Disulfidptosis, A Novel Cell Death Pathway: Molecular Landscape and Therapeutic Implications.

Programmed cell death is pivotal for several physiological processes, including immune defense. Further, it has been implicated in the pathogenesis of developmental disorders and the onset of numerous diseases. Multiple modes of programmed cell death, including apoptosis, pyroptosis, necroptosis, and ferroptosis, have been identified, each with their own unique characteristics and biological implications. In February 2023, Liu Xiaoguang and his team discovered "disulfidptosis," a novel pathway of programmed cell death. Their findings demonstrated that disulfidptosis is triggered in glucose-starved cells exhibiting high expression of a protein called SLC7A11. Furthermore, disulfidptosis is marked by a drastic imbalance in the NADPH/NADP+ ratio and the abnormal accumulation of disulfides like cystine. These changes ultimately lead to the destabilization of the F-actin network, causing cell death. Given that high SLC7A11 expression is a key feature of certain cancers, these findings indicate that disulfidptosis could serve as the basis of innovative anti-cancer therapies. Hence, this review delves into the discovery of disulfidptosis, its underlying molecular mechanisms and metabolic regulation, and its prospective applications in disease treatment.

The role of snapin in regulation of brain homeostasis.

Brain homeostasis refers to the normal working state of the brain in a certain period, which is important for overall health and normal life activities. Currently, there is a lack of effective treatment methods for the adverse consequences caused by brain homeostasis imbalance. Snapin is a protein that assists in the formation of neuronal synapses and plays a crucial role in the normal growth and development of synapses. Recently, many researchers have reported the association between snapin and neurologic and psychiatric disorders, demonstrating that snapin can improve brain homeostasis. Clinical manifestations of brain disease often involve imbalances in brain homeostasis and may lead to neurological and behavioral sequelae. This article aims to explore the role of snapin in restoring brain homeostasis after injury or diseases, highlighting its significance in maintaining brain homeostasis and treating brain diseases. Additionally, it comprehensively discusses the implications of snapin in other extracerebral diseases such as diabetes and viral infections, with the objective of determining the clinical potential of snapin in maintaining brain homeostasis.

Ruxolitinib, a promising therapeutic candidate for traumatic brain injury through maintaining the homeostasis of cathepsin B.

Traumatic brain injury (TBI) is one of the main causes of death and disability in the world. Owing to the heterogeneity and complexity of TBI pathogenesis, there is still no specific drug. Our previous studies have proved the neuroprotective effect of Ruxolitinib (Ruxo) on TBI, but further are needed to explore the potent mechanisms and potential translational application. Compelling evidence indicates that Cathepsin B (CTSB) plays an important role in TBI. However, the relationships between Ruxo and CTSB upon TBI remain non-elucidated. In this study, we established a mouse model of moderate TBI to clarify it. The neurological deficit in the behavioral test was alleviated when Ruxo administrated at 6 h post-TBI. Additionally, Ruxo significantly reduced the lesion volume. As for the pathological process of acute phase, Ruxo remarkably reduced the expression of proteins associated with cell demise, neuroinflammation, and neurodegeneration. Then the expression and location of CTSB were detected respectively. We found that the expression of CTSB exhibits a transient decrease and then persistent increase following TBI. The distribution of CTSB, mainly located at NeuN-positive neurons was unchanged. Importantly, the dysregulation of CTSB expression was reversed with the treatment of Ruxo. The timepoint was chosen when CTSB decreased, to further analyze its change in the extracted organelles; and Ruxo maintained the homeostasis of it in sub-cellular. In summary, our results demonstrate that Ruxo plays neuroprotection through maintaining the homeostasis of CTSB, and will be a promising therapeutic candidate for TBI in clinic.

Upregulation of RAB7 is related to neuronal pyroptosis after spinal cord injury in rats.

