TREM2 alleviates white matter injury after traumatic brain injury in mice might be mediated by regulation of DHCR24/LXR pathway in microglia.

BACKGROUND: White matter injury (WMI) is an important pathological process after traumatic brain injury (TBI). The correlation between white matter functions and the myeloid cells expressing triggering receptor-2 (TREM2) has been convincingly demonstrated. Moreover, a recent study revealed that microglial sterol metabolism is crucial for early remyelination after demyelinating diseases. However, the potential roles of TREM2 expression and microglial sterol metabolism in WMI after TBI have not yet been explored. METHODS: Controlled cortical injury was induced in both wild-type (WT) and TREM2 depletion (TREM2 KO) mice to simulate clinical TBI. COG1410 was used to upregulate TREM2, while PLX5622 and GSK2033 were used to deplete microglia and inhibit the liver X receptor (LXR), respectively. Immunofluorescence, Luxol fast blue staining, magnetic resonance imaging, transmission electron microscopy, and oil red O staining were employed to assess WMI after TBI. Neurological behaviour tests and electrophysiological recordings were utilized to evaluate cognitive functions following TBI. Microglial cell sorting and transcriptomic sequencing were utilized to identify alterations in microglial sterol metabolism-related genes, while western blot was conducted to validate the findings. RESULTS: TREM2 expressed highest at 3 days post-TBI and was predominantly localized to microglial cells within the white matter. Depletion of TREM2 worsened aberrant neurological behaviours, and this phenomenon was mediated by the exacerbation of WMI, reduced renewal of oligodendrocytes, and impaired phagocytosis ability of microglia after TBI. Subsequently, the upregulation of TREM2 alleviated WMI, promoted oligodendrocyte regeneration, and ultimately facilitated the recovery of neurological behaviours after TBI. Finally, the expression of DHCR24 increased in TREM2 KO mice after TBI. Interestingly, TREM2 inhibited DHCR24 and upregulated members of the LXR pathway. Moreover, LXR inhibition could partially reverse the effects of TREM2 upregulation on electrophysiological activities. CONCLUSIONS: We demonstrate that TREM2 has the potential to alleviate WMI following TBI, possibly through the DHCR24/LXR pathway in microglia.

Remote Ischemic Post-conditioning Reduces Cognitive Impairment in Rats Following Subarachnoid Hemorrhage: Possible Involvement in STAT3/STAT5 Phosphorylation and Th17/Treg Cell Homeostasis.

The inflammatory response following subarachnoid hemorrhage (SAH) may lead to Early Brain Injury and subsequently contribute to poor prognosis such as cognitive impairment in patients. Currently, there is a lack of effective strategies for SAH to ameliorate inflammation and improve cognitive impairment in clinical. This study aims to examine the inhibitory impact of remote ischemic post-conditioning (RIPostC) on the body's inflammatory response by regulating Th17/Treg cell homeostasis after SAH. The ultimate goal is to search for potential early treatment targets for SAH. The rat SAH models were made by intravascular puncture of the internal carotid artery. The intervention of RIPostC was administered for three consecutive days immediately after successful modeling. Behavioral experiments including the Morris water maze and Y-maze tests were conducted to assess cognitive functions such as spatial memory, working memory, and learning abilities 2 weeks after successful modeling. The ratio of Th17 cells and Treg cells in the blood was detected using flow cytometry. Immunofluorescence was used to observe the infiltration of neutrophils into the brain. Signal transducers and activators of transcription 5 (STAT5) and signal transducers and activators of transcription 3 (STAT3) phosphorylation levels, receptor-related orphan receptor gamma-t (RORγt), and forkhead box protein P3 (Foxp3) levels were detected by Western blot. The levels of anti-inflammatory factors (IL-2, IL-10, IL-5, etc.) and pro-inflammatory factors (IL-6, IL-17, IL-18, TNF-α, IL-14, etc.) in blood were detected using Luminex Liquid Suspension Chip Assay. RIPostC significantly improved the cognitive impairment caused by SAH in rats. The results showed that infiltration of Th17 cells and neutrophils into brain tissue increased after SAH, leading to the release of pro-inflammatory factors (IL-6, IL-17, IL-18, and TNF-α). This response can be inhibited by RIPostC. Additionally, RIPostC facilitates the transfer of Treg from blood to the brain and triggers the release of anti-inflammatory (IL-2, IL-10, and IL-5) factors to suppress the inflammation following SAH. Finally, it was found that RIPostC increased the phosphorylation of STAT5 while decreasing the phosphorylation of STAT3. RIPostC reduces inflammation after SAH by partially balancing Th17/Treg cell homeostasis, which may be related to downregulation of STAT3 and upregulation of STAT5 phosphorylation, which ultimately alleviates cognitive impairment in rats. Targeting Th17/Treg cell homeostasis may be a promising strategy for early SAH treatment.

