Injury In Adult Mice Research Articles

Cdk1 Deficiency Extends the Postnatal Window of Cardiomyocyte Proliferation and Restores Cardiac Function after Myocardial Infarction.

Cyclin-dependent kinase 1 (Cdk1) is a master regulator of the G2-M transition between DNA replication and cell division. This study investigates the regulation of cardiomyocyte (CM) proliferation during the early neonatal period and following ischemic injury in adult mice. We analyzed cell cycle dynamics with the assessment of DNA synthesis, and cytokinesis in murine hearts during the first 15 days after birth. A distinct proliferative block was observed at 1 day, followed by a second wave of DNA synthesis at 4 days, leading to CM binucleation (CMBN) by day 5. Genome-wide mRNA profiling revealed the differential expression of cell cycle regulatory genes during this period, with a downregulation of factors involved in cell division and mitosis. The loss of Cdk1 impaired CMBN but extended the neonatal CM proliferation window until day 10 post-birth. In adult hearts, the cardiac-specific ablation of Cdk1 triggered CM proliferation post-myocardial-infarction (MI) in specific zones, driven by the activation of EGFR1 signaling and suppression of the anti-proliferative p38 and p53 signaling. This was accompanied by restoration of fractional shortening, mitochondrial function, and decreased reactive oxygen species. Additionally, cardiac hypertrophy was mitigated, and survival rates post-MI were increased in Cdk1-knockout mice. These findings reveal a novel role of Cdk1 in regulating cell cycle exit and re-entry in differentiated CMs and offer insights into potential strategies for cardiac repair.

MiR-96-5p alleviates cerebral ischemia-reperfusion injury in mice by inhibiting pyroptosis via downregulating caspase 1

Ischemic stroke is one of the leading causes of global mortality and disability. Nevertheless, successful treatment remains limited. In this study, we investigated the efficacy and the mechanism of miR-96-5p in protecting acute ischemic brain injury in adult mice. Focal cerebral ischemia was induced by middle cerebral artery occlusion (MCAO) in adult male C57BL/6 mice. MiR-96-5p or the negative control was administered via intracerebroventricular injection. The expression of pyroptosis-related genes and activation of various resident cells in the brain was assessed by RT-qPCR, western blot, immunohistochemistry, and immunofluorescence. Modified neurological severity score, rotarod test, cylinder test, brain water content, and cerebral infarction volume were used to evaluate the behavioral deficits and the severity of brain injury after MCAO. Flow cytometry, TUNEL staining, and Nissl staining were employed to assess the neuron damage. MiR-96-5p decreased markedly in the ischemic stroke model in vivo and in vitro. MiR-96-5p mimics suppressed the expression of caspase 1 and alleviated the apoptosis rate in OGD/R treatment N2a cells, however, the miR-96-5p inhibitor caused the opposite results. Intracerebroventricular delivery of miR-96-5p agomir significantly mitigated behavioral deficits, brain water content, and cerebral infarction volume after MCAO. In addition, treatment with miR-96-5p agomir downregulated the expression of caspase 1/cleaved caspase 1 and Gsdmd/Gsdmd-N, while alleviating the neuron damage. In summary, overexpression of miR-96-5p suppresses pyroptosis and reduces brain damage in the acute phase of ischemic stroke, providing new insight into the treatment of acute ischemic stroke.

Myelin repair of spinal cord injury in adult mice induced by treadmill training upregulated peroxisome proliferator-activated receptor gamma coactivator 1 alpha.