Rab7 belongs to the Ras small GTPase superfamily, and abnormal expression of Rab7 can cause neuropathy and lipid metabolism diseases. Studies have shown that Rab7 plays a crucial role in the inner membrane translocase. However, the role of Rab7 in the regulatory mechanisms of cell survival in spinal cord injury remains unknown. We used a rat spinal cord injury (SCI) model to explore the cellular localization and expression of Rab7 after SCI in this study. Western blot analysis showed that Rab7 was expressed in the spinal cord tissue. On the first day, it significantly increased and peaked after SCI on the third day. Furthermore, western blotting also demonstrated that pyroptosis-related protein Gasdermin D (GSDMD), Caspase-1, apoptosis-associated speck-like protein (ASC) expression peaked after the third-day post-injury. Importantly, the immunohistochemistry analysis revealed that Rab7 was completely colocalized with ASC in neurons after SCI. These results suggested that Rab7 was colocalized with NeuN and ASC, involved in the pyroptosis of neurons, and closely related to the spinal cord after injury.

Brain-specific loss of Abcg1 disturbs cholesterol metabolism and aggravates pyroptosis and neurological deficits after traumatic brain injury.

Based on accumulating evidence, cholesterol metabolism dysfunction has been suggested to contribute to the pathophysiological process of traumatic brain injury (TBI) and lead to neurological deficits. As a key transporter of cholesterol that efflux from cells, the ATP-binding cassette (ABC) transporter family exerts many beneficial effects on central nervous system (CNS) diseases. However, there is no study regarding the effects and mechanisms of ABCG1 on TBI. As expected, TBI resulted in the different time-course changes of cholesterol metabolism-related molecules in the injured cortex. Considering ABCG1 is expressed in neuron and glia post-TBI, we generated nestin-specific Abcg1 knockout (Abcg1-KO) mice using the Cre/loxP recombination system. These Abcg1-KO mice showed reduced plasma high-density lipoprotein cholesterol levels and increased plasma lower-density lipoprotein cholesterol levels under the base condition. After TBI, these Abcg1-KO mice were susceptible to cholesterol metabolism turbulence. Moreover, Abcg1-KO exacerbated TBI-induced pyroptosis, apoptosis, neuronal cell insult, brain edema, neurological deficits, and brain lesion volume. Importantly, we found that treating with retinoid X receptor (RXR, the upstream molecule of ABCG1) agonist, bexarotene, in Abcg1-KO mice partly rescued TBI-induced neuronal damages mentioned above and improved functional deficits versus vehicle-treated group. These data show that, in addition to regulating brain cholesterol metabolism, Abcg1 improves neurological deficits through inhibiting pyroptosis, apoptosis, neuronal cell insult, and brain edema. Moreover, our findings demonstrate that the cerebroprotection of Abcg1 on TBI partly relies on the activation of the RXRalpha/PPARgamma pathway, which provides a potential therapeutic target for treating TBI.

The Role of Copper Homeostasis in Brain Disease.

In the human body, copper is an important trace element and is a cofactor for several important enzymes involved in energy production, iron metabolism, neuropeptide activation, connective tissue synthesis, and neurotransmitter synthesis. Copper is also necessary for cellular processes, such as the regulation of intracellular signal transduction, catecholamine balance, myelination of neurons, and efficient synaptic transmission in the central nervous system. Copper is naturally present in some foods and is available as a dietary supplement. Only small amounts of copper are typically stored in the body and a large amount of copper is excreted through bile and urine. Given the critical role of copper in a breadth of cellular processes, local concentrations of copper and the cellular distribution of copper transporter proteins in the brain are important to maintain the steady state of the internal environment. The dysfunction of copper metabolism or regulatory pathways results in an imbalance in copper homeostasis in the brain, which can lead to a myriad of acute and chronic pathological effects on neurological function. It suggests a unique mechanism linking copper homeostasis and neuronal activation within the central nervous system. This article explores the relationship between impaired copper homeostasis and neuropathophysiological progress in brain diseases.

Surface-fill H2S-releasing silk fibroin hydrogel for brain repair through the repression of neuronal pyroptosis.