Exosomal LncRNA TM7SF3-AU1 Aggravates White Matter Injury via MiR-702-3p/SARM1 Signaling After Subarachnoid Hemorrhage in Rats.

Subarachnoid hemorrhage (SAH) is a devastating disease associated with a high mortality and morbidity. Exosomes have been considered as a potential therapeutic target for SAH. However, the effect of exosomes in SAH remains to be elucidated. In this study, we focused on investigating the effect of plasma exosomal lncRNA TM7SF3-AU1 in white matter injury after SAH. The SAH model was established by means of endovascular perforation. Exosomes were extracted from rat plasma samples. The expression of RNAs in the exosomes was detected by the transcriptomic microarray. Differentially expressed circRNA, lncRNA, and mRNA were obtained. The ceRNA network showed that the lncRNA TM7SF3-AU1 and miR-702-3p were closely associated with SARM1. Knocking down TM7SF3-AU1 promoted the expression of miR-702-3p and suppressed the expression of SARM1, and knocking down TM7SF3-AU1 also attenuated white matter injury after SAH. In addition, knocking down TM7SF3-AU1 improved the neurological deficits in locomotion, anxiety, learning, memory, and electrophysiological activity after SAH. Mechanistically, TM7SF3-AU1 was able to absorb miR-702-3p, which directly bind the SARM1 mRNA. Furthermore, the white matter injury attenuated by knockdown of TM7SF3-AU1 was partially reversed by the miR-702-3p antagomir in SAH rats. Taken together, this study showed that TM7SF3-AU1 acts as a sponge for miR-702-3p, reducing the inhibitory effect of miR-702-3p on SARM1, resulting in increased SARM1 expression and thus leading to white matter injury after SAH. Our study provides new insights into exosome-associated white matter injury. It also highlights TM7SF3-AU1 as a potential therapeutic target for white matter injury after SAH.

Essential role of MALAT1 in reducing traumatic brain injury.

As a highly evolutionary conserved long non-coding RNA, metastasis associated lung adenocarcinoma transcript 1 (MALAT1) was first demonstrated to be related to lung tumor metastasis by promoting angiogenesis. To investigate the role of MALAT1 in traumatic brain injury, we established mouse models of controlled cortical impact and cell models of oxygen-glucose deprivation to mimic traumatic brain injury in vitro and in vivo. The results revealed that MALAT1 silencing in vitro inhibited endothelial cell viability and tube formation but increased migration. In MALAT1-deficient mice, endothelial cell proliferation in the injured cortex, functional vessel density and cerebral blood flow were reduced. Bioinformatic analyses and RNA pull-down assays validated enhancer of zeste homolog 2 (EZH2) as a downstream factor of MALAT1 in endothelial cells. Jagged-1, the Notch homolog 1 (NOTCH1) agonist, reversed the MALAT1 deficiency-mediated impairment of angiogenesis. Taken together, our results suggest that MALAT1 controls the key processes of angiogenesis following traumatic brain injury in an EZH2/NOTCH1-dependent manner.

PTEN and AKT/GSK-3ß/CRMP-2 signaling pathway are involved in neuronal apoptosis and axonal injury in early brain injury after SAH in rats.