Growing evidence has proven the efficacy of physical exercise in remyelination and motor function performance after spinal cord injury (SCI). However, the molecular mechanisms of treadmill training on myelin repair and functional recovery after SCI have not yet been fully studied. Here, we explored the effect of treadmill training on upregulating peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α)-mediated myelin repair and functional recovery in a mouse model of thoracic T10 contusion injury. A 4-week treadmill training scheme was conducted on mice with SCI. The expression levels of oligodendrogenesis-related protein and PGC1α were detected by immunofluorescence, RNA fluorescence in situ hybridization and western blotting. Transmission electron microscopy (TEM) was used to observe myelin structure. The Basso Mouse Scale (BMS) and CatWalk automated gait analysis system were used for motor function recovery evaluation. Motor evoked potentials (MEPs) were also identified. In addition, adeno-associated virus (AAV)-mediated PGC1α knockdown in OLs was used to further unravel the role of PGC1α in exercise-induced remyelination. We found that treadmill training boosts oligodendrocyte precursor cells (OPCs) proliferation, potentiates oligodendrocytes (OLs) maturation, and increases myelin-related protein and myelin sheath thickness, thus impelling myelin repair and hindlimb functional performance as well as the speed and amplitude of nerve conduction after SCI. Additionally, downregulating PGC1α through AAV attenuated these positive effects of treadmill training. Collectively, our results suggest that treadmill training enhances remyelination and functional recovery by upregulating PGC1α, which should provide a step forward in the understanding of the effects of physical exercise on myelin repair.

Prenatal alcohol exposure promotes NLRP3 inflammasome-dependent immune actions following morphine treatment and paradoxically prolongs nerve injury-induced pathological pain in female mice.

Neuroimmune dysregulation from prenatal alcohol exposure (PAE) may contribute to neurological deficits associated with fetal alcohol spectrum disorders (FASD). PAE is a risk factor for developing peripheral immune and spinal glial sensitization and release of the proinflammatory cytokine IL-1β, which lead to neuropathic pain (allodynia) from minor nerve injury. Although morphine acts on μ-opioid receptors, it also activates immune receptors, TLR4, and the NLRP3 inflammasome that induces IL-1β. We hypothesized that PAE induces NLRP3 sensitization by morphine following nerve injury in adult mice. We used an established moderate PAE paradigm, in which adult PAE and non-PAE control female mice were exposed to a minor sciatic nerve injury, and subsequent allodynia was measured using the von Frey fiber test. In control mice with standard sciatic damage or PAE mice with minor sciatic damage, the effects of the NLRP3 inhibitor, MCC950, were examined during chronic allodynia. Additionally, minor nerve-injured mice were treated with morphine, with or without MCC950. Invitro studies examined the TLR4-NLRP3-dependent proinflammatory response of peripheral macrophages to morphine and/or lipopolysaccharide, with or without MCC950. Mice with standard sciatic damage or PAE mice with minor sciatic damage developed robust allodynia. Blocking NLRP3 activation fully reversed allodynia in both control and PAE mice. Morphine paradoxically prolonged allodynia in PAE mice, while control mice with minor nerve injury remained stably non-allodynic. Allodynia resolved sooner in nerve-injured PAE mice without morphine treatment than in morphine-treated mice. MCC950 treatment significantly shortened allodynia in morphine-treated PAE mice. Morphine potentiated IL-1β release from TLR4-activated PAE immune cells, while MCC950 treatment greatly reduced it. In female mice, PAE prolongs allodynia following morphine treatment through NLRP3 activation. TLR4-activated PAE immune cells showed enhanced IL-1β release with morphine via NLRP3 actions. Similar studies are needed to examine the adverse impact of morphine in males with PAE. These results are predictive of adverse responses to opioid pain therapeutics in individuals with FASD.

Extracellular RNAs/TLR3 signaling contributes to acute intestinal injury induced by intestinal ischemia reperfusion in mice

