Activation of cyclin D1 affects mitochondrial mass following traumatic brain injury

Abstract

Cell cycle activation has been associated with varying types of neurological disorders including brain injury. Cyclin D1 is a critical modulator of cell cycle activation and upregulation of Cyclin D1 in neurons contributes to the pathology associated with traumatic brain injury (TBI). Mitochondrial mass is a critical factor to maintain the mitochondrial function, and it can be regulated by different signaling cascades and transcription factors including NRF1. However, the underlying mechanism of how TBI leads to impairment of mitochondrial mass following TBI remains obscure. Our results indicate that augmentation of CyclinD1 attenuates mitochondrial mass formation following TBI. To elucidate the molecular mechanism, we found that Cyclin D1 interacts with a transcription factor NRF1 in the nucleus and prevents NRF1’s interaction with p300 in the pericontusional cortex following TBI. As a result, the acetylation level of NRF1 was decreased, and its transcriptional activity was attenuated. This event leads to a loss of mitochondrial mass in the pericontusional cortex following TBI. Intranasal delivery of Cyclin D1 RNAi immediately after TBI rescues transcriptional activation of NRF1 and recovers mitochondrial mass after TBI.

Aberrant ER Stress Induced Neuronal-IFNβ Elicits White Matter Injury Due to Microglial Activation and T-Cell Infiltration after TBI

“…The Committee on Animal Use for Research and Education at the University of Pittsburgh approved all animal studies, in compliance with National Institutes of Health guidelines. TBI was elicited by unilateral controlled cortical impact (CCI), as previously described (Fox et al, 1998) with little modification (Farook et al, 2013;Kapoor et al, 2013;Sen and Sen, 2016;Saha et al, 2018). Briefly, 8-to 10-week-old adult male or female C57BL/6 mice (The Jackson Laboratory) were randomly assigned to the CCI or sham injury group for all the experiments.…”

“…CXCL10-siRNA or PERK-siRNA (Santa Cruz Biotechnology) were administered to 8-to 10-week-old C57BL/6J mice through an intranasal route using in vivo JetPEI (Polyplus) transfection reagent as described previously with modifications (Bitko and Barik, 2008;Rodriguez et al, 2017;Saha et al, 2018). The siRNA-JetPEI complex was prepared according to the manufacturer's protocol with modifications (Bitko and Barik, 2008;Rodriguez et al, 2017;Saha et al, 2018). Briefly, either the CXCL10 siRNA or PERK siRNA or control siRNA along with JetPEI were separately diluted into half the injection volume in a 10% sterile glucose solution where the final glucose concentration would have to be 5%.…”

“…Western blot and co-IP. The pericontusional cortex was isolated and, lysates were prepared as described before to perform Western blot (WB) and coimmunoprecipitation (co-IP; Farook et al, 2013;Kapoor et al, 2013;Sen and Sen, 2016;Saha et al, 2018). Blots were incubated overnight at 4°C in primary antibody for phospho and total-PERK (Abcam; 1:500), phospho-IRF3 (Cell Signaling Technology; 1:500), phospho-TBK1 (Cell Signaling Technology; 1:500), TBK1 (Santa Cruz Biotechnology; 1:500), phospho-NFB p65 (Ser 536; (zcomSanta Cruz Biotechnology; 1:500 dilution), phospho-Stat3 (Santa Cruz Biotechnology; 1:500 dilution), phospho-Stat6 (Santa Cruz Biotechnology; 1:500 dilution), phospho-Stat1 (Santa Cruz Biotechnology; 1:500 dilution), STING (Millipore; 1:500 dilution), STING (Phospho-Ser366; Affinity Biosciences; 1:500 dilution), or Actin (Sigma-Aldrich; 1:5000 dilution) followed by incubation with a LI-COR IRDye secondary antibody at room temperature.…”

“…The detailed information about the antibodies used for the Western blot analysis is included in Table 1. Blots were visualized using an LI-COR Odyssey imager, and ImageJ software was used to determine the intensity of each band, and the changes in the band-intensity were represented as a fold-change as described previously (Farook et al, 2013;Kapoor et al, 2013;Sen and Sen, 2016;Saha et al, 2018). For Co-IP, cortex collected from all set of experiments were homogenized in lysis buffer [50 mM Tris, pH 7.4, 150 mM NaCl, 0.5% (v/v) Tween 20, 50 mM Tris, pH 7.5, 1 mM EDTA with protease and phosphatase inhibitor] by passage through a 26-gauge needle, and 400 g of the total protein for each sample were incubated overnight with STING (Millipore; 1:100) antibody for overnight.…”

Mitochondrial Dysfunction in Traumatic Brain Injury: Management Strategies

“…Free radicals, which under physiological conditions are involved in inflammatory processes, as well as in learning and memory, 5 its excessive production induces a state of oxidative stress carrying out the progressive deterioration of proteins, alteration in the permeability of the cellular membrane as mitochondrial, alteration of signaling pathways, and damage to the genetic material. [7][8][9] In TBI, clinically, biomarkers characteristic of mitochondrial dysfunction can be identified after 30 minutes, which indicates an increase in proton conductance through the inner membrane of the mitochondria, in turn indicating the onset of a mitochondrial permeability transition; 10 and thus, the increase in mitochondrial Ca 2+ uptake overwhelms the mitochondria causing the activation of nitric oxide synthase (NOS) inducing a mitochondrial production of nitric oxide (NO), as well as the escape of superoxide radicals (O 2 ). These two free radicals rapidly react with each other to form a peroxynitrite (PN) anion that reacts with carbon dioxide to generate more free radicals, responsible for activating a series of pathological processes which will trigger oxidative damage mediated by the peroxidation of susceptible lipids (polyunsaturated fatty acids) of the mitochondrial membrane and inhibition of the electron chain.…”