuates tubulointerstitial fibrosis in a mouse model of diabetic nephropathy

Receptor-interacting protein kinase-3 (RIPK3) is a multifunctional regulator of cell death and inflammation. RIPK3 controls cellular signalling through the formation of the domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, which is recognised to mediate renal fibrogenesis. The role of RIPK3 in diabetic kidney disease (DKD) induced renal fibrosis has not been previously determined. To define the action of RIPK3 in the development of diabetic kidney disease, wild-type (WT), RIPK3 -/- and endothelium-derived nitric oxide synthase (eNOS)-/- mice were induced to develop diabetes mellitus using multiple low doses of streptozotocin and maintained for 24 weeks. RIPK3 activity and NLRP3 expression were upregulated and fibrotic responses were increased in the kidney cortex of WT mice with established diabetic nephropathy compared to control mice. Consistently, mRNA expression of inflammasome components, as well as transforming growth factor beta 1 (TGFβ1), α smooth muscle actin (α-SMA) and collagen deposition were increased in diabetic kidneys of WT mice compared to control mice. However, these markers were normalised or significantly reversed in kidneys of diabetic RIPK3 -/- mice. Renoprotection was also observed using the RIPK3 inhibitor dabrafenib in eNOS-/- diabetic mice as demonstrated by reduced collagen deposition and myofibroblast activation. These results suggest that RIPK3 is associated with the development of renal fibrosis in DKD due to the activation of the NLRP3 inflammasome. Inhibition of RIPK3 results in renoprotection. Thus, RIPK3 may be a potential target for therapeutic intervention in patients with diabetic kidney disease.

Is Receptor-Interacting Protein Kinase 3 a Viable Therapeutic Target for Mycobacterium tuberculosis Infection?

The dwindling list of antimicrobial agents exhibiting broad efficacy against clinical strains of Mycobacterium tuberculosis (Mtb) has forced the medical community to redefine current approaches to the treatment of tuberculosis (TB). Host receptor-interacting protein kinase 3 (RIPK3) has been flagged recently as a potential target, given that it is believed to regulate necroptosis-independent signaling pathways, which have been implicated in exacerbating several inflammatory conditions and which reportedly play a role in the necrosis of Mtb-infected macrophages. To examine the therapeutic potential of inhibiting RIPK3, we infected RIPK3-deficient mice with aerosolized Mtb. We found that the loss of RIPK3 did not alter overall disease outcomes, with deficient animals harboring similar bacterial numbers in the lungs and spleens compared to their wild-type counterparts. Mtb-infected macrophages were not rescued from dying by Ripk3 deletion, nor did this affect production of the pro-inflammatory cytokine IL-1β, both in vitro and in vivo. Infiltration of immune cells into the lungs, as well as the activation of adaptive immunity, similarly was not overtly affected by the loss of RIPK3 signaling. Collectively, our data argue against a role of RIPK3 in mediating pathological inflammation or macrophage necrosis during Mtb disease pathogenesis and thus suggest that this host protein is unlikely to be an attractive therapeutic target for TB.

Down-regulation of RIP3 potentiates cisplatin chemoresistance by triggering HSP90-ERK pathway mediated DNA repair in esophageal squamous cell carcinoma

Receptor interacting protein kinase 3 (RIP3) is a critical regulator of programmed necrotic cell death. Here, we observed that RIP3 was significantly down-regulated in esophageal cancer. And its remaining expression was associated with better response to chemotherapy and prolonged survival. Notably, re-expression of kinase-dead RIP3 also restored cisplatin sensitivity, suggesting that some roles of RIP3 beyond necroptosis may be involved in cisplatin-based chemosensitivity. To investigate the mechanisms, a large-scale quantitative proteomics study was performed after cisplatin treatment in RIP3-knockdown cells. In total, approximately 7000 protein groups were confidently identified, with a false discovery rate of 0.21% at the protein level. Of these proteins, 685 displayed RIP3-dependent changes in abundance. Bioinformatics analyses indicated that DNA repair pathway was stimulated after RIP3 depletion. Functional studies showed that deficient RIP3 upregulated FOSL1 and POLD1 through activation of the HSP90/CDC37 complex and ERK phosphorylation in multiple cell lines. Furthermore, via inhibition of the HSP90/CDC37 complex, ERK and FOSL1 reversed the cisplatin resistance phenotype. These results suggest that RIP3 regulates cisplatin sensitivity through both pronecrotic and non-necrotic functions. RIP3 may be a potential marker for predicting chemosensitivity.

Border Security: The Role of RIPK3 in Epithelium Homeostasis.