Toll-like receptor 3 (TLR3), one pattern recognition receptor activated by viral and endogenous RNA, has been recently reported to regulate ischemia/reperfusion (I/R) injury in various organs. However, the role of TLR3 in the development of intestinal I/R injury remains unclear. The aim of this study is to evaluate the effects of extracellular RNAs/TLR3 signaling in intestinal I/R injury. An intestinal I/R injury model was established with superior mesenteric artery occlusion both in wild-type and TLR3 knockout (KO, −/−) mice, and MODE-K cells were subjected to hypoxia/reoxygenation (H/R) to mimic the I/R model in vivo. Extracellular RNAs (exRNAs), especially double-stranded RNAs (dsRNAs) co-localized with TLR3, were significantly increased both in vitro and in vivo. Compared with wild-type mice, TLR3 knockout obviously attenuated intestinal I/R injury. Both TLR3/dsRNA complex inhibitor and TLR3 siRNA administration reduced TLR3 expressions and subsequently inhibited intestinal inflammatory cytokine production and apoptosis. In conclusion, exRNAs/TLR3 signaling is a key mechanism that regulates intestinal I/R injury in adult mice, and the TLR3/dsRNA complex inhibitor can be an effective approach for attenuating intestinal I/R-induced inflammatory response and apoptosis.

Aging and TNF induce premature senescence of astrocytes after spinal cord injury via regulating YAP expression

BackgroundSpinal cord injury (SCI) causes chronic functional impairment in patients. In addition, SCI is tormenting more and more older adults, and those who suffer from SCI often have shorter lifespans. Previous studies have confirmed that overexpression of p75 leads to neuroinflammation and motor dysfunction following spinal cord injury in adult mice. MethodsAs TNF-α is upregulated after SCI, targeting TNF-mediated inflammation may be an attractive option to combat trauma, paving the way for new therapeutic insight. In this study, we evaluated behavioral testing, phenotype of senescent cells, reactive oxygen species (ROS), inflammation and mitochondrial damage in adult (2-month-old) and aged (20-month-old) female wild-type (WT) and p75 knockout (KO) mice. ResultsHerein, we hypothesized that aged mice were more prone to death after SCI, but p75 deletion could promote motor/sensory function recovery and improve survival in both adult and aged mice. Further exploration of the underlying mechanism revealed that the expression of p-YAP was reduced in vivo and in vitro, and p75 deletion partially rescued aging-induced astrocytes senescence. ConclusionTaken together, our study have identified an unrecognized function of the p75-YAP pathway on preventing astrocytic aging in vitro and in vivo, which may provide further insights and new targets into slowing spinal cord aging and improving dysfunctional remission and longevity.

Early DNase-I therapy delays secondary brain damage after traumatic brain injury in adult mice

Traumatic brain injury (TBI) causes the release of danger-associated molecular patterns (DAMP) from damaged or dead cells, which contribute to secondary brain damage after TBI. Cell-free DNA (cfDNA) is a DAMP known to cause disruption of the blood–brain barrier (BBB), promote procoagulant processes, brain edema, and neuroinflammation. This study tested the hypothesis that administration of deoxyribonuclease-I (DNase-I) has a beneficial effect after TBI. Mice (n = 84) were subjected to controlled cortical impact (CCI) and posttraumatic intraperitoneal injections of low dose (LD) or high dose (HD) of DNase-I or vehicle solution at 30 min and 12 h after CCI. LD was most effective to reduce lesion volume (p = 0.003), brain water content (p < 0.0001) and to stabilize BBB integrity (p = 0.019) 1 day post-injury (dpi). At 6 h post injury LD-treated animals showed less cleavage of fibrin (p = 0.0014), and enhanced perfusion as assessed by micro-computer-tomography (p = 0.027). At 5 dpi the number of Iba1-positive cells (p = 0.037) were reduced, but the number of CD45-positive cells, motoric function and brain lesion volume was not different. Posttraumatic-treatment with DNase-I therefore stabilizes the BBB, reduces the formation of brain edema, immune response, and delays secondary brain damage. DNase-I might be a new approach to extend the treatment window after TBI.

