RBM3 promotes neurogenesis in a niche-dependent manner via IMP2-IGF2 signaling pathway after hypoxic-ischemic brain injury

An active peptide from yak inhibits hypoxia-induced lung injury via suppressing VEGF/MAPK/inflammatory signaling

Pulmonary vascular remodeling and inflammation play an important role in the hypoxic-induced lung diseases. Our previous investigations showed that peptide from yak milk residues could alleviate inflammation. In this study, our results suggest that peptide (LV) from yak milk residues peptide had protective effect of lung in the animal models of hypoxic-induced lung injury. LV Gavage could improve pulmonary vascular remodeling in the lung tissues of hypoxic mice. A comprehensive analysis of metabolomics and transcriptomics revealed that 5-KETE, 8,9-EET, and 6-keto-prostaglandin F1a might be potential targets to prevent lung injury in the hypoxic mice. These metabolites can be regulated by MAPK/VEGF and inflammatory pathways. Our data indicated that LV treatment could inhibit apoptosis and inflammation via Nrf2/NF-κB/MAPK/PHD-2 pathway and protected hypoxic-induced lung epithelial cells injury. Taken together, our results suggest that LV provides a novel therapeutic clue for the prevention of hypoxia-induced lung injury and inflammation-related lung diseases.

RBM3 Ameliorates Acute Brain Injury-induced Inflammation and Oxidative Stress by Stabilizing GAS6 mRNA Through Nrf2 Signaling Pathway

RNA-binding motif protein 3 (RBM3), as a cold-inducible protein, exhibits neuroprotective function in brain disorders. This study was conducted to investigate the effects of RBM3 on acute brain injury (ABI) and its underlying mechanism. The cerebral injury (CI) rat model and oxygen-glucose deprivation (OGD) cell model were established. The neurological severity score, wire-grip score, morris water maze test, and Y-maze test were used to detect the neurological damage, vestibular motor, learning, and memory functions. Cerebral injury, apoptosis, oxidative stress, and inflammatory level were evaluated by hematoxylin-eosin and TUNEL staining and specific kits. Flow cytometry was used to analyze the apoptosis rate. The relationship between RBM3 and growth arrest specific (GAS) 6 was analyzed by RNA immunoprecipitation assay. The results indicated that RBM3 recovered of neurological function and behaviour impairment of CI rats. Additionally, RBM3 reversed the increased oxidative stress, inflammatory level, and apoptosis induced by CI and OGD. RBM3 interacted with GAS6 to activate the Nrf2 signaling pathway, thus playing neuroprotection on ABI. Besides, the results of RBM3 treatment were similar to those of mild hypothermia treatment. In summary, RBM3 exerted neuroprotection and ameliorated inflammatory levels and oxidative stress by stabilizing GAS6 mRNA through the Nrf2 signaling pathway, suggesting that RBM3 might be a potential therapeutic candidate for treating ABI.

Cold-shock proteome of myoblasts reveals role of RBM3 in promotion of mitochondrial metabolism and myoblast differentiation

Adaptation to hypothermia is important for skeletal muscle cells under physiological stress and is used for therapeutic hypothermia (mild hypothermia at 32  °C). We show that hypothermic preconditioning at 32  °C for 72 hours improves the differentiation of skeletal muscle myoblasts using both C2C12 and primary myoblasts isolated from 3 month and 18-month-old mice. We analyzed the cold-shock proteome of myoblasts exposed to hypothermia (32  °C for 6 and 48 h) and identified significant changes in pathways related to RNA processing and central carbon, fatty acid, and redox metabolism. The analysis revealed that levels of the cold-shock protein RBM3, an RNA-binding protein, increases with both acute and chronic exposure to hypothermic stress, and is necessary for the enhanced differentiation and maintenance of mitochondrial metabolism. We also show that overexpression of RBM3 at 37  °C is sufficient to promote mitochondrial metabolism, cellular proliferation, and differentiation of C2C12 and primary myoblasts. Proteomic analysis of C2C12 myoblasts overexpressing RBM3 show significant enrichment of pathways involved in fatty acid metabolism, RNA metabolism and the electron transport chain. Overall, we show that the cold-shock protein RBM3 is a critical factor that can be used for controlling the metabolic network of myoblasts.

Mild hypothermia promotes neuronal differentiation of human neural stem cells via RBM3-SOX11 signaling pathway

Both therapeutic hypothermia and neural stem cells (NSCs) transplantation have shown promise in neuroprotection and neural repair after brain injury. However, the effects of therapeutic hypothermia on neuronal differentiation of NSCs are not elucidated. In this study, we aimed to investigate whether mild hypothermia promoted neuronal differentiation in cultured and transplanted human NSCs (hNSCs). A significant increase in neuronal differentiation rate of hNSCs was found when exposed to 35°C, from 33% to 45% in vitro and from 7% to 15% in vivo. Additionally, single-cell RNA sequencing identified upregulation of RNA-binding motif protein 3 (RBM3) in neuroblast at 35°C, which stabilized the SRY-box transcription factor 11 (SOX11) mRNA and increased its protein expression, leading to an increase in neuronal differentiation of hNSCs. In conclusion, our study highlights that mild hypothermia at 35°C enhances hNSCs-induced neurogenesis through the novel RBM3-SOX11 signaling pathway, and provides a potential treatment strategy in brain disorders.

