Necroptosis in Pulmonary Diseases: A New Therapeutic Target

Immunonutrition, Metabolism, and Programmed Cell Death in Lung Cancer: Translating Bench to Bedside

Lung cancer presents significant therapeutic challenges, motivating the exploration of novel treatment strategies. Programmed cell death (PCD) mechanisms, encompassing apoptosis, autophagy, and programmed necrosis, are pivotal in lung cancer pathogenesis and the treatment response. Dysregulation of these pathways contributes to tumor progression and therapy resistance. Immunonutrition, employing specific nutrients to modulate immune function, and metabolic reprogramming, a hallmark of cancer cells, offer promising avenues for intervention. Nutritional interventions, such as omega-3 fatty acids, exert modulatory effects on PCD pathways in cancer cells, while targeting metabolic pathways implicated in apoptosis regulation represents a compelling therapeutic approach. Clinical evidence supports the role of immunonutritional interventions, including omega-3 fatty acids, in augmenting PCD and enhancing treatment outcomes in patients with lung cancer. Furthermore, synthetic analogs of natural compounds, such as resveratrol, demonstrate promising anticancer properties by modulating apoptotic signaling pathways. This review underscores the convergence of immunonutrition, metabolism, and PCD pathways in lung cancer biology, emphasizing the potential for therapeutic exploration in this complex disease. Further elucidation of the specific molecular mechanisms governing these interactions is imperative for translating these findings into clinical practice and improving lung cancer management.

Necroptosis blockade prevents lung injury in severe influenza

Severe influenza A virus (IAV) infections can result in hyper-inflammation, lung injury and acute respiratory distress syndrome1-5 (ARDS), for which there are no effective pharmacological therapies. Necroptosis is an attractive entry point for therapeutic intervention in ARDS and related inflammatory conditions because it drives pathogenic lung inflammation and lethality during severe IAV infection6-8 and can potentially be targeted by receptor interacting protein kinase 3 (RIPK3) inhibitors. Here we show that a newly developed RIPK3 inhibitor, UH15-38, potently and selectively blocked IAV-triggered necroptosis in alveolar epithelial cells in vivo. UH15-38 ameliorated lung inflammation and prevented mortality following infection with laboratory-adapted and pandemic strains of IAV, without compromising antiviral adaptive immune responses or impeding viral clearance. UH15-38 displayed robust therapeutic efficacy even when administered late in the course of infection, suggesting that RIPK3 blockade may provide clinical benefit in patients with IAV-driven ARDS and other hyper-inflammatory pathologies.

RIPK1 in the inflammatory response and sepsis: Recent advances, drug discovery and beyond

Cytokine storms are an important mechanism of sepsis. TNF-α is an important cytokine. As a regulator of TNF superfamily receptors, RIPK1 not only serves as the basis of the scaffold structure in complex I to promote the activation of the NF-κB and MAPK pathways but also represents an important protein in complex II to promote programmed cell death. Ubiquitination of RIPK1 is an important regulatory function that determines the activation of cellular inflammatory pathways or the activation of death pathways. In this paper, we introduce the regulation of RIPK1, RIPK1 PANoptosome's role in Inflammatory and sepsis, and perspectives.

Identification and Analysis of Necroptosis-Related Genes in COPD by Bioinformatics and Experimental Verification

Chronic obstructive pulmonary disease (COPD) is a heterogeneous and complex progressive inflammatory disease. Necroptosis is a newly identified type of programmed cell death. However, the role of necroptosis in COPD is unclear. This study aimed to identify necroptosis-related genes in COPD and explore the roles of necroptosis and immune infiltration through bioinformatics. The analysis identified 49 differentially expressed necroptosis-related genes that were primarily engaged in inflammatory immune response pathways. The infiltration of CD8+ T cells and M2 macrophages in COPD lung tissue was relatively reduced, whereas that of M0 macrophages was increased. We identified 10 necroptosis-related hub genes significantly associated with infiltrated immune cells. Furthermore, 7 hub genes, CASP8, IL1B, RIPK1, MLKL, XIAP, TNFRSF1A, and CFLAR, were validated using an external dataset and experimental mice. CFLAR was considered to have the best COPD-diagnosing capability. TF and miRNA interactions with common hub genes were identified. Several related potentially therapeutic molecules for COPD were also identified. The present findings suggest that necroptosis occurs in COPD pathogenesis and is correlated with immune cell infiltration, which indicates that necroptosis may participate in the development of COPD by interacting with the immune response.

Carotid Body-Mediated Chemoreflex Function in Aging and the Role of Receptor-Interacting Protein Kinase

Ventilatory impairment during aging has been linked to carotid body (CB) dysfunction. Anatomical/morphological studies evidenced CB degeneration and reductions in the number of CB chemoreceptor cells during aging. The mechanism(s) related to CB degeneration in aging remains elusive. Programmed cell death encompasses both apoptosis and necroptosis. Interestingly, necroptosis can be driven by molecular pathways related to low-grade inflammation, one hallmark of the aging process. Accordingly, we hypothesized that necrotic cell death dependent on receptor-interacting protein kinase-3 (RIPK3) may contribute, at least in part, to impair CB function during aging. Adult (3 months) and aged (24 months) wild type (WT) and RIPK3^-/- mice were used to study chemoreflex function. Aging results in significant reductions in both the hypoxic (HVR) and hypercapnic ventilatory responses (HCVR). Adult RIPK3^-/- mice showed normal HVR and HCVR compared to adult WT mice. Remarkable, aged RIPK3^-/- mice displayed no reductions in HVR nor in HCVR. Indeed, chemoreflex responses obtained in aged RIPK3^-/- KO mice were undistinguishable from the ones obtained in adult WT mice. Lastly, we found high prevalence of breathing disorders during aging and this was absent in aged RIPK3^-/- mice. Together our results support a role for RIPK3-mediated necroptosis in CB dysfunction during aging.