Traumatic brain injury (TBI) remains the major cause of disability and mortality worldwide due to the persistent neuroinflammation and neuronal death induced by TBI. Among them, pyroptosis, a specific type of programmed cell death (PCD) triggered by inflammatory signals, plays a significant part in the pathological process after TBI. Inhibition of neuroinflammation and pyroptosis is considered a possible strategy for the treatment of TBI. In our previous study, exogenous hydrogen sulfide(H2S) exerted a neuroprotective effect after TBI. Here, we developed a surface-fill H2S-releasing silk fibroin (SF) hydrogel (H2S@SF hydrogel) to achieve small-dose local administration and avoid volatile and toxic side effects. We used a controlled cortical impact (CCI) to establish a mild TBI model in mice to examine the effect of H2S@SF hydrogel on TBI-induced pyroptosis. We found that H2S@SF hydrogel inhibited the expression of H2S synthase in neurons after TBI and significantly inhibited TBI-induced neuronal pyroptosis. In addition, immunofluorescence staining results showed that the necroptosis protein receptor-interacting serine/threonine-protein kinase 1 (RIPK1) partially colocalized with the pyroptosis protein Gasdermin D (GSDMD) in the same cells. H2S@SF hydrogel can also inhibit the expression of the necroptosis protein. Moreover, H2S@SF hydrogel also alleviates brain edema and the degree of neurodegeneration in the acute phase of TBI. The neuroprotective effect of H2S@SF hydrogel was further confirmed by wire-grip test, open field test, Morris water maze, beam balance test, radial arm maze, tail suspension, and forced swimming test. Lastly, we also measured spared tissue volume, reactive astrocytes and activated microglia to demonstrate H2S@SF hydrogel impacts on long-term prognosis in TBI. Our study provides a new theoretical basis for the treatment of H2S after TBI and the clinical application of H2S@SF hydrogel. STATEMENT OF SIGNIFICANCE: Silk fibroin (SF) hydrogel controls the release of hydrogen sulfide (H2S) to inhibit neuronal pyroptosis and neuroinflammation in injured brain tissue. In this study, we synthesized a surface-fill H2S-releasing silk fibroin hydrogel, which could slowly release H2S to reshape the homeostasis of endogenous H2S in injured neurons and inhibit neuronal pyroptosis in a mouse model of traumatic brain injury. Meanwhile, H2S@SF hydrogel could alleviate brain edema and the degree of neurodegeneration, improve motor dysfunction, anxious behavior and memory impairment caused by TBI, reduce tissue loss and ameliorate neuroinflammation. Our study provides a new theoretical basis for the treatment of H2S after TBI and the clinical application of H2S@SF hydrogel.

Implantation of injectable SF hydrogel with sustained hydrogen sulfide delivery reduces neuronal pyroptosis and enhances functional recovery after severe intracerebral hemorrhage.

Hydrogen sulfide (H2S), an important endogenous signaling molecule, plays an important neuroprotective role in the central nervous system. However, there is no ideal delivery material or method involving the sustained and controlled release of H2S for clinical application in brain diseases. Silk fibroin (SF)-based hydrogels have become a potentially promising strategy for local, controlled, sustained drug release in the treatment of various disorders. Here, we show a silk fibroin (SF)-based hydrogel with sustained H2S delivery (H2S@SF hydrogel) is effective in treating brain injury through stereotactic orthotopic injection in a severe intracerebral hemorrhage (ICH) mouse model. In this study, we observed H2S@SF hydrogel sustained H2S release in vitro and in vivo. The physicochemical properties of H2S@SF hydrogel were studied using FE-SEM, Raman spectroscopy and Rheological analysis. Treatment with H2S@SF hydrogel attenuated brain edema, reduced hemorrhage volume and improved the recovery of neurological deficits after severe ICH following stereotactic orthotopic injection. Double immunofluorescent staining also revealed that H2S@SF hydrogel may reduce cell pyroptosis in the striatum, cortex and hippocampus. However, when using endogenous H2S production inhibitor AOAA, H2S@SF hydrogel could not suppress ICH-induced cell pyroptosis. Hence, the therapeutic effect of the H2S@SF hydrogel may be partly the result of the slow-release of H2S and/or the effect of the SF hydrogel on the production of endogenous H2S. Altogether, the results exhibit promising attributes of injectable silk fibroin hydrogel and the utility of H2S-loaded injectable SF hydrogel as an alternative biomaterial toward brain injury treatment for clinical application.