RBM3 Promotes Anti-inflammatory Responses in Microglia and Serves as a Neuroprotective Target of Ischemic Stroke

Ischemic stroke is a major cause of death and disability in adults. Hypothermic treatment is successful in treating neonatal cerebral ischemia, but its application is restricted in adult patients due to complex management strategies and severe adverse effects. Two homologous RNA-binding proteins, RBM3 and CIRP, are the only known cold-inducible proteins in vertebrates, and their expression levels are robustly elevated by mild to moderate hypothermia. In previous studies, we and others have demonstrated that both RBM3 and CIRP mediate the neuroprotective and neurogenic effects of hypothermia in cell and animal models. However, CIRP can also be detrimental to neurons by triggering neuroinflammatory responses, complicating its post-stroke functions. In this study, we compared the properties of the two cold-inducible RNA-binding proteins after ischemic stroke. Our results indicated that RBM3 expression was stimulated in the ischemic brain of stroke patients, while CIRP expression was not. In an experimental model, RBM3 can ameliorate ischemic-like insult by promoting neuronal survival and eliciting anti-inflammatory responses in activated microglia, while the impact of CIRP was intriguing. Collectively, our data supported the notion that RBM3 may be a more promising therapeutic target than CIRP for treating ischemic stroke. We further demonstrated that zr17-2, a small molecule initially identified to target CIRP, can specifically target RBM3 but not CIRP in microglia. zr17-2 demonstrated anti-inflammatory and neuroprotective effects after ischemic stroke both in vitro and in vivo, suggesting its potential therapeutic value.

Deubiquitinase Mysm1 regulates neural stem cell proliferation and differentiation by controlling Id4 expression

Neural stem cells (NSCs) are critical for brain development and maintenance of neurogenesis. However, the molecular mechanisms that regulate NSC proliferation and differentiation remain unclear. Mysm1 is a deubiquitinase and is essential for the self-renewal and differentiation of several stem cells. It is unknown whether Mysm1 plays an important role in NSCs. Here, we found that Mysm1 was expressed in NSCs and its expression was increased with age in mice. Mice with Mysm1 knockdown by crossing Mysm1 floxed mice with Nestin-Cre mice exhibited abnormal brain development with microcephaly. Mysm1 deletion promoted NSC proliferation and apoptosis, resulting in depletion of the stem cell pool. In addition, Mysm1-deficient NSCs skewed toward neurogenesis instead of astrogliogenesis. Mechanistic investigations with RNA sequencing and genome-wide CUT&Tag analysis revealed that Mysm1 epigenetically regulated Id4 transcription by regulating histone modification at the promoter region. After rescuing the expression of Id4, the hyperproliferation and imbalance differentiation of Mysm1-deficient NSCs was reversed. Additionally, knockdown Mysm1 in aged mice could promote NSC proliferation. Collectively, the present study identified a new factor Mysm1 which is essential for NSC homeostasis and Mysm1-Id4 axis may be an ideal target for proper NSC proliferation and differentiation.

New molecular mechanisms to explain the neuroprotective effects of insulin-like growth factor II in a cellular model of Parkinson's disease

INTRODUCTION

One of the hallmarks of Parkinsońs Disease (PD) is oxidative distress, leading to mitochondrial dysfunction and neurodegeneration. Insulin-like growth factor II (IGF-II) has been proven to have antioxidant and neuroprotective effects in some neurodegenerative diseases, including PD. Consequently, there isgrowing interest in understanding the different mechanisms involved in the neuroprotective effect of this hormone.

OBJECTIVES

To clarify the mechanism of action of IGF-II involved in the protective effect of this hormone.

METHODS

The present study was carried out on a cellular model PD based on the incubation of dopaminergic cells (SN4741) in a culture with the toxic 1-methyl-4-phenylpyridinium (MPP+), in the presence of IGF-II. This model undertakes proteomic analyses in order to understand which molecular cell pathways might be involved in the neuroprotective effect of IGF-II. The most important proteins found in the proteomic study were tested by Western blot, colorimetric enzymatic activity assay and immunocytochemistry. Along with the proteomic study, mitochondrial morphology and function were also studied by transmission electron microscopy and oxygen consumption rate. The cell cycle was also analysed using 7AAd/BrdU staining, and flow cytometry.

RESULTS

The results obtained indicate that MPP+, MPP++IGF-II treatment and IGF-II, when compared to control, modified the expression of 197, 246 proteins and 207 respectively. Some of these proteins were found to be involved in mitochondrial structure and function, and cell cycle regulation. Including IGF-II in the incubation medium prevents the cell damage induced by MPP+, recovering mitochondrial function and cell cycle dysregulation, and thereby decreasing apoptosis.

CONCLUSION

IGF-II improves mitochondrial dynamics by promoting the association of Mitofilin with mitochondria, regaining function and redox homeostasis. It also rebalances the cell cycle, reducing the amount of apoptosis and cell death by the regulation of transcription factors, such as Checkpoint kinase 1.

Vasculature cells control neuroglial co-localization and synaptic connection in a central nervous system tissue mimic system

Despite the development of neural tissue differentiation methods using a wide variety of stem cells and compartments, there is no standardized strategy for establishing synapses. As the neuronal network is developed in parallel with blood vessel angiogenesis in the central nervous system (CNS) from the embryonic period, we examined neuron-astrocyte-vasculature interactions to understand the effect of the vasculature on the development and stabilization of neurological morphogenesis. We generated a cellular co-culture module targeting the CNS that was embedded in a collagen-based extracellular matrix (ECM) gel. Our neuron-astrocyte-vascular complex module identified the neurological co-localization effect by endothelial cells, as well as the pericyte-induced improvement of synaptic connections. Furthermore, it was suggested that the PDGF, BDNF, IGF, and WNT/BMP pathways were upregulated in synaptic connections enhanced conditions, which are composed of neurexin. These results suggest that the integrity of the vasculature cells in the CNS is important for the establishment of neuronal networks and for synapse connection.

