Bexarotene improves motor function after spinal cord injury in mice

Mitophagy in acute central nervous system injuries: regulatory mechanisms and therapeutic potentials

Acute central nervous system injuries, including ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, traumatic brain injury, and spinal cord injury, are a major global health challenge. Identifying optimal therapies and improving the long-term neurological functions of patients with acute central nervous system injuries are urgent priorities. Mitochondria are susceptible to damage after acute central nervous system injury, and this leads to the release of toxic levels of reactive oxygen species, which induce cell death. Mitophagy, a selective form of autophagy, is crucial in eliminating redundant or damaged mitochondria during these events. Recent evidence has highlighted the significant role of mitophagy in acute central nervous system injuries. In this review, we provide a comprehensive overview of the process, classification, and related mechanisms of mitophagy. We also highlight the recent developments in research into the role of mitophagy in various acute central nervous system injuries and drug therapies that regulate mitophagy. In the final section of this review, we emphasize the potential for treating these disorders by focusing on mitophagy and suggest future research paths in this area.

Cadmium induces the secretion of SASP factors regulated by MAPK and NF-κB signaling pathways in HEK293 cells: A possible mechanism of acute kidney damage induced by cadmium

Cadmium (Cd) is a highly toxic environmental pollutant, which can accumulate in the kidney, induce cell damage and trigger inflammatory responses. However, the specific regulation mechanism of nephrotoxicity induced by Cd remains unclear. This study was conducted to investigate the toxic effects of Cd on human embryonic kidney 293 (HEK293) cells and explore its potential mechanisms. Cell viability was assessed with MTT assay. Reactive oxygen species (ROS) levels and mitochondrial membrane potential (MMP) were evaluated through DCFH-DA staining and Rhodamine staining. Apoptosis was detected with Hoechst 33258 staining. The expression of the DNA damage biomarker 8-hydroxy-2'-deoxyguanosine (8-OHdG) was detected with the 8-OHdG ELISA kit. Senescence-associated secretory phenotype (SASP) factors and signaling pathways were analyzed by Western blot. The results showed that Cd exposure could induce oxidative stress and cellular inflammation. It could also impair MMP, contribute to cell apoptosis and activate MAPK and NF-κB signaling pathways. Finally, exposure to Cd triggered DNA damage and SASP production. However, NF-κB inhibitor BAY11-7082 and antioxidant NAC could inhibit these effects by suppressing NF-κB and MAPK signaling pathways. The present study revealed the specific mechanisms of Cd toxicity in HEK293 cells and provided useful information for elucidating the nephrotoxicity of Cd.

Bexarotene ameliorated the pulmonary inflammation and M1 polarization of alveolar macrophages induced by cigarette smoke via PPARγ/HO-1

BACKGROUND

Alveolar macrophages (AMs) modulate pulmonary inflammation in chronic obstructive pulmonary disease (COPD), contributing to its progression. The PPARγ/RXRα heterodimer influences AM polarization induced by cigarette smoke (CS). Although PPARγ agonists suppress CS-induced M1 macrophage polarization, the impact of RXRα agonists on this process has not been determined. This study explored the effects and mechanisms of the RXRα agonist bexarotene on macrophage polarization in a COPD mouse model.

METHODS

C57BL/6 mice were assigned to the control, model, bexarotene, or model + bexarotene group. The COPD model was induced by CS exposure and intraperitoneal injection of cigarette smoke extract (CSE), followed by intraperitoneal administration of bexarotene. Additionally, MH-S cells were exposed to CSE and bexarotene. Lung tissues were subjected to hematoxylin-eosin staining, and emphysema and inflammatory scores were assessed. Cytokine levels and cell differentials in bronchoalveolar lavage fluid were measured, and macrophage polarization was evaluated using immunohistochemistry, flow cytometry, and qPCR.

RESULTS

Bexarotene effectively reduced inflammatory scores, cytokine levels, and neutrophil counts and ameliorated emphysema and M1 polarization of AMs in COPD model mice. Furthermore, while CSE exposure reduced PPARγ expression and the transcriptional activity of AMs, bexarotene enhanced the transcriptional response of PPARγ to CSE. HO-1 was identified as a potential target of PPARγ; its levels were assessed in AMs, revealing that bexarotene mitigated the CSE-induced reduction in HO-1. Notably, the effect of bexarotene was partially inhibited by the PPARγ inhibitor.

CONCLUSIONS

Our results indicated that bexarotene may curb inflammation and M1 polarization in COPD through activation of the PPARγ/HO-1 pathway.