Receptor interacting protein kinase 3 (RIPK3) is a crucial inducer of necroptosis. Its activity is controlled by interaction with other signal adaptors through the “RIP homotypic interaction motif” (RHIM). Recent studies revealed a critical function for RIPK3 in the maintenance of epithelial tissue integrity. In mice with genetic deficiency of the apoptosis adaptors FADD or caspase 8, RIPK3 promotes necroptotic cell death of epithelial cells, leading to excessive and lethal inflammation. In contrast, when FADD and caspase 8 functions are intact, RIPK3 serves as a protector of intestinal epithelial integrity by promoting injury-induced wound repair. In the latter case, RIPK3 promotes optimal cytokine expression by cells of hematopoietic origin. Specifically, bone marrow derived dendritic cells (BMDCs) have an obligate requirement for RIPK3 for optimal secretion of mature IL-1β and other inflammatory cytokines in response to toll-like receptor 4 (TLR4) stimulation. RIPK3 promotes cytokine expression through two complementary mechanisms: NF-κB dependent gene transcription and processing of pro-IL-1β. We propose that RIPK3 functions in different cell compartments to mediate inflammation through distinct mechanisms.

Receptor-interacting protein kinase 3 is apredictor of survival and plays atumor suppressive role in colorectal cancer.

Receptor-interacting protein kinase 3 (RIP3) is amember of the RIP Ser/Thr kinase family, plays an important role in regulating cell survival, cell apoptosis and cell necrosis. However, the role of RIP3 in the carcinogenesis of colorectal cancer is still poorly understood.We used quantitative PCR and Western blot analysis to examine RIP3 expression in primary colorectal cancer and paired normal colorectal mucosa. RIP3 clinicopathological significance was assessed by immunohistochemical staining in 112 cases of primary colorectal cancer paired with noncancerous tissues. The biological function of RIP3 overexpression was measured by CCK8 assay and plate colony formation assay. Dual staining with fluorescent Annexin Vand propidium iodide (PI) was used to discriminate apoptotic or necrotic cell death.RIP3 expression was significantly lower in colorectal cancer and associated with Tstage, Mstage and AJCC stage. Cox proportional hazard models showed that RIP3 expression was an independent prognostic factor for overall survival and disease-free survival in patients with colorectal cancer. Overexpression of RIP3 significantly suppressed the proliferation of colorectal cancer cells in vitro.Our results suggest that RIP3 may function as anovel prognostic indicator after surgery and play asuppressive role in the colorectal carcinogenesis.

Abstract 1342: RIP3 is downregulated in human myeloid leukemia cells and modulates apoptosis and caspase-mediated p65/RelA cleavage

Abstract Introduction. Impairment in cell death pathways represents a general characteristic of most cancer cells. The receptor-interacting protein kinase 3 (RIP3) associates with RIP1 in a necrosome complex that can induce necroptosis, apoptosis, or cell proliferation. The role of RIP3 in necroptosis and inflammation has been extensively studied, but its role in cancer remains poorly understood Methods. We analyzed the expression of RIP1 and RIP3 in CD34+ leukemia cells from a cohort of patients with acute myeloid leukemia (AML) and CD34+ cells from healthy donors. To analyze the potential advantages for myeloid malignant cells due to reduced RIP3 expression, we induced the expression of RIP3 in the DA1-3b mouse leukemia cell line. Results. RIP3 expression was significantly reduced in most AML samples, whereas the expression of RIP1 did not differ significantly. When re-expressed in the mouse DA1-3b leukemia cell line, RIP3 induced apoptosis, and necroptosis in the presence of caspase inhibitors. Surprisingly, the re-expression of a RIP3 mutant with an inactive kinase domain (RIP3-KD) induced significantly more and earlier apoptosis than wild-type RIP3 (RIP3 WT), indicating that the RIP3 kinase domain is an essential regulator of apoptosis/necroptosis in leukemia cells. The induced in vivo expression of RIP3-KD, but not RIP3 WT prolonged the survival of mice injected with leukemia cells. RIP3-KD-induced cell death but not RIP3 WT was significantly antagonized by an IKKβSSEE constitutively active mutant, showing that RIP3-KD-induced apoptosis, but not RIP3 WT-induced apoptosis, was dependent on NF-κB activity. The expression of RIP3-KD induced p65/RelA NF-κB subunit caspase-dependent cleavage, and a non-cleavable p65/RelA D361E mutant rescued cells from apoptosis. The protective effect of the p65/RelA D361E mutant against apoptosis was specific to RIP3-KD-induced cell death because no change in cell death was observed when apoptosis was instead induced by treatment with imatinib or DMSO. The p65/RelA D361E mutant was generated by mutating the INFD putative consensus recognition site for caspase-6. The caspase-6 inhibitor Z-VEID-fmk partially reduced the cell death induced by RIP3-KD and slightly reduced p65/RelA cleavage. p65/RelA cleavage appears to be at least partially mediated by caspase-6. Conclusions. These data indicate that RIP3 silencing in leukemia cells results in suppression of the complex regulation of the apoptosis/necroptosis switch and the modulation of the NF-κB pathway through the caspase-mediated cleavage of p65/RelA. Citation Format: Anne-Lucie Nugues, Hassiba Bouafia, Dominique Hetuin, Celine Berthon, Anne Loyens, Elisabeth Bertrand, Nathalie Jouy, Thierry Idziorek, Bruno Quesnel. RIP3 is downregulated in human myeloid leukemia cells and modulates apoptosis and caspase-mediated p65/RelA cleavage. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1342. doi:10.1158/1538-7445.AM2014-1342