In early brain injury (EBI) after subarachnoid hemorrhage (SAH), white matter (WM) axonal injury plays a key role in the prognosis of the disease. The purpose of this study was to investigate the effects of phosphatase and tensin homolog deleted on chromosome ten (PTEN) on axonal injury and neuronal apoptosis post-SAH in rats and to find its underlying mechanism. Adeno-associated virus was injected into the lateral ventricle to suppress or promote PTEN. Neural function post-SAH in animals was determined by the modified Garcia score, beam balance, and Rotarod test, and the blood-brain barrier disruption was assessed by the brain water content. Axonal injury post-SAH was observed by TEM and determined by IF, and neuron apoptosis was measured by TUNEL staining. The mechanism was analyzed by Western blot to detect p-PTEN/PTEN, p-AKT/AKT, p-GSK-3ß/GSK-3ß, p-CRMP-2/CRMP-2, axonal injury marker ß-APP and pro- and anti-apoptosis proteins, including Bax and Bcl-2, expression. We found 1. After knocking down PTEN, neuronal apoptosis and axonal injury were alleviated, and nerve function and blood-brain barrier were protected; accordingly, after overexpression of PTEN, neuronal apoptosis and axon damage were aggravated, and nerve function damage and blood-brain barrier damage were increased. 2. PTEN and AKT/GSK-3ß/CRMP-2 pathway were jointly involved in regulating neuronal apoptosis and WM axon injury after SAH. According to our research, PTEN was a negative factor of EBI, and together with the AKT/GSK-3ß/CRMP-2 signaling pathway aggravates neuronal apoptosis and WM axon damage after SAH. Inhibition of PTEN expression may become a new target for SAH treatment.

5-Lipoxygenase inhibition reduces inflammation and neuronal apoptosis via AKT signaling after subarachnoid hemorrhage in rats.

Early brain injury (EBI) is a major contributor to the high mortality and morbidity after subarachnoid hemorrhage (SAH). Inflammatory responses and neuronal apoptosis are important causes of EBI. Because 5- lipoxygenase (5-LOX) is known to be involved various central nervous system diseases, we investigated the effects of 5-LOX inhibition during EBI after SAH. Zileuton and LY294002 were used to inhibit expression of 5-LOX and Akt, respectively. We found that 5-LOX expression was significantly increased in the cytoplasm of cortical neurons after SAH and was accompanied by upregulated expression of the inflammatory factors LTB4, TNF-α, IL-1ß and IL-6; upregulation of the pro-apoptotic factor Bax; downregulation of the anti-apoptotic factor Bcl-2; and an increased apoptosis rate. Gastric Zileuton administration significantly suppressed all of those effects and improved neurological function. Zileuton also upregulated activated (phosphorylated) AKT levels, and these beneficial effects of Zileuton were abolished by intracerebroventricular infusion of the PI3K inhibitor LY294002. Taken together, these findings indicate that 5-LOX mediates pro-inflammatory and pro-apoptotic effects that contribute to EBI after SAH and that those effects are suppressed by activation of PI3K/Akt signaling. This suggests targeting 5-LOX may be an effective approach to treating EBI after SAH.

Nampt promotes osteogenic differentiation and lipopolysaccharide-induced interleukin-6 secretion in osteoblastic MC3T3-E1 cells.

The Nicotinamide phosphoribosyltransferase (Nampt)-NAD-Sirt1 pathway modulates processes involved in the pathogenesis of multiple diseases by influencing inflammation. This study aimed to explore the effect of Nampt in osteogenic differentiation and inflammatory response of osteoblastic MC3T3-E1 cells. We developed an in vitro model of lipopolysaccharide (LPS)-induced inflammation and showed that Nampt and Sirt1 were significantly upregulated in LPS-treated MC3T3-E1 cells. LPS induced secretion of the proinflammatory cytokine interleukin-6 (IL-6) and attenuated osteogenic differentiation. Then we transfected cells with adenoviruses to knock down or over express Nampt. Nampt promoted the expression of IL-6, TAK1 and phospho-NF-κB p65 after LPS treatment. Overexpression of Nampt overrode the effect of LPS and rescued LPS-induced inhibition on osteogenic differentiation. FK866, a Nampt inhibitor, had the same inhibitory effect as Nampt knockdown. In addition, Sirt1 suppression by EX527 decreased IL-6 secretion and NF-κB activation without changing the level of Nampt. EX527 also decreased osteogenic differentiation. Incubation with NMN or SRT 1720 also counteract the inhibitory effect of LPS and rescued osteoblast differentiation. Therefore, we demonstrated that Nampt acted both in promoting osteoblast differentiation and in enhancing inflammatory response, mediated by Sirt1 in MC3T3-E1 cells.

