Neuronal cell death in the central nervous system has always been a challenging process to decipher. In physiological condition, neuronal cell death is restricted in the adult brain even as people ages. However, in pathological conditions of various neurodegenerative diseases, the cell death and shrinkage of a specific brain region represent a fundamental pathological feature across different neurodegenerative diseases. In this review, we will briefly go through the general pathways of cell death and describe the evidence of the cell deaths in the context of common neurodegenerative diseases individually, discussing our current understandings of cell death in connecting with the renowned pathogenic proteins, including tau, amyloid-beta, alpha-synuclein, huntingtin, and TDP-43.

Ceramide is a lipid that regulates cell death including apoptosis and necroptosis and acts as a powerful tumor suppressor. These characteristics have supported the development of ceramide-based cancer therapeutics. In the present study, ceramide mimetics (RT-25, RT-71 and YM-07) were designed and chemically synthesized, and their potential as necroptosis-inducing chemotherapeutic reagents was examined. RT-71 and YM-07, but not RT-25, potently decreased cell viability in multiple cancer cell lines. The ranges of IC50 values for RT-71 and YM-07 were 8.4–40.8 µM and 4.4–23.7 µM, respectively. Cleavage of PARP, an apoptosis marker, was not observed in MCF-7 cells treated with the mimetics. To determine the effects on necroptotic cell death, we used siRNAs specific to mixed lineage kinase domain-like protein (MLKL). MLKL knockdown significantly suppressed the cell death induced by YM-07 but not RT-71. These results suggest that YM-07 exhibits pro-necroptotic activity. Taken together, these findings indicate ceramide mimetic YM-07 as a lead compound for developing MLKL-activating necroptotic reagents. Our results help establish a foundation for pro-necroptotic therapy for cancer.

Necroptosis is an inflammatory form of lytic programmed cell death that is thought to have evolved to defend against pathogens. Genetic deletion of the terminal effector protein – MLKL – shows no overt phenotype in the C57BL/6 mouse strain under conventional laboratory housing conditions. Small molecules that inhibit necroptosis by targeting the kinase activity of RIPK1, one of the main upstream conduits to MLKL activation, have shown promise in several murine models of non-infectious disease and in phase II human clinical trials. This has triggered multi-billion-dollar investments into the emerging class of necroptosis blocking drugs, and the potential utility of targeting the terminal effector is being closely scrutinised. Here we review murine models of disease, both genetic deletion and mutation, that investigate the role of MLKL. We summarize a series of examples from several broad disease categories including ischemia reperfusion injury, sterile inflammation, pathogen infection and haematological stress. Elucidating MLKL’s contribution to mouse models of disease is an important first step to identify human indications that stand to benefit most from MLKL-targeted drug therapies.

Prostate cancer (PCa) is a complex disease and the cause of one of the highest cancer-related mortalities in men worldwide. Annually, more than 1.2 million new cases are diagnosed globally, accounting for 7% of newly diagnosed cancers in men. Programmed cell death (PCD) plays an essential role in removing infected, functionally dispensable or potentially neoplastic cells. Apoptosis is the canonical form of PCD with no inflammatory responses elicited, and the close relationship between apoptosis and PCa has been well studied. Necroptosis and pyroptosis are two lytic forms of PCD resulting in the release of intracellular contents, which induces inflammatory responses. An increasing number of studies have confirmed that necroptosis and pyroptosis are also closely related to the occurrence and progression of PCa. Recently, a novel form of PCD named PANoptosis, which is a combination of apoptosis, necroptosis, and pyroptosis, revealed the attached connection among them and may be a promising target for PCa. Apoptosis, necroptosis, pyroptosis and PANoptosis are good examples to better understand the mechanism underlying PCD in PCa. This review aims to summarize the emerging roles and therapeutic potential of apoptosis, necroptosis, pyroptosis and PANoptosis in PCa.