Silk Fibroin Hydrogels Could Be Therapeutic Biomaterials for Neurological Diseases.

Silk fibroin, a natural macromolecular protein without physiological activity, has been widely used in different fields, such as the regeneration of bones, cartilage, nerves, and other tissues. Due to irrevocable neuronal injury, the treatment and prognosis of neurological diseases need to be investigated. Despite attempts to propel neuroprotective therapeutic approaches, numerous attempts to translate effective therapies for brain disease have been largely unsuccessful. As a good candidate for biomedical applications, hydrogels based on silk fibroin effectively amplify their advantages. The ability of nerve tissue regeneration, inflammation regulation, the slow release of drugs, antioxidative stress, regulation of cell death, and hemostasis could lead to a new approach to treating neurological disorders. In this review, we introduced the preparation of SF hydrogels and then delineated the probable mechanism of silk fibroin in the treatment of neurological diseases. Finally, we showed the application of silk fibroin in neurological diseases.

Interleukin-13 Affects the Recovery Processes in a Mouse Model of Hemorrhagic Stroke with Bilateral Tibial Fracture.

As one form of stroke, intracerebral hemorrhage (ICH) is a fatal cerebrovascular disease, which has high morbidity and mortality and lacks effective medical treatment. Increased infiltration of inflammatory cytokines coupled with pyroptotic cell death is involved in the pathophysiological process of ICH. However, little is known about whether concomitant fracture patients have the same progression of inflammation and pyroptosis. Hence, we respectively established the mouse ICH model and ICH with bilateral tibial fracture model (MI) to explore the potential cross-talk between the above two injuries. We found that MI obviously reversed the expressions of pyroptosis-associated proteins, which were remarkably up-regulated at the acute phase after ICH. Similar results were observed in neuronal expressions via double immunostaining. Furthermore, brain edema was also significantly alleviated in mice who suffered MI, when compared with ICH alone. To better clarify the potential mechanisms that mediated this cross-talk, recombinant mouse interleukin-13 (IL-13) was used to investigate its effect on pyroptosis in the mouse MI model, in which a lower level of IL-13 was observed. Remarkably, IL-13 administration re-awakened cell death, which was mirrored by the re-upregulation of pyroptosis-associated proteins and PI-positive cell counts. The results of hemorrhage volume and behavioral tests further confirmed its critical role in regulating neurological functions. Besides, the IL-13-treated MI group showed poor outcomes of fracture healing. To sum up, our research indicates that controlling the IL-13 content in the acute phase would be a promising target in influencing the outcomes of brain injury and fracture, and meanwhile, provides new evidence in repairing compound injuries in clinics.

A case of death of purulent meningitis caused by transorbital intracranial penetrating injury due to long-term residual bamboo chopstick.

This article reports a case of death caused by purulent meningitis after a long-term transorbital intracranial penetrating injury induced by a bamboo chopstick. A 53-year-old man was pierced with a bamboo chopstick into the left orbit, and the bamboo chopstick broke off. The man remained conscious after the injury but developed paroxysmal headaches. Multiple computed tomography, computed tomography angiography, and rhinoscopy detections revealed that a puncture tract had formed from the left orbit to the right edge of the brainstem through the skull base. However, there was no apparent brain injury or cerebrovascular rupture, thus excluding the possibility of a retained intracranial foreign body by the neurosurgeon. Therefore, the man only received symptomatic and conservative treatments. Unfortunately, the man was found dead one morning, 13 months later. Autopsy and histopathological examinations revealed that he died of purulent meningitis caused by a long-term residual intracranial bamboo chopstick. A review of the relevant literature regarding the diagnosis, including diagnostic values and limitations of different imaging technologies, and treatment of residual intracranial foreign bodies, revealed that this was a case of misdiagnosis, leading to delayed treatment. This case had an indirect causal relationship between the victim's death and medical treatment. This article provides clinical strategies for diagnosing and treating such cases and a forensic perspective for identifying causes of deaths attributed to medical malpractices.