ETAR silencing ameliorated neurovascular injury after SAH in rats through ERK/KLF4-mediated phenotypic transformation of smooth muscle cells.

Subarachnoid haemorrhage (SAH) is a devastating cerebrovascular disease which has a high morbidity and mortality. The phenotypic transformation of smooth muscle cells (SMCs) lead to neurovascular injury after SAH. However, the underlying mechanism remains unclear. In the present study, we aimed to investigate the potential role of ET-1/ETAR on the phenotypic transformation of SMCs after SAH. The models of SAH were established in vivo and vitro. We observed ET-1 secretion by endothelial cells was increased, and the phenotypic transformation of SMCs was aggravated after SAH. Knocking down ETAR inhibited the phenotypic transformation of SMCs, decreased the migration ability of SMCs in vitro. Moreover, Knocking down ETAR ameliorated cerebral ischaemia and alleviated dysfunction of neurological function in vivo. In addition, Exogenous ET-1 increased the migration ability of SMCs and aggravated the phenotypic transformation of SMCs in vitro, which were partly reversed by the antagonist of Erk1/2 - SCH772984. Taken together, our results demonstrated that endothelial ET-1 aggravated the phenotypic transformation of SMCs after SAH. Knocking down ETAR inhibited the phenotypic transformation of SMCs through ERK/KLF4 thus ameliorating neurovascular injury after SAH. We also revealed that ET-1/ETAR is a potential therapeutic target after SAH.

Bexarotene promotes microglia/macrophages - Specific brain - Derived Neurotrophic factor expression and axon sprouting after traumatic brain injury.

Traumatic brain injury (TBI) has been regarded as one of the leading cause of injury-related death and disability. White matter injury after TBI is characterized by axon damage and demyelination, resulting in neural network impairment and neurological deficit. Brain-derived neurotrophic factor (BDNF) can promote white matter repair. The activation of peroxisome proliferator-activated receptor gamma (PPARγ) has been reported to promote microglia/macrophages towards anti-inflammatory state and therefore to promote axon regeneration. Bexarotene, an agonist of retinoid X receptor (RXR), can activate RXR/PPARγ heterodimers. The aim of the present study was to identify the effect of bexarotene on BDNF in microglia/macrophages and axon sprouting after TBI in mice. Bexarotene was administered intraperitoneally in C57BL/6 mice undergoing controlled cortical impact (CCI). PPARγ dependency was determined by intraperitoneal administration of a PPARγ antagonist T0070907. We found that bexarotene promoted axon regeneration indicated by increased growth associated protein 43 (GAP43) expression, myelin basic protein (MBP) expression, and biotinylated dextran amine (BDA)+ axon sprouting. Bexarotene also increased microglia/macrophages-specific brain derived neurotrophic factor (BDNF) expression after TBI. In addition, bexarotene reduced the number of pro-inflammatory microglia/macrophages while increased the number of anti-inflammatory microglia/macrophages after TBI. Moreover, bexaortene inhibited pro-inflammatory cytokine secretion. In addition, bexarotene treatment improved neurological scores and cognitive function of CCI-injured mice. These effects of bexarotene were partially abolished by T0070907. In conclusion, bexarotene promotes axon sprouting, increases microglia/macrophages-specific BDNF expression, and induces microglia/macrophages from a pro-inflammatory state towards an anti-inflammatory one after TBI at least partially in a PPARγ-dependent manner.

Pioglitazone ameliorates neuronal damage after traumatic brain injury via the PPARγ/NF-κB/IL-6 signaling pathway.