Pancreatic cancer (PC) is the seventh leading cause of cancer-related death. PC incidence has con-tinued to increase by about 1% each year in both men and women. Although the 5‐year relative survival rate of PC has increased from 3% to 12%, it is still the lowest among cancers. Hence, novel therapeutic strategies are urgently needed. Challenges in PC-targeted therapeutic strate-gies stem from the high PC heterogeneity and from the poorly understood interplay between cancer cells and the surrounding microenvironment. Signaling pathways that drive PC cell growth have been the subject of intense scrutiny and interest has been attracted by necroptosis, a distinct type of programmed cell death. In this review, we provide a historical background on necroptosis and a detailed analysis of the ongoing debate on the role of necroptosis in PC malignant progression.

To maintain proteostasis, cells must integrate information and activities that supervise protein synthesis, protein folding, conformational stability, and also protein degradation. Extrinsic and intrinsic conditions can both impact on normal proteostasis, causing the appearance of proteotoxic stress. Initially, proteotoxic stress elicits adaptive responses aimed to restore proteostasis, allowing cells to survival the stress condition. However, if the proteostasis restoration fails, a permanent and sustained proteotoxic stress can be deleterious and cell death ensues. Many cancer cells convive with high levels of proteotoxic stress and this condition could be exploited in a therapeutic perspective. Understanding the cell death pathways engaged by proteotoxic stress is instrumental to better hijack the proliferative fate of cancer cells.

Cisplatin is a widely used anticancer drug for treating solid tumors, but it is associated with severe side effects, including nephrotoxicity. Various studies have suggested that the nephrotoxicity of cisplatin could be overcome; nonetheless, an effective adjuvant drug has not yet been established. Oleanolic acid acetate (OAA), a triterpenoid isolated from Vigna angularis, is commonly used to treat inflammatory and allergic diseases. This study aimed to investigate the protective effects of OAA against cisplatin-induced apoptosis and necroptosis using TCMK-1 cells and a mouse model. In cisplatin-treated TCMK-1 cells, OAA treatment significantly reduced Bax and cleaved-caspase3 expression, whereas increased Bcl-2 expression. Moreover, in cisplatin-induced kidney injury mouse model, OAA treatment alleviated weight loss in the body and major organs and also relieved cisplatin-induced nephrotoxicity symptoms. RNA sequencing analysis of kidney tissues identified lipocalin-2 as the most upregulated gene by cisplatin. Additionally, necroptosis-related genes such as receptor interacting protein kinase (RIPK) and mixed lineage kinase domain like (MLKL) were identified. In vitro study, the phosphorylation of RIPKs and MLKL was reduced by OAA pretreatment in both cisplatin-treated cells and cells boosted by co-treatment with z-VAD-FMK. In conclusion, OAA could protect the kidney from cisplatin-induced nephrotoxicity and may serve as an anticancer adjuvant.

SARS-CoV-2 was detected in China in December 2019. Myocardial injury is a crucial presentation of COVID-19, based on the association of ACE-2 and SARS-CoV-2. Down-regulating ACE-2 decreases the cardioprotective effects of angiotensin, leading to a higher TNF-α activation. TNF-α causes the inflammatory response in the myocardial damage as an apoptotic inducer. Moreover, as an inducer of necroptosis, TNF-α binds to a part of TNF receptor 1, which involves receptor-interacting protein 1 (RIP1) and causes cell death through RIP1 inhibition and NF-κB stimulation, which are also done through Tpl-2. Calcineurin controls the Tpl-2-driven NFAT stimulation. Bcl-2 or Bcl-X_L entirely blocks these pathways. Bcl-2 overexpression reduces FasL expression with a mechanism based on Bcl-2 inhibiting the NFAT. Moreover, the Fas/FasL system activates apoptosis in various cells. Bcl-XL stimulates Fas-related cell death. Additionally, TNF-α, as a part of inflammatory cytokine storms, indirectly interacts with NFAT/Bcl-2 through Tpl-2/NF-κB. Diversely, TNF-α and IL-1ẞ, the basis of inflammatory cytokine storms in COVID-19, can stimulate generating NO. Also, IL-2 is highly up-regulated in COVID-19 patients and stimulates NO generation in patients. TNF-α can provoke the generation of superoxides in neutrophils. A well-determined mechanism is the intracellular production of NO via calcium-calmodulin-dependent NO synthase (NOS). NO enhances NFAT’s calcium-dependent activity. Also, Intra/extracellular calcium exchange activates calcineurin and its related molecule, NFAT. Nitration provokes RIP1 necroptosis cascade, with respiratory complex I. Nitrites converse protection against ischemia-reperfusion injuries in the myocardium. Regulating this intrinsic molecular pathway can prevent the necroptosis of cardiomyocytes.