Ligand-Induced Activation of GPR110 (ADGRF1) to Improve Visual Function Impaired by Optic Nerve Injury

It is extremely difficult to achieve functional recovery after axonal injury in the adult central nervous system. The activation of G-protein coupled receptor 110 (GPR110, ADGRF1) has been shown to stimulate neurite extension in developing neurons and after axonal injury in adult mice. Here, we demonstrate that GPR110 activation partially restores visual function impaired by optic nerve injury in adult mice. Intravitreal injection of GPR110 ligands, synaptamide and its stable analogue dimethylsynaptamide (A8) after optic nerve crush significantly reduced axonal degeneration and improved axonal integrity and visual function in wild-type but not gpr110 knockout mice. The retina obtained from the injured mice treated with GPR110 ligands also showed a significant reduction in the crush-induced loss of retinal ganglion cells. Our data suggest that targeting GPR110 may be a viable strategy for functional recovery after optic nerve injury.

Chronic juvenile stress exacerbates neurobehavioral dysfunction and neuroinflammation following traumatic brain injury in adult mice.

Chronic stress in adolescence may affect brain maturation and predispose individuals to psychiatric disorders in adulthood. However, whether chronic juvenile stress influences vulnerability to nonpsychiatric brain injuries, such as traumatic brain injury (TBI), remains unclear. Therefore, we hypothesized that juvenile stress-related neuronal circuit disturbances could aggravate brain damage following TBI in adulthood. For chronic stress, we used an unpredictable chronic mild stress (UCMS) procedure for 5 weeks in adolescent mice. This was followed by a controlled cortical impact (CCI) injury to evaluate the influence of chronic juvenile stress on brain damage progression following TBI in adult mice. Mice underwent UCMS alone, UCMS followed by CCI, CCI alone, or sham operation. We characterized neurobehavioral deficits (Barnes maze, open field, and light-dark tests), neuroinflammation (ionized calcium-binding adapter molecule 1 [Iba-1], glial fibrillary acidic protein [GFAP], and neuron-specific nuclear protein [NeuN] immunoreactivity), and apoptosis (B-cell lymp [Bcl-2], Bcl-2-associated X protein [Bax], and procaspase-3 immunoreactivity). Following CCI, mice exposed to UCMS showed decreased spatial learning and memory in the Barnes maze test compared with unstressed mice. A significant increase in Iba-1, GFAP, and Bax/Bcl-2 immunostaining levels was observed in the mice exposed to UCMS followed by CCI compared with the CCI-only mice. In contrast, a significant decrease in NeuN immunostaining levels was observed in the UCMS with CCI group compared with the CCI alone group. Chronic stress in a juvenile mouse model aggravates neurobehavioral impairments and potentiates glial reactivity, neuronal injury, and apoptosis following moderate-to-severe TBI that occurs in adulthood. The present study suggests that juvenile chronic stress may influence poor outcomes following TBI in later adulthood.

Effects of task-based rehabilitative training combined with PTEN/SOCS3 coinhibition promotes axon regeneration and upper extremity skilled motor function recovery after cervical spinal cord injury in adult mice

Previous studies reported that the codeletion of PTEN and SOCS3 can greatly enhance the capacity of axon regeneration after central nervous system (CNS) injury. Moreover, the promotion of functional recovery can be improved by rehabilitative training under a use-dependent plasticity mechanism after CNS injury. However, few studies have reported the interaction between these mechanisms after spinal cord injury (SCI). Therefore, we investigated the combined effects of PTEN/SOCS3 coinhibition and rehabilitative training on axon regeneration and upper extremity motor functional improvement after cervical SCI in mice. In this study, we used RNA interference viruses to coinhibit PTEN and SOCS3 and induced a C5 crush injury on the side of preference. The injured upper extremity was trained by single pellet grasping for 4 weeks. We found that the coinjection of viruses significantly increased the expression of p-S6 and p-STAT in the cortex, reduced the dieback pattern of injured axons and promoted traced axon regeneration. More importantly, combination therapy further enhanced axon regeneration compared with PTEN/SOCS3 coinhibition alone. In behavioral tests, the motor performance of the mice in the PTEN/SOCS3 + Training group was better than that of the mice in the other groups. These results indicate that combining task-based rehabilitative training with PTEN/SOCS3 coinhibition further promotes axon regeneration and significant improvement in forelimb skilled motor function after cervical SCI. Our findings provide new therapeutic insights into SCI treatment.