Unravelling of molecular biomarkers in synaptic plasticity of Alzheimer's disease: Critical role of the restoration of neuronal circuits

Learning and memory storage are the fundamental activities of the brain. Aberrant expression of synaptic molecular markers has been linked to memory impairment in AD. Aging is one of the risk factors linked to gradual memory loss. It is estimated that approximately 13 million people worldwide will have AD by 2050. A massive amount of oxidative stress is kept under control by a complex network of antioxidants, which occasionally fails and results in neuronal oxidative stress. Increasing evidence suggests that ROS may affect many pathological aspects of AD, including Aβ accumulation, tau hyperphosphorylation, synaptic plasticity, and mitochondrial dysfunction, which may collectively result in neurodegeneration in the brain. Further investigation into the relationship between oxidative stress and AD may provide an avenue for effective preservation and pharmacological treatment of this neurodegenerative disease. In this review, we briefly summarize the cellular mechanism underlying Aβ induced synaptic dysfunction. Since oxidative stress is common in the elderly and may contribute to the pathogenesis of AD, we also shed light on the role of antioxidant and inflammatory pathways in oxidative stress adaptation, which has a potential therapeutic target in neurodegenerative diseases.

Association Between Polymorphism in Diabetes Susceptibility Gene Insulin-Like Growth Factor 2mRNA-Binding Protein 2 and Risk of Diffuse Large B-Cell Lymphoma

Background

Numerous studies have shown that polymorphisms in the diabetes susceptibility gene, insulin-like growth factor 2mRNA-binding protein 2 (IGF2BP2), are associated with the occurrence and development of various malignant tumors; however, their correlation with the onset of diffuse large B-cell lymphoma (DLBCL) is still unknown. Therefore, this study aimed to explore whether IGF2BP2 polymorphisms increase the risk of developing DLBCL.

Methods

This study included 295 DLBCL patients and 331 healthy individuals. Peripheral blood was collected, and polymerase chain reaction-ligase detection reaction (PCR-LDR) was used to detect IGF2BP2 gene polymorphisms. Logistic regression was used to assess the association between IGF2BP2 polymorphism and the risk of DLBCL, adjusted for age, sex, and body mass index (BMI). P < .05 indicated statistical significance.

Results

The rs4402960 polymorphism in the IGF2BP2 gene was associated with the occurrence and development of DLBCL. After adjusting for age, sex, and BMI, GT (odd ratio [OR] = 1.54; 95% confidence interval [CI] = 1.08-2.19; P = .016), TT (OR = 2.00; 95% CI = 1.09-3.68; P = .026), and T genotype carrying (GT + TT) (OR = 1.62; 95% CI = 1.17-2.25; P = .004) significantly increased the risk of DLBCL. This study also found that the polymorphism rs1470579 was related to the development of DLBCL. After adjusting for age, sex, and BMI, AC (OR = 1.55; 95% CI = 1.11-2.17; P = .010), CC (OR = 2.18; 95% CI = 1.17-4.06; P = .014), and C genotype carrying (AC + CC) (OR = 1.64; 95% CI = 1.19-2.26; P = .002) significantly increased the risk of DLBCL.

Conclusions

Our study found that polymorphism in the IGF2BP2 gene was associated with an increased risk of developing DLBCL.

FGF21 modulates hippocampal cold-shock proteins and CA2-subregion proteins in neonatal mice with hypoxia-ischemia

BACKGROUND

Fibroblast growth factor 21 (FGF21) is a neuroprotectant with cognitive enhancing effects but with poorly characterized mechanism(s) of action, particularly in females. Prior studies suggest that FGF21 may regulate cold-shock proteins (CSPs) and CA2-marker proteins in the hippocampus but empirical evidence is lacking.

METHODS

We assessed in normothermic postnatal day (PND) 10 female mice, if hypoxic-ischemic (HI) brain injury (25 min 8% O2/92% N2) altered endogenous levels of FGF21 in serum or in the hippocampus, or its receptor β-klotho. We also tested if systemic administration of FGF21 (1.5 mg/kg) modulated hippocampal CSPs or CA2 proteins. Finally, we measured if FGF21 therapy altered markers of acute hippocampal injury.

RESULTS

HI increased endogenous serum FGF21 (24 h), hippocampal tissue FGF21 (4d), and decreased hippocampal β-klotho levels (4d). Exogenous FGF21 therapy modulated hippocampal CSP levels, and dynamically altered hippocampal CA2 marker expression (24 h and 4d). Finally, FGF21 ameliorated neuronal damage markers at 24 h but did not affect GFAP (astrogliosis) or Iba1 (microgliosis) levels at 4d.

CONCLUSIONS

FGF21 therapy modulates CSP and CA2 protein levels in the injured hippocampus. These proteins serve different biological functions, but our findings suggest that FGF21 administration modulates them in a homeostatic manner after HI.

IMPACT

Hypoxic-ischemic (HI) injury in female post-natal day (PND) 10 mice decreases hippocampal RNA binding motif 3 (RBM3) levels in the normothermic newborn brain. HI injury in normothermic newborn female mice alters serum and hippocampal fibroblast growth factor 21 (FGF21) levels 24 h post-injury. HI injury in normothermic newborn female mice alters hippocampal levels of N-terminal EF-hand calcium binding protein 2 (NECAB2) in a time-dependent manner. Exogenous FGF21 therapy ameliorates the HI-mediated loss of hippocampal cold-induced RNA-binding protein (CIRBP). Exogenous FGF21 therapy modulates hippocampal levels of CA2-marker proteins after HI.

Study on the protective effect of RNA-binding motif protein 3 in mild hypothermia oxygen-glucose deprivation/reoxygenation cell model

Mild hypothermia is proven neuroprotective in clinical practice. While hypothermia leads to the decrease of global protein synthesis rate, it upregulates a small subset of protein including RNA-binding motif protein 3 (RBM3). In this study, we treated mouse neuroblastoma cells (N2a) with mild hypothermia before oxygen-glucose deprivation/reoxygenation (OGD/R) and discovered the decrease of apoptosis rate, down-regulation of apoptosis-associated protein and enhancement of cell viability. Overexpression of RBM3 via plasmid exerted similar effect while silencing RBM3 by siRNAs partially reversed the protective effect exerted by mild hypothermia pretreatment. The protein level of Reticulon 3(RTN3), a downstream gene of RBM3, also increased after mild hypothermia pretreatment. Silencing RTN3 weakened the protective effect of mild hypothermia pretreatment or RBM3 overexpression. Also, the protein level of autophagy gene LC3B increased after OGD/R or RBM3 overexpression while silencing RTN3 decreased this trend. Furthermore, immunofluorescence observed enhanced fluorescence signal of LC3B and RTN3 as well as a large number of overlaps after RBM3 overexpressing. In conclusion, RBM3 plays a cellular protective role by regulating apoptosis and viability via its downstream gene RTN3 in the hypothermia OGD/R cell model and autophagy may participate in it.