Cisplatin induces early-onset ototoxicity, resulting in hearing loss. The exact mechanism by which cisplatin causes ototoxicity remains unclear. The purpose of this study was to identify the involvement of receptor-interacting protein kinase(RIP)3-dependent necroptosis in cisplatin-induced ototoxicity in animal models. Sprague–Dawley rats (SD, 8 week) were treated via intraperitoneal (i.p) injection with cisplatin (16 mg/kg for 1 day), and their hearing thresholds were was measured by the auditory brainstem response (ABR) method. Hematoxylin and eosin (H-E) staining, immunohistochemistry, and western blots were performed to determine the effect of cisplatin-induced ototoxicity on cochlear morphology. H-E stains outlined necroptotic changes in the organ of Cortis (OCs) and spiral ganglion neurons (SGNs). Additionally, immunohistochemistry and western blot analysis showed overexpression of RIP3 in the OCs and SGNs that were treated with cisplatin. These results suggest that RIP3-dependent necroptosis was substantial in cisplatin-induced ototoxicity; inner cochlear regions, the OCs, and SGNs were especially sensitive to necroptosis.

Apoptosis, necroptosis, and autophagy are cellular mechanisms by which cells are programmed to die under a wide range of physiological and developmental stimuli. A multitude of protein mediators of programmed cell death have been identified and apoptosis, necroptosis, and autophagy signals have been found to utilize common pathways elucidating the proteins involved. This narrative review focuses on caspase-dependent and caspase-independent programmed cell death systems. Included studies of caspase-dependent programmed cell death include extrinsic pathway apoptotic mechanisms including phosphatidylserine (PS), FAS (APO-1/CD95), Tumor Necrosis Factor (TNF) Receptor type 1 (TNF-R1) and TNF-Related Apoptosis-Inducing Ligand (TRAIL) and intrinsic or mitochondrial pathway such as Cytochrome C, the Bcl-2 family of proteins and Smac/Diablo. The Bcl-2 family has apoptotic mediators Bcl-2-associated X protein (Bax) and Bcl-2 homologous antagonist/killer (Bak), Bcl-2-Interacting Protein BIM (Bim), Bcl-2 agonist of cell death (Bad), Bid, Bcl-2 adenovirus E1B 19kDa-interacting protein 1 NIP3 (Bnip3), BMF, HRK, Noxa and PUMA and anti-apoptotic proteins such as Bcl-2 itself, Mcl-1, Bcl-w, A1, and Bcl-XL. Moreover, caspase-independent programmed cell death pathways include the mitochondrial pathway with the protein mediators Apoptosis Inducing Factor (AIF), and Endonuclease G, the pathways Necroptosis, and Autophagy. Understanding programmed cell death from those reported in this review could shed substantial light on the processes of biological homeostasis. In addition, identifying specific proteins involved in these processes is mandatory to identify molecular biomarkers as well as therapeutic targets. This knowledge could provide the ability to modulate the programmed cell death response and could lead to new therapeutic interventions in a wide range of diseases.