Molecular mechanisms of lesion-induced axonal sprouting in the corticofugal projection: the role of glial cells.

Molecular mechanisms of lesion-induced axonal sprouting in the corticofugal projection: the role of glial cells.

Anti‐CD3 mAb Induced Necrotizing Enterocolitis in Formula‐Fed Neonatal Mice through a Gut Microbiome Colonization Dependent Mechanism

Necrotizing enterocolitis (NEC) is a serious disease that affects the small intestine of premature infants. Previous studies showed that formula feeding is a risk factor for NEC. Furthermore, gut microbiome and T cells are revealed to play a critical role in the pathogenesis of NEC. It has been reported that anti‐CD3 mAb induces T cell activation and small intestinal injury in adult mice. However, how the small intestine of neonatal mice responses to anti‐CD3 mAb treatment is uncertain. In the present study, we aimed to study the susceptibility of dam‐fed and formula‐fed neonatal mice to the anti‐CD3 mAb challenge. For this purpose, mouse pups (P0) were nursed by dam feeding (DF) and formula feeding (FF) respectively. On postnatal day 2, pups were subjected to subcutaneous treatment with 10 mg/kg anti‐CD3ε mAb. They were processed to measure intestinal permeability to FITC‐dextran and euthanized at 24 h after administration of anti‐CD3 mAb. Histology examination showed that FF but not DF pups developed NEC‐like injury in the small intestine after anti‐CD3 treatment. FF Pups were noted to display an increase in mortality, intestinal permeability, and inflammatory mediators upon anti‐CD3 mAb challenge compared to DF pups. Even though the inflammatory markers were increased, the intestinal mucosa in DF pups remains intact after being challenged with anti‐CD3. Remarkably, disruption of postnatal colonization by gavaging streptomycin attenuated NEC incidence in anti‐CD3 mAb‐treated FF pups, suggesting that bacterial colonization plays a role in predisposition of mouse pups by formula feeding to anti‐CD3 mAb‐induced intestinal injury. Taken together, this study provided the first evidence that anti‐CD3 mAb induces NEC‐like injury in neonatal mice receiving FF but not in DF via a microbiome colonization dependent manner. The underlying mechanisms regarding this pathophysiological event are to be studied in the future.

JNK1-Dependent Phosphorylation of GAP-43 Serine 142 is a Novel Molecular Marker for Axonal Growth.

Mammalian axon growth has mechanistic similarities with axon regeneration. The growth cone is an important structure that is involved in both processes, and GAP-43 (growth associated protein-43kDa) is believed to be the classical molecular marker. Previously, we used growth cone phosphoproteomics to demonstrate that S96 and T172 of GAP-43 in rodents are highly phosphorylated sites that are phosphorylated by c-jun N-terminal protein kinase (JNK). We also revealed that phosphorylated (p)S96 and pT172 antibodies recognize growing axons in the developing brain and regenerating axons in adult peripheral nerves. In rodents, S142 is another putative JNK-dependent phosphorylation site that is modified at a lower frequency than S96 and T172. Here, we characterized this site using a pS142-specific antibody. We confirmed that pS142 was detected by co-expressing mouse GAP-43 and JNK1. pS142 antibody labeled growth cones and growing axons in developing mouse neurons. pS142 was sustained until at least nine weeks after birth in mouse brains. The pS142 antibody could detect regenerating axons following sciatic nerve injury in adult mice. Comparison of amino acid sequences indicated that rodent S142 corresponds to human S151, which is predicted to be a substrate of the MAPK family, which includes JNK. Thus, we confirmed that the pS142 antibody recognized human phospho-GAP-43 using activated JNK1, and also that its immunostaining pattern in neurons differentiated from human induced pluripotent cells was similar to those observed in mice. These results indicate that the S142 residue is phosphorylated by JNK1 and that the pS142 antibody is a new candidate molecular marker for axonal growth in both rodents and human.