Hypothermia increases cold-inducible protein expression and improves cerebellar-dependent learning after hypoxia ischemia in the neonatal rat

BACKGROUND

Hypoxic ischemic encephalopathy remains a significant cause of developmental disability.1,2 The standard of care for term infants is hypothermia, which has multifactorial effects.3-5 Therapeutic hypothermia upregulates the cold-inducible protein RNA binding motif 3 (RBM3) that is highly expressed in developing and proliferative regions of the brain.6,7 The neuroprotective effects of RBM3 in adults are mediated by its ability to promote the translation of mRNAs such as reticulon 3 (RTN3).8 METHODS: Hypoxia ischemia or control procedure was conducted in Sprague Dawley rat pups on postnatal day 10 (PND10). Pups were immediately assigned to normothermia or hypothermia at the end of the hypoxia. In adulthood, cerebellum-dependent learning was tested using the conditioned eyeblink reflex. The volume of the cerebellum and the magnitude of cerebral injury were measured. A second study quantified RBM3 and RTN3 protein levels in the cerebellum and hippocampus collected during hypothermia.

RESULTS

Hypothermia reduced cerebral tissue loss and protected cerebellar volume. Hypothermia also improved learning of the conditioned eyeblink response. RBM3 and RTN3 protein expression were increased in the cerebellum and hippocampus of rat pups subjected to hypothermia on PND10.

CONCLUSIONS

Hypothermia was neuroprotective in male and female pups and reversed subtle changes in the cerebellum after hypoxic ischemic.

IMPACT

Hypoxic ischemic produced tissue loss and a learning deficit in the cerebellum. Hypothermia reversed both the tissue loss and learning deficit. Hypothermia increased cold-responsive protein expression in the cerebellum and hippocampus. Our results confirm cerebellar volume loss contralateral to the carotid artery ligation and injured cerebral hemisphere, suggesting crossed-cerebellar diaschisis in this model. Understanding the endogenous response to hypothermia might improve adjuvant interventions and expand the clinical utility of this intervention.

Crocetin Regulates Functions of Neural Stem Cells to Generate New Neurons for Cerebral Ischemia Recovery

Many neurons undergo apoptosis after ischemic stroke. In the brain, neurogenesis has the potential for neuronal replacement and can be activated by external conditions to repair the injury. Crocetin (CRO), naturally extracted from the plant saffron, acts as a neuroprotective agent for ischemic stroke. However, the underlying mechanism remains unknown. In this work, the effect of CRO on neural stem cell (NSC) behaviors and subventricular zone neurogenesis is investigated. Initially, NSCs are incubated with different concentrations of CRO to detect the cell proliferation and differentiation in vitro. Second, ischemic stroke induced rats are treated with CRO using nimodipine (NMDP) as a comparison. The behavioral functions, infarcted volume, and apoptotic Nissl bodies of rats are noticeably improved after CRO-treatment, comparable to those of NMDP. In addition, the increased regional cerebral blood flow and promoted neuronal differentiation are achieved by CRO-treatment. Brain tissue examination shows significantly increased neuronal regeneration in the focal ischemic injury area. Meanwhile, the length of neurites is prolonged, indicating that CRO could potentially promote neurite extension to enhance cell-cell communication. These findings demonstrate that CRO facilitated the neuronal differentiation of NSCs by activating subventricular zone neurogenesis in damaged cortex and striatum sites to repair ischemic stroke.

Senescent immune cells accumulation promotes brown adipose tissue dysfunction during aging

Brown adipose tissue (BAT)-mediated thermogenesis declines with age. However, the underlying mechanism remains unclear. Here we reveal that bone marrow-derived pro-inflammatory and senescent S100A8⁺ immune cells, mainly T cells and neutrophils, invade the BAT of male rats and mice during aging. These S100A8⁺ immune cells, coupled with adipocytes and sympathetic nerves, compromise axonal networks. Mechanistically, these senescent immune cells secrete abundant S100A8 to inhibit adipose RNA-binding motif protein 3 expression. This downregulation results in the dysregulation of axon guidance-related genes, leading to impaired sympathetic innervation and thermogenic function. Xenotransplantation experiments show that human S100A8⁺ immune cells infiltrate mice BAT and are sufficient to induce aging-like BAT dysfunction. Notably, treatment with S100A8 inhibitor paquinimod rejuvenates BAT axon networks and thermogenic function in aged male mice. Our study suggests that targeting the bone marrow-derived senescent immune cells presents an avenue to improve BAT aging and related metabolic disorders.

ASO targeting RBM3 temperature-controlled poison exon splicing prevents neurodegeneration in vivo

Neurodegenerative diseases are increasingly prevalent in the aging population, yet no disease-modifying treatments are currently available. Increasing the expression of the cold-shock protein RBM3 through therapeutic hypothermia is remarkably neuroprotective. However, systemic cooling poses a health risk, strongly limiting its clinical application. Selective upregulation of RBM3 at normothermia thus holds immense therapeutic potential. Here we identify a poison exon within the RBM3 gene that is solely responsible for its cold-induced expression. Genetic removal or antisense oligonucleotide (ASO)-mediated manipulation of this exon yields high RBM3 levels independent of cooling. Notably, a single administration of ASO to exclude the poison exon, using FDA-approved chemistry, results in long-lasting increased RBM3 expression in mouse brains. In prion-diseased mice, this treatment leads to remarkable neuroprotection, with prevention of neuronal loss and spongiosis despite high levels of disease-associated prion protein. Our promising results in mice support the possibility that RBM3-inducing ASOs might also deliver neuroprotection in humans in conditions ranging from acute brain injury to Alzheimer's disease.

