Fluoxetine reduces organ injury and improves motor function after traumatic brain injury in mice

Hypidone hydrochloride (YL-0919) ameliorates functional deficits after traumatic brain injury in mice by activating the sigma-1 receptor for antioxidation

JOURNAL/nrgr/04.03/01300535-202508000-00023/figure1/v/2024-09-30T120553Z/r/image-tiff Traumatic brain injury involves complex pathophysiological mechanisms, among which oxidative stress significantly contributes to the occurrence of secondary injury. In this study, we evaluated hypidone hydrochloride (YL-0919), a self-developed antidepressant with selective sigma-1 receptor agonist properties, and its associated mechanisms and targets in traumatic brain injury. Behavioral experiments to assess functional deficits were followed by assessment of neuronal damage through histological analyses and examination of blood-brain barrier permeability and brain edema. Next, we investigated the antioxidative effects of YL-0919 by assessing the levels of traditional markers of oxidative stress in vivo in mice and in vitro in HT22 cells. Finally, the targeted action of YL-0919 was verified by employing a sigma-1 receptor antagonist (BD-1047). Our findings demonstrated that YL-0919 markedly improved deficits in motor function and spatial cognition on day 3 post traumatic brain injury, while also decreasing neuronal mortality and reversing blood-brain barrier disruption and brain edema. Furthermore, YL-0919 effectively combated oxidative stress both in vivo and in vitro. The protective effects of YL-0919 were partially inhibited by BD-1047. These results indicated that YL-0919 relieved impairments in motor and spatial cognition by restraining oxidative stress, a neuroprotective effect that was partially reversed by the sigma-1 receptor antagonist BD-1047. YL-0919 may have potential as a new treatment for traumatic brain injury.

Neuroprotective effects of hypidone hydrochloride (YL-0919) after traumatic brain injury in mice

BACKGROUND

Neurological dysfunction is a common complication of traumatic brain injury (TBI), and early treatments are critical for the long-term prognosis. This study aimed to investigate whether hypidone hydrochloride (YL-0919) improves neurological function impairment in mice with TBI.

METHODS

TBI was induced in adult male C57BL/6J mice using the controlled cortical impact (CCI) method. First, the modified neurological severity score (mNSS), rotarod test, and Morris water maze (MWM) test were conducted to assess the impact of YL-0919 on neurological function in mice with TBI. Next, immunofluorescence and laser speckle contrast imaging were utilized to measure the number and activation of microglia and cerebral blood flow (CBF) after TBI. Enzyme-linked immunosorbent assays (ELISAs) were employed to assess the inflammatory factors. Finally, Western blotting was performed to measure the expression of proteins. Golgi-Cox staining was utilized to investigate the structure of pyramidal neurons.

RESULTS

YL-0919 significantly alleviated neurological dysfunction in TBI+YL-0919 mice compared with TBI+Vehicle mice, increased the time spent on the rotarod (F = 1.297, P <0.05), and partially relieved cognitive dysfunction in TBI mice (for mNSS, F = 5.540, P <0.01; for MWM test, F = 30.78, P <0.05). Additionally, YL-0919 effectively inhibited the proliferation and activation of microglia (both P <0.01), promoted the recovery of CBF around the brain injury site and inhibited the expression of tumor necrosis factor-α (F = 9.142, P <0.05) and IL-1β (F = 4.662, P <0.05), and increased the concentration of IL-4 (F = 5.172, P <0.05). Furthermore, continuous gavage of YL-0919 (2.5 mg/kg) for seven days effectively increased the protein expression of brain-derived neurotrophic factor (BDNF), promoted the phosphorylation of mammalian target of rapamycin (mTOR), increased postsynaptic density protein 95 (PSD95) and synapsin1 levels, and increased the neuronal dendritic complexity and the dendritic spine density around the brain injury site (all P <0.05).

CONCLUSIONS

Our findings indicated that YL-0919 can ameliorate neurological dysfunction in mice after TBI through the suppression of inflammation and the stimulation of the BDNF-mTOR signaling pathway. These findings provide an insightful perspective on the potential pharmacological mechanism involved in the neuroprotective effect of YL-0919.

Dysregulated brain-gut axis in the setting of traumatic brain injury: review of mechanisms and anti-inflammatory pharmacotherapies