Traumatic brain injury (TBI) is the major cause of high mortality and disability rates worldwide. Pioglitazone is an activator of peroxisome proliferator-activated receptor-gamma (PPARγ) that can reduce inflammation following TBI. Clinically, neuroinflammation after TBI lacks effective treatment. Although there are many studies on PPARγ in TBI animals, only few could be converted into clinical, since TBI mechanisms in humans and animals are not completely consistent. The present study, provided a potential theoretical basis and therapeutic target for neuroinflammation treatment after TBI. First, we detected interleukin-6 (IL-6), nitric oxide (NO) and Caspase-3 in TBI clinical specimens, confirming a presence of a high expression of inflammatory factors. Western blot (WB), quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC) were used to detect PPARγ, IL-6, and p-NF-κB to identify the mechanisms of neuroinflammation. Then, in the rat TBI model, neurobehavioral and cerebral edema levels were investigated after intervention with pioglitazone (PPARγ activator) or T0070907 (PPARγ inhibitor), and PPARγ, IL-6 and p-NF-κB were detected again by qRT-PCR, WB and immunofluorescence (IF). The obtained results revealed that: 1) increased expression of IL-6, NO and Caspase-3 in serum and cerebrospinal fluid in patients after TBI, and decreased PPARγ in brain tissue; 2) pioglitazone could improve neurobehavioral and reduce brain edema in rats after TBI; 3) the protective effect of pioglitazone was achieved by activating PPARγ and reducing NF-κB and IL-6. The neuroprotective effect of pioglitazone on TBI was mediated through the PPARγ/NF-κB/IL-6 pathway.

Anti-high mobility group box-1 antibody attenuated vascular smooth muscle cell phenotypic switching and vascular remodelling after subarachnoid haemorrhage in rats.

Although cerebral vascular smooth muscle cell (VSMC) phenotypic switching is involved in the vascular dysfunction after subarachnoid haemorrhage (SAH), the precise mechanisms are still unclear. High mobility group box-1 (HMGB1) has been identified as a modulator in VSMC proliferation. The purpose of this study was to investigate the potential role of HMGB1 in the VSMC phenotypic switching following SAH. An endovascular perforation SAH model was used in our experiments. The expression levels of HMGB1, α-smooth muscle actin (α-SMA), osteopontin (OPN), smooth muscle myosin heavy chain (SM-MHC), embryonic smooth muscle myosin heavy chain (Smemb), TXA2, PAR-1 and AT1 receptor were evaluated by Western blot analyses. Iba1-positive cells and apoptotic cells were determined by immunofluorescence staining and TUNEL staining, respectively. Vasoconstriction of the isolated basilar artery was stimulated by thrombin and KCl. We found that HMGB1 expression was markedly increased following SAH, and anti-HMGB1 mAb significantly reversed VSMC phenotypic switching and vascular remodelling in rats. However, the effects of HMGB1 on VSMC phenotypic switching were partly blocked in the presence of SC79, a potent activator of phosphatidylinositol-3-kinase-AKT (PI3K/AKT). Furthermore, the enhanced vasoconstriction and decreased cerebral cortical blood flow induced by SAH were reversed by anti-HMGB1 mAb. Finally, we found that anti-HMGB1 mAb attenuated microglial activation and brain oedema, ameliorating neurological dysfunction. These results indicated that HMGB1 is a useful regulator of VSMC phenotypic switching and vascular remodelling following SAH and might be exploited as a novel therapeutic target for delayed cerebral ischaemia.

High expression of ID1 facilitates metastasis in human osteosarcoma by regulating the sensitivity of anoikis via PI3K/AKT depended suppression of the intrinsic apoptotic signaling pathway.

A lack of understanding of the molecular basis underlying the regulation of metastatic disease and its effective therapy are the primary causes of high mortality in osteosarcoma. Thus, new insights into metastases and novel effective targets for metastatic osteosarcoma are urgently required. Anoikis resistance is considered a hallmark of cancer cells with metastatic ability. However, the molecular mechanism of anoikis is poorly understood in osteosarcoma. We applied immunohistochemistry to investigate the correlation between inhibitor of differentiation or DNA binding 1 (ID1) and clinicopathological features, and investigated the correlation between ID1 and the metastatic behavior of osteosarcoma cells, in vitro and in vivo. The results revealed that ID1 is overexpressed in human osteosarcoma tissues, is positively associated with lung metastases, and is a potential biomarker of poor prognosis. Overexpression of ID1 could increase anoikis insensitivity of osteosarcoma cells to facilitate metastasis through the PI3K/AKT-dependent mitochondrial apoptosis pathway. Knockdown of ID1 partly reversed the high potential of metastasis in anoikis-resistant osteosarcoma cells. Our findings revealed, that ID1 is a candidate molecular target for metastatic potential osteosarcoma by highlighting the role of anoikis resistance. In addition ID1 might be a potential predictor of poor prognosis in patients with osteosarcoma.