RBM3 is associated with acute lung injury in septic mice and patients via the NF-κB/NLRP3 pathway

Sepsis refers to host response disorders caused by infection, leading to life-threatening organ dysfunction. RNA-binding motif protein 3 (RBM3) is an important cold-shock protein that is upregulated in response to mild hypothermia or hypoxia. In this study, we aimed to investigate whether RBM3 is involved in sepsis-associated acute lung injury (ALI). Intraperitoneal injection of LPS (10 mg/kg) was performed in wild type (WT) and RBM3 knockout (KO, RBM3^-/^-) mice to establish an in vivo sepsis model. An NLRP3 inflammasome inhibitor, MCC950 (50 mg/kg), was injected intraperitoneally 30 min before LPS treatment. Serum, lung tissues, and BALF were collected 24 h later for further analysis. In addition, we also collected serum from sepsis patients and healthy volunteers to detect their RBM3 expression. The results showed that the expression of RBM3 in the lung tissues of LPS-induced sepsis mice and the serum of patients with sepsis was significantly increased and positively correlated with disease severity. In addition, RBM3 knockout (KO) mice had a low survival rate, and RBM3 KO mice had more severe lung damage, inflammation, lung cell apoptosis, and oxidative stress than WT mice. LPS treatment significantly increased the levels of nucleotide binding and oligomerization domain-like receptor family 3 (NLRP3) inflammasomes and mononuclear cell nuclear factor-κB (NF-κB) in the lung tissues of RBM3 KO mice. However, these levels were only slightly elevated in WT mice. Interestingly, MCC950 improved LPS-induced acute lung injury in WT and RBM3 KO mice but inhibited the expression of NLRP3, caspase-1, and IL-1β. In conclusion, RBM3 was overexpressed in sepsis patients and LPS-induced mice. RBM3 gene deficiency aggravated sepsis-associated ALI through the NF-κB/NLRP3 pathway.

RBM3 interacts with Raptor to regulate autophagy and protect cardiomyocytes from ischemia-reperfusion-induced injury

Acute myocardial infarction (AMI) is a common disease with high morbidity and mortality worldwide. However, postinfarction pathogenesis remains unclear, and it is particularly important to identify new therapeutic targets. The RNA-binding motif protein RBM3 (also known as cold-inducible protein) is known to promote translation and is associated with tumor proliferation and neuroprotection. However, little is known about the biological effects of RBM3 on myocardial infarction. In the present study, we found that RBM3 expression was significantly upregulated in ischemia-reperfusion (I/R) condition and downregulation of RBM3 inhibited autophagy and promoted apoptosis in cardiomyocytes. We confirmed that RBM3 interacts with Raptor to regulate the autophagy pathway. Taken together, these findings illustrate the protective effects of RBM3 against I/R-induced myocardial apoptosis through the autophagy pathway.

11S Proteasome Activator REGγ Promotes Aortic Dissection by Inhibiting RBM3 (RNA Binding Motif Protein 3) Pathway

BACKGROUND

Aortic dissection (AD) is a life-threatening cardiovascular disorder with high mortality and lacking underlying mechanisms or effective treatments. REGγ, the 11S proteasome activator known to promote the degradation of cellular proteins in a ubiquitin- and ATP-independent manner, emerges as a new regulator in the cardiovascular system.

METHODS

Using β-aminopropionitrile (BAPN)-subjected REGγ knockout AD mice and Ang II (angiotensin II)-treated REGγ deficiency vascular smooth muscle cells (VSMCs) to explore the effect of REGγ in AD progression.

RESULTS

REGγ was upregulated in mouse aorta of β-aminopropionitrile-induced AD model in vivo and Ang II-treated VSMCs in vitro. REGγ deficiency ameliorated AD progression in β-aminopropionitrile-induced mice by protecting against the switch in VSMCs from contractile to synthetic phenotype through suppressing RBM3 (RNA-binding motif protein 3) decay. Mechanically, REGγ interacted with and degraded the RNA-binding protein RBM3 directly, leading to decreased mRNA stability, lowered expression and transcriptional activity of transcription factor SRF (serum response factor), subsequently reduced transcription of VSMCs-specific contractile genes, α-SMA (alpha-smooth muscle actin) and SM22α (smooth muscle 22 alpha), caused the switch in VSMCs from contractile to synthetic phenotype and associated AD progression. Ablation of endogenous SRF or RBM3, or overexpressing exogenous RBM3 in VSMCs significantly blocked or reestablished the REGγ-dependent action on VSMCs phenotypic switch of Ang II stimulation in vitro. Furthermore, exogenously introducing RBM3 improved the switch in VSMCs from contractile to synthetic phenotype and associated AD features caused by REGγ in vivo.

CONCLUSIONS

Our results demonstrated that REGγ promoted the switch in VSMCs from contractile to synthetic phenotype and AD progression by inhibiting RBM3-SRF pathway, indicated that modulating REGγ-proteasome activity may be a potential therapeutic approach for AD-associated cardiovascular dysfunction.

Transcriptome Profile in the Mouse Brain of Hepatic Encephalopathy and Alzheimer's Disease

Hepatic encephalopathy (HE) is a chronic metabolic disease accompanied by neuropathological and neuropsychiatric features, including memory deficits, psychomotor dysfunction, depression, and anxiety. Alzheimer's disease (AD), the most common neurodegenerative disease, is characterized by tau hyperphosphorylation, excessive amyloid beta (Aβ) accumulation, the formation of fibrillary tangles, hippocampus atrophy, and neuroinflammation. Recent studies have suggested a positive correlation between HE and AD. Some studies reported that an impaired cholesterol pathway, abnormal bile acid secretion, excessive ammonia level, impaired Aβ clearance, astrocytic dysfunction, and abnormal γ-aminobutyric acid GABAergic neuronal signaling in HE may also be involved in AD pathology. However, the mechanisms and related genes involved in AD-like pathology in the HE brain are unclear. Thus, we compared the cortical transcriptome profile between an HE mouse model, bile duct ligation (BDL), and an AD mouse model, the 5×FAD. Our study showed that the expression of many genes implicated in HE is associated with neuronal dysfunction in AD mice. We found changes in various protein-coding RNAs, implicated in synapses, neurogenesis, neuron projection, neuron differentiation, and neurite outgrowth, and non-coding RNAs possibly associated with neuropathology. Our data provide an important resource for further studies to elucidate AD-like pathophysiology in HE patients.