The Involvement of Long Non-coding RNA and Messenger RNA Based Molecular Networks and Pathways in the Subacute Phase of Traumatic Brain Injury in Adult Mice.

Traumatic brain injury (TBI) is a complex injury with a multi-faceted recovery process. Long non-coding RNAs (lncRNAs) are demonstrated to be involved in central nervous system (CNS) disorders. However, the roles of lncRNAs in long-term neurological deficits post-TBI are poorly understood. The present study depicted the microarray’s lncRNA and messenger RNA (mRNA) profiles at 14 days in TBI mice hippocampi. LncRNA and mRNA microarray was used to identify differentially expressed genes. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to validate the microarray results. Bioinformatics analysis [including Gene Ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, lncRNA-mRNA co-expression network, and lncRNA-miRNA-mRNA network] were applied to explore the underlying mechanism. A total of 264 differentially expressed lncRNAs and 232 expressed mRNAs were identified (fold change > 1.5 and P-value < 0.05). Altered genes were enriched in inflammation, immune response, blood–brain barrier, glutamatergic neurological effects, and neuroactive ligand-receptor, which may be associated with TBI-induced pathophysiologic changes in the long-term neurological deficits. The lncRNAs-mRNAs co-expression network was generated for 74 lncRNA-mRNA pairs, most of which are positive correlations. The lncRNA-miRNA-mRNA interaction network included 12 lncRNAs, 59 miRNAs, and 25 mRNAs. Numerous significantly altered lncRNAs and mRNAs in mice hippocampi were enriched in inflammation and immune response. Furthermore, these dysregulated lncRNAs and mRNAs may be promising therapeutic targets to overcome obstacles in long-term recovery following TBI.

Cyclooxygenase-2 deficiency attenuates lipopolysaccharide-induced inflammation, apoptosis, and acute lung injury in adult mice.

Many lung diseases are caused by an excessive inflammatory response, and inflammatory lung diseases are often modeled using lipopolysaccharide (LPS) in mice. Cyclooxygenase-2 (COX-2) encoded by the Ptgs2 gene is induced in response to inflammatory stimuli including LPS. The objective of this study was to test the hypothesis that mice deficient in COX-2 (Ptgs2-/-) will be protected from LPS-induced lung injury. Wild-type (WT; CD1 mice) and Ptgs2-/- mice (on a CD1 background) were treated with LPS or vehicle for 24 h. LPS treatment resulted in histological evidence of lung injury, which was attenuated in the Ptgs2-/- mice. LPS treatment increased the mRNA levels for tumor necrosis factor-α, interleukin-10, and monocyte chemoattractant protein-1 in the lungs of WT mice, and the LPS-induced increases in these levels were attenuated in the Ptgs2-/- mice. The protein levels of active caspase-3 and caspase-9 were lower in the LPS-treated lungs of Ptgs2-/- mice than in LPS-treated WT mice, as were the number of terminal deoxynucleotide transferase dUTP nick end labeling-positive cells in lung sections. LPS exposure resulted in a greater lung wet-to-dry weight ratio (W/D) in WT mice, suggestive of pulmonary edema, while in LPS-treated Ptgs2-/- mice, the W/D was not different from controls and less than in LPS-treated WT mice. These results demonstrate that COX-2 is involved in the inflammatory response to LPS and suggest that COX-2 not only acts as a downstream participant in the inflammatory response, but also acts as a regulator of the inflammatory response likely through a feed-forward mechanism following LPS stimulation.

Gallic acid ameliorates di-(2-ethylhexyl) phthalate-induced testicular injury in adult mice.