Traumatic brain injury (TBI) is a chronic and debilitating disease, associated with a high risk of psychiatric and neurodegenerative diseases. Despite significant advancements in improving outcomes, the lack of effective treatments underscore the urgent need for innovative therapeutic strategies. The brain-gut axis has emerged as a crucial bidirectional pathway connecting the brain and the gastrointestinal (GI) system through an intricate network of neuronal, hormonal, and immunological pathways. Four main pathways are primarily implicated in this crosstalk, including the systemic immune system, autonomic and enteric nervous systems, neuroendocrine system, and microbiome. TBI induces profound changes in the gut, initiating an unrestrained vicious cycle that exacerbates brain injury through the brain-gut axis. Alterations in the gut include mucosal damage associated with the malabsorption of nutrients/electrolytes, disintegration of the intestinal barrier, increased infiltration of systemic immune cells, dysmotility, dysbiosis, enteroendocrine cell (EEC) dysfunction and disruption in the enteric nervous system (ENS) and autonomic nervous system (ANS). Collectively, these changes further contribute to brain neuroinflammation and neurodegeneration via the gut-brain axis. In this review article, we elucidate the roles of various anti-inflammatory pharmacotherapies capable of attenuating the dysregulated inflammatory response along the brain-gut axis in TBI. These agents include hormones such as serotonin, ghrelin, and progesterone, ANS regulators such as beta-blockers, lipid-lowering drugs like statins, and intestinal flora modulators such as probiotics and antibiotics. They attenuate neuroinflammation by targeting distinct inflammatory pathways in both the brain and the gut post-TBI. These therapeutic agents exhibit promising potential in mitigating inflammation along the brain-gut axis and enhancing neurocognitive outcomes for TBI patients.

Cognition and Behavior in the Aging Brain Following TBI: Surveying the Preclinical Evidence

Elderly individuals (65 years and older) represent the fastest-growing demographic of new clinical traumatic brain injury (TBI) cases, yet there is a paucity of preclinical research in aged animals. The limited preclinical work available aligns with the clinical literature in that there appear to be significant differences in pathophysiology, recovery potential, and response to medications between animals at different points across the age spectrum. The aim of this review is to discuss the limited studies and highlight critical age-related differences in affective, cognitive, and neurobehavioral deficits, to discuss factors that influence functional outcomes, and to identify targets for future research. The consensus is that aged rodents face challenges related to dysregulated inflammation, reduced neuroplasticity, and age-related cellular changes, which hinder their recovery after TBI. The most successful intervention studies in animal models to date, of the limited array available, have explored interventions targeting inflammatory downregulation. Current standards of neuropsychopharmacology for post-TBI neurocognitive recovery have not been investigated in a significant capacity. In addition, currently available animal models do not sufficiently account for important age-related comorbidities, dual insults, or differences in TBI mechanism of injury in elderly individuals. TBI in the aged population is more likely to lead to additional neurodegenerative diseases that further complicate recovery. The findings underscore the need for tailored therapeutic interventions to improve outcomes in both adult and elderly populations.

Melatonin supplementation protects against traumatic colon injury by regulating SERPINA3N protein expression

Traumatic colon injury (TCI) is a typical injury with high mortality. Prolongation of the intervention time window is a potentially useful approach to improving the outcomes of TCI casualties. This study aimed to identify the pathological mechanisms of TCI and to develop effective strategies to extend the survival time. A semicircular incision was made to prepare a TCI model using C57BL/6 mice. An overview of microbiota dysregulation was achieved by metagenome sequencing. Protein expression reprogramming in the intestinal epithelium was investigated using proteomics profiling. The mice that were subjected to TCI died within a short period of time when not treated. Gut symbiosis showed abrupt turbulence, and specific pathogenic bacteria rapidly proliferated. The protein expression in the intestinal epithelium was also reprogrammed. Among the differentially expressed proteins, SERPINA3N was overexpressed after TCI modeling. Deletion of Serpina3n prolonged the posttraumatic survival time of mice with TCI by improving gut homeostasis in vivo. To promote the translational application of this research, the effects of melatonin (MLT), an oral inhibitor of the SERPINA3N protein, were further investigated. MLT effectively downregulated SERPINA3N expression and mitigated TCI-induced death by suppressing the NF-κB signaling pathway. Our findings prove that preventive administration of MLT serves as an effective regimen to prolong the posttraumatic survival time by restoring gut homeostasis perturbed by TCI. It may become a novel strategy for improving the prognosis of patients suffering from TCI.

The Potential Role of m6A in the Regulation of TBI-Induced BGA Dysfunction

The brain–gut axis (BGA) is an important bidirectional communication pathway for the development, progress and interaction of many diseases between the brain and gut, but the mechanisms remain unclear, especially the post-transcriptional regulation of BGA after traumatic brain injury (TBI). RNA methylation is one of the most important modifications in post-transcriptional regulation. N6-methyladenosine (m⁶A), as the most abundant post-transcriptional modification of mRNA in eukaryotes, has recently been identified and characterized in both the brain and gut. The purpose of this review is to describe the pathophysiological changes in BGA after TBI, and then investigate the post-transcriptional bidirectional regulation mechanisms of TBI-induced BGA dysfunction. Here, we mainly focus on the characteristics of m⁶A RNA methylation in the post-TBI BGA, highlight the possible regulatory mechanisms of m⁶A modification in TBI-induced BGA dysfunction, and finally discuss the outcome of considering m⁶A as a therapeutic target to improve the recovery of the brain and gut dysfunction caused by TBI.