Cold shock protein RBM3 is upregulated in the autophagy-deficient brain

Neural autophagy plays an important role in regulating protein quality control, brain homeostasis, and body temperature. However, the mechanism that links a defect in autophagy to body temperature has not been elucidated. Here, we report that RNA binding motif protein 3 (RBM3) is a potential candidate that regulates body temperature. We found that the body temperatures of Nestin-Cre ; Atg7 ^f/f conditional KO (cKO) mice were lower than that of wild-type (WT) mice. Moreover, RBM3 was upregulated in the Nestin-Cre ; Atg7 ^f/f brain. These data suggest that RBM3 is an implicit target that maintains body temperature influenced by neural autophagy.

Ischemic Stroke Impacts the Gut Microbiome, Ileal Epithelial and Immune Homeostasis

Ischemic stroke critically impacts neurovascular homeostasis, potentially resulting in neurological disorders. However, the mechanisms through which stroke-induced inflammation modifies the molecular and metabolic circuits, particularly in ileal epithelial cells (iECs), currently remain elusive. Using multiomic approaches, we illustrated that stroke impaired the ileal microbiome and associated metabolites, leading to increased inflammatory signals and altered metabolites, potentially deteriorating the iEC homeostasis. Bulk transcriptomic and metabolomic profiling demonstrated that stroke enhanced fatty acid oxidation while reducing the tricarboxylic acid (TCA) cycle in iECs within the first day after stroke. Intriguingly, single-cell RNA sequencing analysis revealed that stroke dysregulated cell-type-specific gene responses within iECs and reduced frequencies of goblet and tuft cells. Additionally, stroke augmented interleukin-17A+ γδ T cells but decreased CD4+ T cells in the ileum. Collectively, our findings provide a comprehensive overview of stroke-induced intestinal dysbiosis and unveil responsive gene programming within iECs with implications for disease development.

Artesunate regulates the proliferation and differentiation of neural stem cells by activating the JAK‑2/STAT‑3 signaling pathway in ischemic stroke

Ischemic stroke is one of the most common causes of disability and death globally; therefore, the repair and reconstruction of the central nervous system (CNS) after stroke is very important. Neural stem/progenitor cells (NSPCs) may be the key to cell replacement therapy to treat CNS damage. It has previously been reported that artesunate (ART) is involved in the regulation of the biological functions of NSPCs; however, the mechanism of action of ART remains unclear. In the present study, different concentrations of ART were used to treat NSPCs following oxygen-glucose deprivation (OGD). Cell viability and apoptosis were analyzed using Cell Counting Kit-8 assay and flow cytometry, respectively, whereas immunofluorescence analysis was used to measure the expression levels of the differentiation-related molecule doublecortin (DCX) and proliferating cell nuclear antigen (PCNA). Western blotting was performed to analyze the expression levels of molecules related to the JAK-2/STAT-3 signaling pathway. The present results indicated that treatment with ART following OGD significantly promoted the viability of NSPCs, inhibited the apoptosis of NSPCs, and promoted the expression of PCNA and DCX. Moreover, ART significantly downregulated the protein expression levels of phosphorylated (p)-JAK-2 and p-STAT-3. Furthermore, activation of the JAK-2/STAT-3 signaling pathway and treatment with ART reversed the effects of ART on the proliferation, apoptosis and differentiation of NSPCs. In conclusion, the present data suggested that ART may promote the proliferation and differentiation of NSPCs, and reduce the apoptosis of NSPCs, by inhibiting the JAK-2/STAT-3 signaling pathway. ART may potentially be used for the treatment of ischemic stroke.

Neuroprotective Effect of miR-483-5p Against Cardiac Arrest-Induced Mitochondrial Dysfunction Mediated Through the TNFSF8/AMPK/JNK Signaling Pathway

Substantial morbidity and mortality are associated with postcardiac arrest brain injury (PCABI). MicroRNAs(miRNAs) are essential regulators of neuronal metabolism processes and have been shown to contribute to alleviated neurological injury after cardiac arrest. In this study, we identified miRNAs related to the prognosis of patients with neurological dysfunction after cardiopulmonary resuscitation based on data obtained from the Gene Expression Omnibus (GEO) database. Then, we explored the effects of miR-483-5p on mitochondrial biogenesis, mitochondrial-dependent apoptosis, and oxidative stress levels after ischemia‒reperfusion injury in vitro and in vivo. MiR-483-5p was downregulated in PC12 cells and hippocampal samples compared with that in normal group cells and hippocampi. Overexpression of miR-483-5p increased the viability of PC12 cells after ischemia‒reperfusion injury and reduced the proportion of dead cells. A western blot analysis showed that miR-483-5p increased the protein expression of PCG-1, NRF1, and TFAM and reduced the protein expression of Bax and cleaved caspase 3, inhibiting the release of cytochrome c from mitochondria and alleviating oxidative stress injury by inhibiting the production of ROS and reducing MDA activity. We confirmed that miR-483-5p targeted TNFSF8 to regulate the AMPK/JNK pathway, thereby playing a neuroprotective role after cardiopulmonary resuscitation. Hence, this study provides further insights into strategies for inhibiting neurological impairment after cardiopulmonary resuscitation and suggests a potential therapeutic target for PCABI.