Bexarotene Exerts Protective Effects Through Modulation of the Cerebral Vascular Smooth Muscle Cell Phenotypic Transformation by Regulating PPARγ/FLAP/LTB4 After Subarachnoid Hemorrhage in Rats.

Vascular smooth muscle cells (VSMCs) play an important role after a subarachnoid hemorrhage (SAH). The changes in VSMCs following bexarotene treatment after SAH are unknown. In the present study, neurological impairment, decreased cerebral cortical blood flow and transformation of cerebral VSMCs from a contractile to a synthetic phenotype were observed after SAH. Bexarotene reduced neurological impairment, improved cerebral cortical blood flow, inhibited VSMC phenotypic transformation and suppressed the expression of 5-lipoxygenase-activating protein (FLAP) and leukotriene B4 (LTB4), which was partly reversed by GW9662, an inhibitor of peroxisome proliferator-activated receptor gamma (PPARγ). Mechanistically, sh-PPARγ-mediated phenotypic transformation of VSMCs was partially suppressed by MK886, an antagonist of FLAP. Therefore, we conclude that bexarotene reduced neurological impairment, improved cerebral cortical blood flow and inhibited the VSMC phenotypic transformation after SAH, which was achieved by activating PPARγ-mediated inhibition of FLAP/LTB4 in VSMCs.

LXA4 ameliorates cerebrovascular endothelial dysfunction by reducing acute inflammation after subarachnoid hemorrhage in rats.

Lipoxin A4 (LXA4) has been reported to reduce inflammation in experimental subarachnoid hemorrhage (SAH), but the mechanism remains unclear. In this study, we investigated the role of LXA4 in inflammation-mediated cerebrovascular endothelial dysfunction and the potential mechanism after SAH. SAH was induced by endovascular perforation in male Sprague-Dawley rats, and recombinant LXA4 was injected intracerebroventricularly 1.5 h after the operation. The expression changes in the markers of endothelial dysfunction (endothelial microparticles and nitric oxide) were analyzed by flow cytometry or Nitric Oxide (NO) assay kit. Microflow in the cerebral cortex was assayed by laser speckle contrast imaging. Neutrophil infiltration was observed by a marker of leukocyte activity (myeloperoxidase, MPO) that colocalized with a specific marker of endothelial cells (von Willebrand factor, VWF). The expression of LXA4 and its downstream molecules, formyl peptide receptor 2 (FPR2), extracellular signal-regulated kinase (ERK1/2), nuclear factor-κB (NF-κB), matrix metalloproteinase-9 (MMP9), and the levels of pro-inflammatory cytokines (TNF-α, IL-1ß, IL-6), leukocyte adhesion molecule (intercellular adhesion molecule-1, ICAM-1) and MPO were measured either by Western blot or enzyme-linked immunosorbent assay (ELISA). SAH resulted in endothelial dysfunction and a reduction in microflow in the cerebral cortex. The expression of LXA4 was decreased, and the expression of pro-inflammatory factors (NF-κB, MMP9, ICAM-1, MPO) and cytokines (TNF-α, IL-1ß, IL-6) was increased after SAH. The administration of LXA4 significantly ameliorated endothelial dysfunction, recovered microflow, and suppressed the inflammation and infiltration of neutrophils in SAH rats. The underlying mechanism of this outcome may involve the LXA4/FPR2/ERK1/2 pathway. LXA4 might be a promising candidate for acute SAH treatment.

TSSC3 promotes autophagy via inactivating the Src-mediated PI3K/Akt/mTOR pathway to suppress tumorigenesis and metastasis in osteosarcoma, and predicts a favorable prognosis.

