Brain neurons play a crucial role to maintain organism health in response to macro/micro-environmental biophysical and biochemical cues, and their dysfunction and death drive aging and diseases. However, cellular mechanisms controlling neuronal health are incompletely understood. Drosophila has proven a paramount model to understand fundamental pathways of tissue development, homeostasis, and cell death in health and disease. Among these pathways, the regulation of nuclear structure and function, including genome organization, RNA synthesis and processing, DNA damage repair, and nucleocytoplasmic transport, has been shown to play a major role. In this regulation, the nucleoskeleton, a meshwork of type A/C and B Lamin proteins, provides an interface between the cytoskeleton and chromatin, controlling (epi)genome dynamics and nucleocytoplasmic compartmentalization, also by interacting with the inner nuclear membrane and pore complexes. In postmitotic neurons, LaminB is the major nucleoskeletal component. In this Review, I focus on the key role of nuclear LaminB dynamics in neuronal homeostasis in aging and cell death, highlighting the power of Drosophila models to uncover the underlying fundamental mechanisms. In this context, I spotlight that the regulation of nuclear LaminB structure and function is emerging as a stress-integration gatekeeper controlling neuronal response to macro/micro-environmental biophysical and biochemical cues, which maintains neuronal health, and whose impairment drives neuronal aging and non-apoptotic cell death in neurodegenerative diseases.
Synapses are ‘double-edged swords’, being appropriate for the quick transmission of impulses in one hand, but vulnerable to the oxidative stress in another hand. When the presynaptic terminals convey neurotransmission by altering structure of lipid molecules in response to physiological stimuli, membrane remodeling occurs rapidly at dendrites to make synaptic vesicles and release neurotransmitters. However, excessive stimuli due to stresses such as ischemia, trauma, irradiation, etc., cause changes of lipidomes at the presynaptic membranes to generate various lysophospholipids by overactivating phospholipase A 2 (PLA 2) and autotaxin. Lysophosphatidylcholine (LysoPC) is generated from the membraneous phosphatidylcholine (PC) via PLA 2, while lysophosphatidic acid (LysoPA) is generated from LysoPC via autotaxin. LysoPC at the synaptic area enhances the membrane excitability, and LysoPA interferes with the cytoskeleton, both facilitating neuronal injuries. Here, the author focused on the ultrastructural visualization of lysophospholipids to elucidate detrimental effects of stress-induced lysophospholipids which were generated at the synaptic area. Lipidomics can detect LysoPC and LysoPA involved in the body fluids, however, cannot detect LysoPC accumulated in the restricted brain area. This is due to an insufficient spatial resolution of standard lipidomic/mass spectrometry approaches, and/or a technical limitation specific to LysoPC extraction/detection in the brain tissue. Since tannic acid interacts with the choline head-group of PC or LysoPC, and tannic acid-choline aggregates are postfixed by osmium tetroxide, it was utilized to visualize them by electron microscopy. Using tannic acid, PC is ultrastructurally observed as distinct double membrane structures, whereas LysoPC is visualized as extramembraneous, multilamellar bodies. In the monkey brain after ischemia, multilamellar bodies were clearly seen in the vicinity of synaptic vesicle membranes of hippocampal neurons. This review highlights the regional toxicity of lysophopholipids due to the transition from physiological lipid remodeling to pathological PLA 2 overactivation.
Laura Lossi, Marco Sbriz, Claudia Castagna, Adalberto Merighi
Regulated cell death (RCD) encompasses genetically encoded and pharmacologically modifiable pathways that govern cellular demise. In the nervous system, RCD assumes unique biological and clinical relevance due to neurons’ post-mitotic status, the functional integration of neural circuits, and the central role of glial cells in homeostasis and inflammation. This review synthesizes current knowledge on apoptotic and non-apoptotic RCD modalities in neurons and glia, integrates molecular mechanisms with ultrastructural hallmarks, and discusses specific patterns of pathway engagement. We emphasize compartmentalized death, pathway crosstalk, and cell-type specificity.
Immune checkpoint inhibitors (ICIs) have transformed cancer care, yet durable responses remain limited in a majority of patients. This is particularly true of immunologically cold tumors, which are characterized by insufficient T-cell infiltration, low antigenicity, impaired adjuvanticity, and an immunosuppressive tumor microenvironment (TME). Z-form Nucleic Acid (Z-NA) Binding protein 1 (ZBP1)-initiated signaling, by overcoming these barriers, offers a mechanistic solution to rekindling ICI responsiveness in cold tumors. ZBP1 is an immune sensor which detects viral or endogenous Z-NAs, binds the kinase RIPK3, and activates Mixed Lineage Kinase Like pseudokinase (MLKL)-mediated necroptosis. ZBP1-initiated signaling can also inflame tumors non-cytolytically, including by activating inflammatory gene expression. Tumors frequently inactivate ZBP1 signaling, most notably by epigenetically silencing RIPK3. However, TME cells, particularly inflammatory cancer-associated fibroblasts (iCAFs), retain RIPK3 competence and represent a readily exploitable therapeutic vulnerability for activation of ZBP1-mediated immunogenic signaling within the tumor mass. Here, we discuss emerging strategies to activate ZBP1 within cold tumors as a means to enhance ICI-driven anti-tumor responses.
Biliary Tract Cancers (BTCs), including cholangiocarcinoma and gallbladder cancer, are aggressive malignancies characterized by late diagnosis, high mortality, and intrinsic resistance to standard chemotherapeutic regimens like gemcitabine and cisplatin. A critical barrier to improving therapeutic outcomes is the historical reliance on 2D monolayer cultures. These conventional models fail to recapitulate the complex Tumor Microenvironment (TME), leading to poor predictive validity and high attrition rates in drug discovery. This review critically examines the paradigm shift from reductionist 2D cultures to advanced 3D tumor models—as superior in vitro platforms for decoding drug resistance and apoptosis evasion in BTCs, while acknowledging that 2D model limitations represent only one component of a broader translational pipeline that includes animal models, biomarker gaps, and anatomical challenges. The article highlights that 3D architectures uniquely recapitulate physiological barriers absent in monolayers, including hypoxia-driven metabolic reprogramming, dense Extracellular Matrix (ECM) shielding, and drug distribution gradients. These models reveal specific “multicellular resistance” (MCR) mechanisms, such as the dysregulation of the Bcl-2 rheostat (particularly Bcl-xL and Mcl-1 dependence). Furthermore, 3D systems provide a more accurate context for investigating alternative cell death pathways, including ferroptosis and necroptosis, and for identifying quiescent cancer stem cell populations protected by the niche. 3D tumor models, particularly PDOs, serve as high-fidelity “clinical avatars” that bridge the translational gap between preclinical screening and precision oncology. While challenges regarding standardization, immune component integration, and scalability remain, the adoption of these physiologically relevant systems is imperative for developing effective combinatorial therapies and overcoming the profound chemoresistance inherent to BTCs.
