Thioredoxin-Interacting Protein (TXNIP) Knockdown Protects against Sepsis-Induced Brain Injury and Cognitive Decline in Mice by Suppressing Oxidative Stress and Neuroinflammation

Abstract

Sepsis-associated encephalopathy (SAE) is linked to increased morbidity and mortality rates in patients with sepsis. Increased cytokine production and neuronal apoptosis are implicated in the pathogenesis of the SAE. Neuroinflammation plays a major role in sepsis-induced brain injury. Thioredoxin-interacting protein (TXNIP), an inhibitor of thioredoxin, is associated with oxidative stress and inflammation. However, whether the TXNIP is involved in the sepsis-induced brain injury and the underlying mechanism is yet to be elucidated. Therefore, the present study was aimed at elucidating the effects of TXNIP knockdown on sepsis-induced brain injury and cognitive decline in mice. Lipopolysaccharide (LPS) was injected intraperitoneally to induce sepsis brain injury in mice. The virus-carrying control or TXNIP shRNA was injected into the lateral ventricle of the brain 4 weeks before the LPS treatment. The histological changes in the hippocampal tissues, encephaledema, and cognitive function were detected, respectively. Also, the 7-day survival rate was recorded. Furthermore, the alterations in microglial activity, oxidative response, proinflammatory factors, apoptosis, protein levels (TXNIP and NLRP3 inflammasome), and apoptosis were examined in the hippocampal tissues. The results demonstrated that the TXNIP and NLRP3 inflammasome expression levels were increased at 6, 12, and 24 h post-LPS injection. TXNIP knockdown dramatically ameliorated the 7-day survival rate, cognitive decline, brain damage, neuronal apoptosis, and the brain water content, inhibited the activation of microglia, downregulated the NLRP3/caspase-1 signaling pathway, and reduced the oxidative stress and the neuroinflammatory cytokine levels at 24 h post-LPS injection. These results suggested a crucial effect of TXNIP knockdown on the mechanism of brain injury and cognitive decline in sepsis mice via suppressing oxidative stress and neuroinflammation. Thus, TXNIP might be a potential therapeutic target for SAE patients.

FNDC5/irisin mediates hallmark brain alterations and cognitive impairment in acute intestinal injury/disease

“…The supernatant was collected by centrifugation at 4°C and 13000 rpm for 20 min. The levels of IL-1β, TNF-α, and IL-6 in the plasma, hippocampus, and BV2 cells were detected by the ELISA kit [25], according to the manufacturer's instructions (Lianke, Hangzhou, China).…”

“…Superoxide dismutase (SOD) was estimated to evaluate the antioxidant activity. The above assays were conducted using the kits according to the manufacturer's instructions (Meimian, Wuhan, China) and previous ndings [25].…”

“…For quanti cation, four representative images per tissue section over a microscopic eld of 400× and ve representative images per cell slide over a microscopic eld of 200× were averaged. More than 200 cells in each group were evaluated to determine the percentage of TUNEL-positive cells [9,25].…”

“…On the following day, the membranes were washed intensively with TBST buffer and incubated with an anti-rabbit IgG (1:5000, Proteintech, Wuhan, China) or anti-mouse IgG (1:5000, Proteintech, Wuhan, China) secondary antibody at room temperature for 1 h. Finally, the immunoreactive bands were developed using enhanced chemiluminescence reagent and visualized on a protein imaging system. The intensity of each band was analyzed using Image J software [25].…”

“…NLRP3 in ammasome, mainly located in microglia, can regulate the activation of microglia [17][18][19][20], and the activation of microglial NLRP3-ASC in ammasome induces the release of proin ammatory cytokines and chemokines [21]. In recent years, TXNIP/NLRP3 signaling pathway has been deduced to be involved in microglial activation [22,23], and be related to oxidative stress and neuroin ammation in neurological diseases [22,24,25]. However, whether TXNIP is involved in the II/R-induced cognitive de cit and cerebral injury, and whether there is a correlation between FNDC5/irisin and TXNIP is yet to be explored.…”