BACKGROUND: Over the last two or three decades, the pace of development of treatments for osteosarcoma tends has been slow. Novel effective therapies for osteosarcoma are still lacking. Previously, we reported that tumor-suppressing STF cDNA 3 (TSSC3) functions as an imprinted tumor suppressor gene in osteosarcoma; however, the underlying mechanism by which TSSC3 suppresses the tumorigenesis and metastasis remain unclear. METHODS: We investigated the dynamic expression patterns of TSSC3 and autophagy-related proteins (autophagy related 5 (ATG5) and P62) in 33 human benign bone tumors and 58 osteosarcoma tissues using immunohistochemistry. We further investigated the correlations between TSSC3 and autophagy in osteosarcoma using western blotting and transmission electronic microscopy. CCK-8, Edu, and clone formation assays; wound healing and Transwell assays; PCR; immunohistochemistry; immunofluorescence; and western blotting were used to investigated the responses in TSSC3-overexpressing osteosarcoma cell lines, and in xenografts and metastasis in vivo models, with or without autophagy deficiency caused by chloroquine or ATG5 silencing. RESULTS: We found that ATG5 expression correlated positively with TSSC3 expression in human osteosarcoma tissues. We demonstrated that TSSC3 was an independent prognostic marker for overall survival in osteosarcoma, and positive ATG5 expression associated with positive TSSC3 expression suggested a favorable prognosis for patients. Then, we showed that TSSC3 overexpression enhanced autophagy via inactivating the Src-mediated PI3K/Akt/mTOR pathway in osteosarcoma. Further results suggested autophagy contributed to TSSC3-induced suppression of tumorigenesis and metastasis in osteosarcoma in vitro and in vivo models. CONCLUSIONS: Our findings highlighted, for the first time, the importance of autophagy as an underlying mechanism in TSSC3-induced antitumor effects in osteosarcoma. We also revealed that TSSC3-associated positive ATG5 expression might be a potential predictor of favorable prognosis in patients with osteosarcoma.

Clinical and Basic Evaluation of the Prognostic Value of Uric Acid in Traumatic Brain Injury.

Background: As a major antioxidant in serum, uric acid (UA) was once considered only as the leading cause of gout; however, recent studies have validated its neuroprotective role in ischemic stroke. Because the potential protective effects of UA in traumatic brain injury (TBI) remain largely unknown, this study investigated the role of UA in TBI in both clinical patients and experimental animals. Methods: In TBI patients, serum UA concentrations were measured within 3 days after injury. Clinical outcomes at discharge were classified according to the Glasgow Outcome Scale: good outcome (4-5) and poor outcome (1-3). Risk factors for good outcome were identified via backward logistic regression analysis. For the animal study, a controlled cortical impact (CCI) injury model was established in mice. These mice were given UA at different doses intraperitoneally, and subsequent UA concentrations in mouse serum and brain tissue were determined. Neurological function, oxidative stress, inflammatory response, neuronal maintenance, cerebral blood flow, and lesion size were also assessed. Results: The serum UA level was significantly lower in TBI patients who had a good outcome (P<0.01), and low serum UA was an independent predictor of good outcome after TBI (P<0.01; odds ratio, 0.023; 95% confidence interval, 0.006-0.082). Consistently, decreased levels of serum UA were observed in both TBI patients and CCI animals (P<0.05), whereas the UA concentration was increased in CCI brain tissue (P<0.05). Administration of UA further increased the UA level in brain tissue as compared to that in control animals (P<0.05). Among the different doses administered, 16 mg/kg UA improved sensorimotor functional recovery, spatial learning, and memory in CCI mice (P<0.05). Moreover, oxidative stress and the inflammatory response were inhibited by UA treatment (P<0.05). UA treatment also improved neuronal maintenance and cortical blood flow (P<0.05) but not lesion size (P>0.05). Conclusions: UA acted to attenuate neuronal loss, cerebral perfusion impairment and neurological deficits in TBI mice through suppression of neuronal and vascular oxidative stress. Following TBI, active antioxidant defense in the brain may result in consumption of UA in the serum, and thus, a decreased serum UA level could be predictive of good clinical recovery.

Evolution of cerebral perfusion in the peri-contusional cortex in mice revealed by in vivo laser speckle imaging after traumatic brain injury.