RBM3 is an outstanding cold shock protein with multiple physiological functions beyond hypothermia

RNA-binding motif protein 3 (RBM3), an outstanding cold shock protein, is rapidly upregulated to ensure homeostasis and survival in a cold environment, which is an important physiological mechanism in response to cold stress. Meanwhile, RBM3 has multiple physiological functions and participates in the regulation of various cellular physiological processes, such as antiapoptosis, circadian rhythm, cell cycle, reproduction, and tumogenesis. The structure, conservation, and tissue distribution of RBM3 in human are demonstrated in this review. Herein, the multiple physiological functions of RBM3 were summarized based on recent research advances. Meanwhile, the cytoprotective mechanism of RBM3 during stress under various adverse conditions and its regulation of transcription were discussed. In addition, the neuroprotection of RBM3 and its oncogenic role and controversy in various cancers were investigated in our review.

Neurogenesis and Proliferation of Neural Stem/Progenitor Cells Conferred by Artesunate via FOXO3a/p27Kip1 Axis in Mouse Stroke Model

Promoting neurogenesis and proliferation of endogenous neural stem/progenitor cells (NSPCs) is considered a promising strategy for neurorehabilitation after stroke. Our previous study revealed that a moderate dose of artesunate (ART, 150 mg/kg) could enhance functional recovery in middle cerebral artery occlusion (MCAO) mice. This study aimed to investigate the effects of ART treatment on neurogenesis and proliferation of NSPCs using a rodent MCAO model. MRI results indicated that the ischemic brain volume of MCAO mice was reduced by ART treatment. The results of diffusion tensor imaging, electron microscopic, and immunofluorescence of Tuj-1 also revealed that ischemia-induced white matter lesion was alleviated by ART treatment. After ischemia/reperfusion, the proportion of Brdu + endogenous NSPCs in the ipsilateral subventricular zone and peri-infarct cortex was increased by ART treatment. Furthermore, the neuro-restorative effects of ART were abolished by the overexpression of FOXO3a. These findings suggested that ART could rescue ischemia/reperfusion damage and alleviate white matter injury, subsequently contributing to post-stroke functional recovery by promoting neurogenesis and proliferation of endogenous NSPCs via the FOXO3a/p27Kip1 pathway.

The protective effect of MiR-27a on the neonatal hypoxic-ischemic encephalopathy by targeting FOXO1 in rats

BACKGROUND

Neonatal hypoxic-ischemic encephalopathy (HIE), a kind of hypoxic-ischemic brain damage caused by perinatal asphyxia, is the most crucial cause of neonatal death and long-term neurological dysfunction in children. We aimed to investigate the protective effects of micro (mi)R-27a on HIE in neonatal rats.

METHODS

A rat model of neonatal HIE was constructed by modification of the Rice-Vannucci model. Real-time quantitative polymerase chain reaction (RT-qPCR) was used to test the expressions of miR-27a, FOXO1 messenger RNA (mRNA), interleukin-1β (IL-1β) mRNA, and tumor necrosis factor-α (TNF-α) mRNA, and western blot was applied to test the expression of FOXO1. In order to overexpress miR-27a, an intracerebroventricular injection (i.c.v) of miR-27a mimic was administered. We adopted 2,3,5-triphenytetrazolium chloride (TTC) staining and brain water content measurement to test the effects of miR-27a on the infarcted volume and edema in brain after HIE. Flow cytometry (FCM) analysis was applied to test the effects of miR-27a on the infiltrated peripheral immune cells in the rat brains after HIE.

RESULTS

We successfully established a rat model of neonatal HIE. It was revealed that the expressions of miR-27a decreased gradually after HIE, however, the expressions of FOXO1 mRNA increased. After injection of the miR-27a mimic, the expression of miR-27a in the rat HIE model brains was significantly upregulated, however, the expression of FOXO1 was robustly downregulated. Both TTC staining and brain water content showed that the infarcted volume and brain edema was markedly increased after HIE. Interestingly, the overexpression of miR-27a reduced the infarcted volume and edema induced by HIE. Additionally, RT-qPCR and FCM analysis showed that HIE lead to increases of IL-1β, TNF-α, and infiltrated immune cells. Overexpression of miR-27a could reduce the expressions of IL-1β mRNA and TNF-α mRNA, and the cell numbers of infiltrated peripheral macrophages and neutrophils in the brain.

CONCLUSIONS

MiR-27a plays protective roles by reducing infarct volume and brain edema, and inhibiting inflammatory factors and infiltrated peripheral immune cells by targeting FOXO1 in neonatal HIE rats.

Small molecules as modulators of regulated cell death against ischemia/reperfusion injury

Ischemia/reperfusion (IR) injury contributes to disability and mortality worldwide. Due to the complicated mechanisms and lack of proper therapeutic targets, few interventions are available that specifically target the pathogenesis of IR injury. Regulated cell death (RCD) of endothelial and parenchymal cells is recognized as the promising intervening target. Recent advances in IR injury suggest that small molecules exhibit beneficial effects on various RCD against IR injury, including apoptosis, necroptosis, autophagy, ferroptosis, pyroptosis, and parthanatos. Here, we describe the mechanisms behind these novel promising therapeutic targets and explain the machinery powering the small molecules. These small molecules exert protection by targeting endothelial or parenchymal cells to alleviate IR injury. Therapies of the ideal combination of small molecules targeting multiple cell types have shown potent synergetic therapeutic effects, laying the foundation for novel strategies to attenuate IR injury.