Background: Di-(2-ethylhexyl) phthalate (DEHP) is a well-known endocrine-disrupting compound inducing degeneration of testes. Gallic acid (GA) is a polyphenol with various pharmacological properties, including antioxidant and anti-inflammatory effects.Purpose: This research evaluated effects of different doses of GA on DEHP-induced testicular injury in adult mice.Research Design: Male mice were randomly divided into five groups and treated with agents for two weeks; group (I) received normal saline and corn oil (5mL/kg/day, p. o.), group (II) received DEHP (2g/kg/day, dissolved in corn oil, p. o.), groups (III, IV, and V) received DEHP + GA (25, 50, and 100mg/kg/day, p. o.). Body and testes weights, serum testosterone, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels were evaluated. The number of sperms and sperm motility and viability were analyzed in the cauda epididymis. Histological changes, oxidative/nitrosative stress markers, and inflammatory cytokines levels were examined in testes.Results: Body and testes weights, the number of spermatogonia, primary spermatocyte and early spermatid, and late spermatid and sperm vitality, and progressive motility were significantly reduced in mice exposed to DEHP. Serum testosterone level decreased and serum LH and FSH levels increased in DEHP-exposed mice. These alterations were associated with the increased oxidative stress level and inflammatory responses in testicular tissue. Treatment with GA (50 and 100mg/kg/day) attenuated DEHP-induced alterations in oxidative stress markers and inflammatory cytokines and reversed abnormality in sperm characteristic and number, tissue structure, and serum hormones levels.Conclusions: Results indicated that GA might be a promising agent against male gonadal toxicity induced by endocrine disrupting chemicals including DEHP.

Serine/Threonine-Protein Kinase 3 Facilitates Myocardial Repair After Cardiac Injury Possibly Through the Glycogen Synthase Kinase-3β/β-Catenin Pathway.

BackgroundThe neonatal heart maintains its entire regeneration capacity within days after birth. Using quantitative phosphoproteomics technology, we identified that SGK3 (serine/threonine‐protein kinase 3) in the neonatal heart is highly expressed and activated after myocardial infarction. This study aimed to uncover the function and related mechanisms of SGK3 on cardiomyocyte proliferation and cardiac repair after apical resection or ischemia/reperfusion injury.Methods and ResultsThe effect of SGK3 on proliferation and oxygen glucose deprivation/reoxygenation– induced apoptosis in isolated cardiomyocytes was evaluated using cardiomyocyte‐specific SGK3 overexpression or knockdown adenovirus5 vector. In vivo, gain‐ and loss‐of‐function experiments using cardiomyocyte‐specific adeno‐associated virus 9 were performed to determine the effect of SGK3 in cardiomyocyte proliferation and cardiac repair after apical resection or ischemia/reperfusion injury. In vitro, overexpression of SGK3 enhanced, whereas knockdown of SGK3 decreased, the cardiomyocyte proliferation ratio. In vivo, inhibiting the expression of SGK3 shortened the time window of cardiac regeneration after apical resection in neonatal mice, and overexpression of SGK3 significantly promoted myocardial repair and cardiac function recovery after ischemia/reperfusion injury in adult mice. Mechanistically, SGK3 promoted cardiomyocyte regeneration and myocardial repair after cardiac injury by inhibiting GSK‐3β (glycogen synthase kinase‐3β) activity and upregulating β‐catenin expression. SGK3 also upregulated the expression of cell cycle promoting genes G1/S‐specific cyclin‐D1, c‐myc (cellular‐myelocytomatosis viral oncogene), and cdc20 (cell division cycle 20), but downregulated the expression of cell cycle negative regulators cyclin kinase inhibitor P 21 and cyclin kinase inhibitor P 27.ConclusionsOur study reveals a key role of SGK3 on cardiac repair after apical resection or ischemia/reperfusion injury, which may reopen a novel therapeutic option for myocardial infarction.