The role of the cerebrovascular network during the acute and chronic phases after traumatic brain injury (TBI) is poorly defined and emerging evidence suggests that cerebral perfusion is altered. The purpose of this study is to explore how the cortical blood flow is pathologically altered following TBI using a newly developed technique, laser speckle imaging. The controlled cortical impact (CCI) model was established in mice. Then, cerebral blood flow was monitored in vivo laser speckle imaging and vessel painting was labeled by Lectin in the peri-contusional cortex. Lastly, mice were assessed for lesion size and neurological functions. Our results indicated that: 1) In the acute phase of TBI, cerebral blood flow and microvessel counts decreased significantly (P < 0.05) 2) In the chronic phase of TBI, cerebral blood flow and microvessel counts recovered gradually (P < 0.05) 3) Cortical lesion volume reduced significantly in the chronic phase of TBI (P < 0.05) 4) Spontaneous neurocognitive recovery occurred following CCI in mice (P < 0.05). In the acute phase of TBI, there is a reduction in cerebral perfusion at the lesion site. However, this reduction recovers in the chronic phase of TBI ultimately, followed by an improvement of ameliorated neurobehavioral functions and a decrease in the lesion size. The novel approach for cerebral blood flow monitoring by laser speckle imaging can be extended from bench to bedside and provide potential therapeutic strategies for TBI patients.

Bexarotene protects against neurotoxicity partially through a PPARγ-dependent mechanism in mice following traumatic brain injury.

Traumatic brain injury (TBI) causes a high rate of mortality and disability worldwide, and there exists almost none effective drugs to protect against TBI. Neurotoxicity occurring after TBI can be derived from microglia and astrocytes, and causes neuronal death and synapse loss. Bexarotene has been demonstrated to protect neurons in CNS diseases. In the present study, we aimed to investigate the potential role of bexarotene in protecting against neurotoxicity after TBI, as well as the underlying mechanism. The controlled cortical impact (CCI) model was established on adult C57BL/6 mice, followed by intraperitoneal administration of bexarotene for 14 consecutive days. We found that bexarotene improved sensorimotor function and cognitive recovery in CCI mice. In addition, bexarotene decreased neuronal death and synapse loss, as well as inhibited apoptotic cascade. Moreover, bexarotene treatment reduced M1 microglia polarization, microglia-derived pro-inflammatory cytokines, and the number of A1 astrocytes after CCI. These effects of bexarotene were partially abolished by T0070907, an antagonist of peroxisome proliferator-activated receptor gamma (PPARγ). Additionally, bexarotene enhanced nuclear translocation and transcriptional activity of PPARγ. These findings show that bexarotene inhibits neurotoxicity in mice after TBI, at least in part through a PPARγ-dependent mechanism.

Significant Injury of the Mammillothalamic Tract without Injury of the Corticospinal Tract After Aneurysmal Subarachnoid Hemorrhage: A Retrospective Diffusion Tensor Imaging Study.

OBJECTIVE: Little is known about the pathophysiologic mechanisms of white matter injury after aneurysmal subarachnoid hemorrhage (aSAH). The purpose of this study is to investigate whether the mammillothalamic tract (MTT) or corticospinal tract (CST) is more affected by aSAH in the same patients with good outcome (Grade 5 on Glasgow Outcome Scale at 3 months) using diffusion tensor imaging (DTI). METHODS: Between June 2013 and September 2016, 21 patients with aSAH with good outcome and 21 sex- and age-matched normal healthy control participants were recruited. DTI was obtained at 8.92 ± 2.4 weeks after onset. Moreover, reconstruction of the CST and the MTT was completed with DTI-studio software. Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were measured. In addition, the motricity index and Mini-Mental State Examination scores were obtained. RESULTS: There was no statistically significant difference detected in the ADC and FA values of the CST between the patient and control groups (P > 0.05). On the contrary, there was a statistically significant difference in ADC and FA values of the MTT between the patient and control groups (P < 0.05). In addition, in the patient group, no correlation (P > 0.05) was observed between motricity index scores and DTI parameters (ADC and FA), whereas the Mini-Mental State Examination showed a positive correlation with FA (r = 0.591, P = 0.029) without correlation to ADC (r = 0.142, P = 0.628). CONCLUSIONS: Patients with good outcomes (Grade 5 on Glasgow Outcome Scale at 3 months) after aSAH appeared to suffer an injury of the MTT without an associated injury of the CST compared with the control group. This injury showed a correlation with cognitive dysfunction.