TGN-020 ameliorates motor dysfunction post-spinal cord injury via enhancing astrocyte autophagy and mitigating inflammation by activating AQP4/PPAR-γ/mTOR pathway

Spinal Cord Injury (SCI) is a severe condition that often leads to substantial neurological impairments. This study aimed to explore the role of Aquaporin-4 (AQP4) in regulating astrocyte autophagy and neuroinflammation post-SCI, as well as to evaluate the therapeutic potential of AQP4 inhibition using the specific inhibitor TGN-020. Using Western blot, CCK8 assays, immunofluorescence staining, histopathological assessments, and behavioral analyses, we investigated the effects of TGN-020 on SCI-induced alterations in autophagy, neuroinflammation, astrocyte proliferation, neuronal damage, and motor function recovery in both rat and astrocyte models. Our findings indicate that TGN-020 significantly enhances astrocyte autophagy, reduces neuroinflammation, thereby leading to mitigated astrocyte activation by suppressing AQP4 expression. These beneficial effects are associated with the activation of the peroxisome proliferator-activated receptor-γ/mammalian target of rapamycin (PPAR-γ/mTOR) signaling pathway. Notably, the introduction of the PPAR-γ specific inhibitor GW9662 abrogated the positive regulatory effects of TGN-020 on SCI-induced autophagy and neuroinflammation. Collectively, our in vivo and in vitro experiments demonstrate that TGN-020, by down-regulating AQP4, activates the PPAR-γ/mTOR pathway, ameliorates astrocyte autophagy, diminishes neuroinflammation, and ultimately enhances motor function recovery.

Ruxolitinib improves the inflammatory microenvironment, restores glutamate homeostasis, and promotes functional recovery after spinal cord injury

JOURNAL/nrgr/04.03/01300535-202419110-00030/figure1/v/2024-03-08T184507Z/r/image-tiff The inflammatory microenvironment and neurotoxicity can hinder neuronal regeneration and functional recovery after spinal cord injury. Ruxolitinib, a JAK-STAT inhibitor, exhibits effectiveness in autoimmune diseases, arthritis, and managing inflammatory cytokine storms. Although studies have shown the neuroprotective potential of ruxolitinib in neurological trauma, the exact mechanism by which it enhances functional recovery after spinal cord injury, particularly its effect on astrocytes, remains unclear. To address this gap, we established a mouse model of T10 spinal cord contusion and found that ruxolitinib effectively improved hindlimb motor function and reduced the area of spinal cord injury. Transcriptome sequencing analysis showed that ruxolitinib alleviated inflammation and immune response after spinal cord injury, restored EAAT2 expression, reduced glutamate levels, and alleviated excitatory toxicity. Furthermore, ruxolitinib inhibited the phosphorylation of JAK2 and STAT3 in the injured spinal cord and decreased the phosphorylation level of nuclear factor kappa-B and the expression of inflammatory factors interleukin-1β, interleukin-6, and tumor necrosis factor-α. Additionally, in glutamate-induced excitotoxicity astrocytes, ruxolitinib restored EAAT2 expression and increased glutamate uptake by inhibiting the activation of STAT3, thereby reducing glutamate-induced neurotoxicity, calcium influx, oxidative stress, and cell apoptosis, and increasing the complexity of dendritic branching. Collectively, these results indicate that ruxolitinib restores glutamate homeostasis by rescuing the expression of EAAT2 in astrocytes, reduces neurotoxicity, and effectively alleviates inflammatory and immune responses after spinal cord injury, thereby promoting functional recovery after spinal cord injury.

Non-coding RNAs in the spotlight of the pathogenesis, diagnosis, and therapy of cutaneous T cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is a group of primary and secondary cutaneous malignancies characterized by aberrant T-cells in the skin. Diagnosing CTCL in its early stage can be difficult because of CTCL's ability to mimic benign cutaneous inflammatory skin diseases. CTCL has multiple subtypes with different disease progression and diagnostic parameters despite similar clinical manifestations. The accurate diagnosis and prognosis of a varied range of diseases require the detection of molecular entities to capture the complete footprint of disease physiology. Non-coding RNAs (ncRNAs) have recently been discovered as major regulators of CTCL gene expression. They can affect tumor cell growth, migration, programmed cell death (PCD), and immunoregulation through interactions with the tumor microenvironment (TME), which in turn affect CTCL progression. This review summarizes recent advances in how ncRNAs regulate CTCL cell activity, especially their role in PCD. It also discusses the potential use of ncRNAs as diagnostic and prognostic biomarkers for different subtypes of CTCL. Furthermore, prospective targets and therapeutic approaches influenced by ncRNAs are presented. A better appreciation of the intricate epigenetic landscape of CTCL is expected to facilitate the creation of innovative targeted therapies for the condition.

To re-examine the intersection of microglial activation and neuroinflammation in neurodegenerative diseases from the perspective of pyroptosis

Neurodegenerative diseases (NDs), such as Alzheimer's disease, Parkinson's disease, Huntington's disease, and motor neuron disease, are diseases characterized by neuronal damage and dysfunction. NDs are considered to be a multifactorial disease with diverse etiologies (immune, inflammatory, aging, genetic, etc.) and complex pathophysiological processes. Previous studies have found that neuroinflammation and typical microglial activation are important mechanisms of NDs, leading to neurological dysfunction and disease progression. Pyroptosis is a new mode involved in this process. As a form of programmed cell death, pyroptosis is characterized by the expansion of cells until the cell membrane bursts, resulting in the release of cell contents that activates a strong inflammatory response that promotes NDs by accelerating neuronal dysfunction and abnormal microglial activation. In this case, abnormally activated microglia release various pro-inflammatory factors, leading to the occurrence of neuroinflammation and exacerbating both microglial and neuronal pyroptosis, thus forming a vicious cycle. The recognition of the association between pyroptosis and microglia activation, as well as neuroinflammation, is of significant importance in understanding the pathogenesis of NDs and providing new targets and strategies for their prevention and treatment.