Restraint Stress Delays the Recovery of Neurological Impairments and Exacerbates Brain Damages through Activating Endoplasmic Reticulum Stress-mediated Neurodegeneration/Autophagy/Apopotosis post Moderate Traumatic Brain Injury.

Based on accumulating evidence, patients recovering from mild and moderate traumatic brain injury (TBI) often experience increased sensitivity to stressful events. However, few studies have assessed on the effects and pathophysiological mechanisms of stress on TBI. In the current study, using a mouse model of moderate TBI, we investigated whether restraint stress (RS) regulates secondary neurodegeneration and neuronal cell death, which are commonly associated with neurological dysfunctions. Our data showed that RS significantly reduced body weight recovery, delayed the recovery of neurological functions (motor function, cognitive function and anxiety-like behavior) and exacerbated the brain lesion volume after moderate TBI. Immunofluorescence results indicated that moderate TBI-induced cell insults and blood-brain barrier leakage were aggravated by RS. Further Western blotting experiments showed that RS activated endoplasmic reticulum (ER) stress excessively after moderate TBI and decreased the number of NeuN-positive cells, but increased the number of CHOP/NeuN-co-positive cells by performing immunostaining in the injured cortex after moderate TBI. Moreover, RS increased the ratios of CHOP/Aß and CHOP/p-Tau co-positive cells in the injured cortex after moderate TBI. However, blocking ER stress with the classic ER stress inhibitor salubrinal remarkably decreased apoptosis and the levels of autophagy-related proteins in the mouse model of moderate TBI plus RS. Collectively, RS delays the recovery of neurological function and deteriorates morphological damage by excessively activating ER stress-mediated neurodegeneration, apoptosis and autophagy after moderate TBI. Thus, monitoring stress levels in patients recovering from non-severe TBI may merit consideration in the future.

Autophagy inhibition facilitates wound closure partially dependent on the YAP/IL-33 signaling in a mouse model of skin wound healing.

Autophagy is a self-phagocytic and highly evolutionarily conserved intracellular lysosomal catabolic system, which plays a vital role in a variety of trauma models, including skin wound healing (SWH). However, the roles and potential mechanisms of autophagy in SWH are still controversial. We firstly investigated the role of autophagy in SWH-induced wound closure rate, inflammatory response, and histopathology, utilizing an inhibitor of autophagy 3-methyladenine (3-MA) and its agonist rapamycin (RAP). As expected, we found 3-MA treatment remarkably increased the wound closure rate, combated inflammation response, and mitigated histopathological changes, while RAP delivery aggravated SWH-induced pathological damage. To further exploit the underlying mechanism of autophagy regulating inflammation, the specific inhibitors of yes-associated protein (YAP), Verteporfin, and Anti-IL-33 were applied. Herein, treating with 3-MA markedly suppressed the expression of tumor necrosis factor-α (TNF-α), IL-1ß, and IL-6, promoted that of IL-10, IL-33, and ST2, while RAP administration reverted SWH-induced the up-regulation of these inflammatory cytokines mentioned above. Importantly, Verteporfin administration not only down-regulated the expression levels of YAP, TNF-α, and IL-6 but also up-regulated that of IL-33 and IL-10. Unexpectedly, 3-MA or RAP retreatment did not have any impact on the changes in IL-33 among these inflammatory indicators. Furthermore, elevated expression of IL-33 promoted wound closure and alleviated the pathological damage, whereas, its antagonist Anti-IL-33 treatment overtly reversed the above-mentioned effects of IL-33. Moreover, 3-MA in combination with anti-IL-33 treatment reversed the role of 3-MA alone in mitigated pathological changes, but they failed to revert the effect of anti-IL-33 alone on worsening pathological damage. In sum, emerging data support the novel contribution of the YAP/IL-33 pathway in autophagy inhibition against SWH-induced pathological damage, and highlight that the autophagy/YAP/IL-33 signal axis is expected to become a new therapeutic target for SWH.