Effect of Zinc on Lead Acetate Induced Liver and Stomach Injury in Adult Mice: Electron microscopic and Biochemical Study

Effect of Zinc on Lead Acetate Induced Liver and Stomach Injury in Adult Mice: Electron microscopic and Biochemical Study

PPARɣ Agonist Pioglitazone and Synthetic Surfactant Protein B Mimic B‐YL Prevents Hyperoxia‐Induced Lung Injury in Adult Mice

Purpose of Study Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS) are serious conditions and often life threatening. ALI and ARDS are characterized by acute alveolar injury, disrupted epithelial-mesenchymal signaling, oxidative stress, and surfactant dysfunction. Previously we demonstrated that perturbation in TGF-β and wingless/Int (Wnt) signaling pathways, known to be involved in perinatal lung development and hyperoxia-induced rat lung injury, was ameliorated by pioglitazone and B-YL, a novel synthetic surfactant, in neonatal rats. However, whether this approach can be extended to be effective in adult lung injury is unknown. We hypothesize that by stabilizing alveolar homeostasis, combined PPARγ agonist PGZ and oxidant resistant synthetic surfactant B-YL can be a unified approach to block hyperoxia-induced lung injury not only in neonates but also in adults. Methods Used 3 to 6 months old C57BL/6 adult mice lungs were harvested. Lung explants were placed in 15% FBS/Weymouth medium and exposed ex-vivo to 21% or 95% O2 for 24 or 72h. Treatment groups included: 1) untreated control; 2) B-YL (100 mg/kg); 3) PGZ (1 mg/kg); and 4) B-YL (100 mg/kg)+PGZ (1 mg/kg). Wnt signaling (LEF-1 and β-catenin), TGF-β signaling (Alk5 and SMAD3), and apoptosis (BAX) markers were determined by Western analysis. Inflammatory cytokines (IL6, IL1β, TNFα, and MCP1) were measured by qRT-PCR. Summary of Results Hyperoxia exposure resulted in significant increases in lung injury and apoptosis markers including the upregulation of Wnt and TGF-β pathway proteins. PGZ+ B-YL treated group showed significant amelioration of hyperoxia-induced alterations in these injury markers, including Wnt (LEF-1 and β-catenin) and TGF-β (ALK-5) pathway proteins (vs. 95% O2 control group). Similarly, hyperoxia-induced increases in IL6, IL1β, TNFα, and MCP1 were blocked in B-YL alone, as well as PGZ+B-YL treated groups. Conclusions Effectiveness of combined PGZ+B-YL in blocking hyperoxia- induced lung injury ex-vivo sets the stage to test this therapeutic approach for adult lung injury in vivo.

Combining task-based rehabilitative training with PTEN inhibition promotes axon regeneration and upper extremity skilled motor function recovery after cervical spinal cord injury in adult mice

BackgroundConditional deletion of Pten in corticospinal neurons promotes axon sprouting and regeneration after spinal cord injury (SCI). However, regeneration studies targeted on PTEN inhibition seldom show motor function recovery. The promotion of functional recovery can be improved by rehabilitative training under a use-dependent plasticity mechanism. PurposeTo investigate the combined effects of PTEN inhibition and rehabilitative training on axon regeneration and subsequent motor functional improvement after cervical spinal cord injury. MethodsLentiviral particles (Lenti-PTEN-RNAi or Lenti-Scrambled-EGFP) were injected into the right sensorimotor mouse cortex in four experimental groups (PTEN RNAi + Training, PTEN RNAi, Control + Training, Control). Two weeks after injection, all mouse groups received a left C5 crush injury. We performed task-based rehabilitative training for 4 weeks on the PTEN RNAi + Training and Control + Training groups. Biotinylated dextran amine (BDA) was used for anterograde tracing of the dorsal corticospinal tract (dCST). We analysed axonal regeneration through immunohistochemical methods. A battery of behavioral tests was employed to assess functional recovery at Day3 and every other week after injury. ResultsCombining rehabilitative training with PTEN inhibition induced more axon regeneration and synapse reformation in the spinal cord caudal to the lesion site. Rostral to the lesion, the transected dCST axons sprouted into gray matter upon contact. Furthermore, forelimb function was found to be improved after combination therapy during behavioral testing. ConclusionCombining task-based rehabilitative training with PTEN inhibition further promotes axon regeneration, synaptic plasticity and reorganization of the neural network, with significant improvement in forelimb skilled motor function after cervical spinal cord injury. Our study provides new therapeutic insights for spinal cord injury management in the future.