Department of Anatomy & Neurobiology, College of Medicine, Neuroscience Institute, University of Tennessee Health Science Center (UTHSC), Rm 231-Wittenborg bldg., 855 Monroe Ave, Memphis, TN 38163, USA
Dr. Tauheed Ishrat
Department of Anatomy & Neurobiology, College of Medicine, Neuroscience Institute, University of Tennessee Health Science Center (UTHSC), Rm 231-Wittenborg bldg., 855 Monroe Ave, Memphis, TN 38163, USA
Activation of the NOD-like receptor protein (NLRP3)-inflammasome has been postulated to mediate inflammatory responses to brain damage during ischemic/reperfusion (I/R) injury. We therefore hypothesized that MCC950, a selective NLRP3-inflammasome inhibitor provides protection in mouse model of transient middle cerebral artery occlusion (tMCAO). Focal cerebral ischemia was induced by 60 min tMCAO followed by intraperitoneal administration of MCC950 (50 mg/kg) or saline at 1 h and 3 h post-occlusion. After 24 h of I/R, mice were tested for neurological outcome and were sacrificed for the analysis of infarct size and estimating NLRP3-inflammasome and apoptotic markers as well. Spectrophotometric method was used to determine hemoglobin (Hb) content as a marker of intracerebral hemorrhage. MCC950-treated mice showed a substantial reduction in infarction, edema and Hb content compared to saline controls in parallel with improved neurological deficits. MCC950 reduced expression of NLRP3-inflammasome cleavage products Caspase-1 and interlukin-1β (IL-1β) in penumbral region. These protective effects of MCC950 were associated with decreased TNF-α levels as well as poly (ADP-ribose) polymerase (PARP) and Caspase-3 cleavage and paralleled less phosphrylated NFκBp65 and IκBα levels. Taken together, these data indicate that inhibition of NLRP3-inflammasome with MCC950 has therapeutic potential in ischemic stroke models. Further investigations into the therapeutic efficacy and protocols are needed to confirm whether MCC950 treatment could be a promising candidate for clinical trials.
NNucleotide oligomerization domain (NOD)-like receptor protein-3 (NLRP3) inflammasome may intimately contribute to sustaining damage following traumatic brain injury (TBI). This study aims to examine whether specific modulation of NLPR3 inflammasome by MCC950, a novel selective NLRP3 inhibitor confers protection after experimental TBI. Unilateral cortical impact injury was induced in young adult C57BL/6 mice. MCC950 (50 mg/kg, i.p.) or saline was administration at 1 h and 3 h post TBI. Animals were tested for neurological function, and then sacrificed for edema at 24 or 72 h post TBI. Immunoblotting and histological analysis were performed to identify markers of NLRP3 inflammasome and pro-apoptotic activity in peri-contusional areas of the brains at 24 or 72 h post TBI. MCC950 treatment provided a significant improvement in neurological function and reduced cerebral edema in TBI animals. TBI upregulated NLRP3, apoptosis-associated speck-like adapter protein (ASC), cleaved caspase-1 and interlukein-1β (IL-1β) in perilesional area. MCC950 efficiently repressed caspase-1 and IL-1β with a transient effect on ASC and NLRP3 post TBI. MCC950 treatment also provided protection against pro-apoptotic activation of poly (ADP-ribose) polymerase (PARP) and caspase-3 associated with TBI. A concurrent inhibition of inflammasome priming was also detectable at NFk-B-p65 and caspase-1 level. Our findings support the implication of NLRP3 inflammasome in the pathogenesis of TBI, further suggests the therapeutic potential of MCC950.
Alzheimer’s disease (AD) is the most common form of age-associated dementia characterized by amyloid-β plaques and neurofibrillary tangles. Recent studies have demonstrated that thioredoxin-interacting protein (TXNIP), an endogenous regulator of redo
Although the precise mechanisms contributing to secondary brain injury following traumatic brain injury are complex and obscure, a number of studies have demonstrated that inflammatory responses are an obvious and early feature in the pathogenesis of traumatic brain injury. Inflammasomes are multiprotein complexes that prompt the stimulation of caspase-1 and subsequently induce the maturation and secretion of proinflammatory cytokines, such as interleukin-1β and interleukin-18. These cytokines play a pivotal role in facilitating innate immune responses and inflammation. Among various inflammasome complexes, the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome is the best characterized, a crucial role for NLRP3 has been demonstrated in various brain diseases, including traumatic brain injury. Several recent studies have revealed the contribution of NLRP3 inflammasome in identifying cellular damage and stimulating inflammatory responses to aseptic tissue injury after traumatic brain injury. Even more important, blocking or inhibiting the activation of the NLRP3 inflammasome may have substantial potential to salvage tissue damage during traumatic brain injury. In this review, we summarize recently described mechanisms that are involved in the activation and regulation of the NLRP3 inflammasome. Moreover, we review the recent investigations on the contribution of the NLRP3 inflammasome in the pathophysiology of TBI, and current advances and challenges in potential NLRP3-targeted therapies. A significant contribution of NLRP3 inflammasome activation to traumatic brain injury implies that therapeutic approaches focused on targeting specific inflammasome components could significantly improve the traumatic brain injury outcomes.