Ruxolitinib exerts neuroprotection via repressing ferroptosis in a mouse model of traumatic brain injury.

Traumatic brain injury (TBI) is a major cause of death and disability worldwide. Various forms of cells death are involved in the pathological process of TBI, without exception to ferroptosis, which is mainly triggered by iron-dependent lipid peroxidation. Although there have been studies on ferroptosis and TBI, the effect of ruxolitinib (Ruxo), one type of FDA approved drugs for treating myelofibrosis, on the process of ferroptosis post-TBI is remained non-elucidated. Therefore, using a controlled cortical impact device to establish the mouse TBI model, we examined the effect of Ruxo on TBI-induced ferroptosis, in which the inhibitor of ferroptosis, Ferrostatin-1 (Fer-1) was used as a positive control. Moreover, we also respectively explored the effects of these two interventions on neurological deficits caused by TBI. We firstly examined the expression patterns of ferroptosis-related markers at protein level at different time points after TBI. And based on the expression changes of these markers, we chose 12 h post-TBI to prove the effect of Ruxo on ferroptosis. Importantly, we found the intensely inhibitory effect of Ruxo on ferroptosis, which is in parallel with the results obtained after Fer-1-treatment. In addition, these two treatments both alleviated the content of brain water and degree of neurodegeneration in the acute phase of TBI. Finally, we further confirmed the neuroprotective effect of Ruxo or Fer-1 via the wire-grip test, Morris water maze and open field test, respectively. Thereafter, the lesion volume and iron deposition were also measured to certificate their effects on the long-term outcomes of TBI. Our results ultimately demonstrate that inhibiting ferroptosis exerts neuroprotection, and this is another neuroprotective mechanism of Ruxo on TBI.

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In forensic traumatic pathology practice, immunohistochemistry and special staining technique play an important role in wound age estimation and complications of traumatic complication identification. They even play an important role in the identification of special cases, such as snakebites and insulin killings. This article reviews the application and value of immunohistochemistry and special staining techniques in forensic traumatic pathology based on the cases of forensic practice reported in literature.

Chronic restraint stress exacerbates neurological deficits and disrupts the remodeling of the neurovascular unit in a mouse intracerebral hemorrhage model.

Growing evidences have shown that patients recovering from stroke experience high and unremitting stress. Chronic restraint stress (CRS) has been found to exacerbate neurological impairments in an experimental focal cortical ischemia model. However, there have been no studies reporting the effect and mechanism of CRS on intracerebral hemorrhage (ICH). This study aimed to evaluate the effect of CRS on a mouse ICH model. Adult male C57BL mice were subjected to infusion of collagenase IV (to induce ICH) or saline (for sham) into the left striatum. After ICH, animals were stressed with application of CRS protocol for 21 days. Our results showed that CRS significantly exacerbated neurological deficits (Garcia test, corner turn test, and wire grip test) and the ipsilateral brain atrophy and reduced body weight gain after ICH. Immunofluorescence staining indicated that CRS exerted significant suppressive effects on neuron, astrocyte, vascular endothelial cell and pericyte and excessively activated microglia post ICH. All of the key cellular components mentioned above are involved in the neurovascular unit (NVU) remodeling in the peri-hemorrhagic region after ICH. Western blot results showed that matrix metalloproteinase (MMP)-9 and tight junction (TJ) proteins including zonula occludens-1, occludin and claudin-5 were increased after ICH, but MMP-9 protein was further up-regulated and TJ-related proteins were down-regulated by CRS. In addition, ICH-induced activation of endoplasmic reticulum stress and apoptosis were further strengthened by CRS. Collectively, CRS exacerbates neurological deficits and disrupts the remodeling of the peri-hemorrhagic NVU after ICH, which may be associated with TJ proteins degradation and excessive activation of MMP-9 and endoplasmic reticulum stress-apoptosis.LAY SUMMARYCRS exacerbates neurological deficits and disrupts the remodeling of the NVU in the recovery stage after ICH, which suggest that monitoring chronic stress levels in patients recovering from ICH may merit consideration in the future.