[Hydroxysafflor yellow A attenuates heat stroke-induced acute lung injury in mice by inhibiting necroptosis]

OBJECTIVE

To investigate the protective effect of hydroxysafflor yellow A (HSYA) against heat stroke (HS)-induced acute lung injury and its possible mechanism.

METHODS

The optimal dose of HSYA pretreatment via intraperitoneal injection prior to HS was determined in a mice by observing heat tolerance of the mice. C57BL/6J mice were pretreated with HSYA at the optimal dose or with Nec-1 (a RIP1 activation inhibitor) before HS, and the changes in core body temperature and survival of the mice were observed during the 72-h recovery period. At different stages of recovery, lung tissues, bronchoalveolar lavage fluid and blood samples were collected from the mice for assessing lung tissue pathology, wet-to-dry weight ratio and water content of the lungs; leukocyte and neutrophil counts, total protein levels and HMGB1 level in the bronchoalveolar lavage fluid (BLF) were also detected. Serum levels of TNF-α, IL-6 and HMGB1 were detected with ELISA, and the expression levels of RIP1, RIP3, MLKL-s358, MLKL and MLKL-s358 proteins in the lung tissues were detected using Western blotting.

RESULTS

HSYA pretreatment at the moderate and high doses significantly improved heat tolerance of the mice with comparable effects. At the optimal dose of 2.25 mg/kg, HSYA pretreatment significantly increased heat tolerance of the mice (P<0.05), showing a similar effect with Nec-1 pretreatment. Pretreatment with HSYA and Nec-1 both significantly increased survival rate of the mice (P<0.05), lowered histopathological score and water content of the lungs, and reduced the levels of TNF-α, IL-6 and HMGB1 (P<0.05), leukocyte and neutrophil counts, and total protein and HMGB1 levels in the BLF (P<0.05). The mice during recovery from HS showed significantly increased RIP1 expression and MLKL-s358 phosphorylation level in the lung tissue (P<0.05), which were obviously lowered by HSYA pretreatment of the mice.

CONCLUSION

Severe HS results in necroptosis in the lung tissue of mice, which can be alleviated by HSYA pretreatment.

Roles of RIPK3 in necroptosis, cell signaling, and disease

Receptor-interacting protein kinase-3 (RIPK3, or RIP3) is an essential protein in the "programmed" and "regulated" cell death pathway called necroptosis. Necroptosis is activated by the death receptor ligands and pattern recognition receptors of the innate immune system, and the findings of many reports have suggested that necroptosis is highly significant in health and human disease. This significance is largely because necroptosis is distinguished from other modes of cell death, especially apoptosis, in that it is highly proinflammatory given that cell membrane integrity is lost, triggering the activation of the immune system and inflammation. Here, we discuss the roles of RIPK3 in cell signaling, along with its role in necroptosis and various pathways that trigger RIPK3 activation and cell death. Lastly, we consider pathological situations in which RIPK3/necroptosis may play a role.

Pathogenesis of pneumonia and acute lung injury

Pneumonia and its sequelae, acute lung injury, present unique challenges for pulmonary and critical care healthcare professionals, and these challenges have recently garnered global attention due to the ongoing Sars-CoV-2 pandemic. One limitation to translational investigation of acute lung injury, including its most severe manifestation (acute respiratory distress syndrome, ARDS) has been heterogeneity resulting from the clinical and physiologic diagnosis that represents a wide variety of etiologies. Recent efforts have improved our understanding and approach to heterogeneity by defining sub-phenotypes of ARDS although significant gaps in knowledge remain. Improving our mechanistic understanding of acute lung injury and its most common cause, infectious pneumonia, can advance our approach to precision targeted clinical interventions. Here, we review the pathogenesis of pneumonia and acute lung injury, including how respiratory infections and lung injury disrupt lung homoeostasis, and provide an overview of respiratory microbial pathogenesis, the lung microbiome, and interventions that have been demonstrated to improve outcomes-or not-in human clinical trials.

Ca2+/Calmodulin-Dependent Protein Kinase II Regulation by RIPK3 Alleviates Necroptosis in Transverse Arch Constriction-Induced Heart Failure

Some studies have reported that the activation of Ca²⁺/calmodulin dependent protein kinase (CaMKII) plays a vital role in the pathogenesis of cardiovascular disease. Moreover, receptor interacting protein kinase 3 (RIPK3)-mediated necroptosis is also involved in the pathological process of various heart diseases. In the present study, we aimed to investigate the effect of RIPK3-regulated CaMKII on necroptosis in heart failure (HF) and its underlying mechanism. Wild type (WT) and RIPK3-depleted (RIPK3^–/–) mice were treated with transverse arch constriction (TAC). After 6 weeks, echocardiography, myocardial injury, CaMKII activity, necroptosis, RIPK3 expression, mixed lineage kinase domain-like protein (MLKL) phosphorylation, and mitochondrial ultrastructure were measured. The results showed that TAC aggravated cardiac dysfunction, CaMKII activation, and necroptosis in WT mice. However, depletion of RIPK3 alleviated cardiac insufficiency, CaMKII activation, and necroptosis in TAC-treated mice. To verify the experimental results, WT mice were transfected with AAV-vector and AAV-RIPK3 shRNA, followed by TAC operation. The findings were consistent with the expected results. Collectively, our current data indicated that the activation of CaMKII, MLKL and necroptosis in HF mice were increased in a RIPK3-dependent manner, providing valuable insights into the pathogenesis and treatment strategy of HF.