The role of insulin-like growth factor 2 mRNA binding proteins in female reproductive pathophysiology

Insulin-like growth factor 2 (IGF2) mRNA binding proteins (IMPs) family belongs to a highly conserved family of RNA-binding proteins (RBPs) and is responsible for regulating RNA processing including localization, translation and stability. Mammalian IMPs (IMP1-3) take part in development, metabolism and tumorigenesis, where they are believed to play a major role in cell growth, metabolism, migration and invasion. IMPs have been identified that are expressed in ovary, placenta and embryo. The up-to-date evidence suggest that IMPs are involved in folliculogenesis, oocyte maturation, embryogenesis, implantation, and placentation. The dysregulation of IMPs not only contributes to carcinogenesis but also disturbs the female reproduction, and may participate in the pathogenesis of reproductive diseases and obstetric syndromes, such as polycystic ovary syndrome (PCOS), pre-eclampsia (PE), gestational diabetes mellitus (GDM) and gynecological tumors. In this review, we summarize the role of IMPs in female reproductive pathophysiology, and hope to provide new insights into the identification of potential therapeutic targets.

Pre-clinical and clinical studies on the role of RBM3 in muscle-invasive bladder cancer: longitudinal expression, transcriptome-level effects and modulation of chemosensitivity

Background

The response to neoadjuvant cisplatin-based chemotherapy (NAC) in muscle-invasive bladder cancer (MIBC) is impaired in up to 50% of patients due to chemoresistance, with no predictive biomarkers in clinical use. The proto-oncogene RNA-binding motif protein 3 (RBM3) has emerged as a putative modulator of chemotherapy response in several solid tumours but has a hitherto unrecognized role in MIBC.

Methods

RBM3 protein expression level in tumour cells was assessed via immunohistochemistry in paired transurethral resection of the bladder (TURB) specimens, cystectomy specimens and lymph node metastases from a consecutive cohort of 145 patients, 65 of whom were treated with NAC. Kaplan-Meier and Cox regression analyses were applied to estimate the impact of RBM3 expression on time to recurrence (TTR), cancer-specific survival (CSS), and overall survival (OS) in strata according to NAC treatment. The effect of siRNA-mediated silencing of RBM3 on chemosensitivity was examined in RT4 and T24 human bladder carcinoma cells in vitro. Cellular functions of RBM3 were assessed using RNA-sequencing and gene ontology analysis, followed by investigation of cell cycle distribution using flow cytometry.

Results

RBM3 protein expression was significantly higher in TURB compared to cystectomy specimens but showed consistency between primary tumours and lymph node metastases. Patients with high-tumour specific RBM3 expression treated with NAC had a significantly reduced risk of recurrence and a prolonged CSS and OS compared to NAC-untreated patients. In high-grade T24 carcinoma cells, which expressed higher RBM3 mRNA levels compared to RT4 cells, RBM3 silencing conferred a decreased sensitivity to cisplatin and gemcitabine. Transcriptomic analysis revealed potential involvement of RBM3 in facilitating cell cycle progression, in particular G₁/S-phase transition, and initiation of DNA replication. Furthermore, siRBM3-transfected T24 cells displayed an accumulation of cells residing in the G₁-phase as well as altered levels of recognised regulators of G₁-phase progression, including Cyclin D1/CDK4 and CDK2.

Conclusions

The presented data highlight the potential value of RBM3 as a predictive biomarker of chemotherapy response in MIBC, which could, if prospectively validated, improve treatment stratification of patients with this aggressive disease.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-09168-7.

Drug delivery approaches for HuR-targeted therapy for lung cancer

Lung cancer (LC) is often diagnosed at an advanced stage and conventional treatments for disease management have limitations associated with them. Novel therapeutic targets are thus avidly sought for the effective management of LC. RNA binding proteins (RBPs) have been convincingly established as key players in tumorigenesis, and their dysregulation is linked to multiple cancers, including LC. In this context, we review the role of Human antigen R (HuR), an RBP that is overexpressed in LC, and further associated with various aspects of LC tumor growth and response to therapy. Herein, we describe the role of HuR in LC progression and outline the evidences supporting various pharmacologic and biologic approaches for inhibiting HuR expression and function. These approaches, including use of small molecule inhibitors, siRNAs and shRNAs, have demonstrated favorable results in reducing tumor cell growth, invasion and migration, angiogenesis and metastasis. Hence, HuR has significant potential as a key therapeutic target in LC. Use of siRNA-based approaches, however, have certain limitations that prevent their maximal exploitation as cancer therapies. To address this, in the conclusion of this review, we provide a list of nanomedicine-based HuR targeting approaches currently being employed for siRNA and shRNA delivery, and provide a rationale for the immense potential therapeutic benefits offered by nanocarrier-based HuR targeting and its promise for treating patients with LC.

The RNA binding protein IMP2 drives a stromal-Th17 cell circuit in autoimmune neuroinflammation

Stromal cells are emerging as key drivers of autoimmunity, partially because they produce inflammatory chemokines that orchestrate inflammation. Chemokine expression is regulated transcriptionally but also through posttranscriptional mechanisms, the specific drivers of which are still incompletely defined. CCL2 (MCP1) is a multifunctional chemokine that drives myeloid cell recruitment. During experimental autoimmune encephalomyelitis (EAE), an IL-17–driven model of multiple sclerosis, CCL2 produced by lymph node (LN) stromal cells was essential for immunopathology. Here, we showed that Ccl2 mRNA upregulation in human stromal fibroblasts in response to IL-17 required the RNA-binding protein IGF-2 mRNA-binding protein 2 (IGF2BP2, IMP2), which is expressed almost exclusively in nonhematopoietic cells. IMP2 binds directly to CCL2 mRNA, markedly extending its transcript half-life, and is thus required for efficient CCL2 secretion. Consistent with this, Imp2^−/− mice showed reduced CCL2 production in LNs during EAE, causing impairments in monocyte recruitment and Th17 cell polarization. Imp2^–/– mice were fully protected from CNS inflammation. Moreover, deletion of IMP2 after EAE onset was sufficient to mitigate disease severity. These data showed that posttranscriptional control of Ccl2 in stromal cells by IMP2 was required to permit IL-17–driven progression of EAE pathogenesis.

Cooling and Sterile Inflammation in an Oxygen-Glucose-Deprivation/Reperfusion Injury Model in BV-2 Microglia

Objective

Cold-inducible RNA-binding protein (CIRBP) has been shown to be involved not only in cooling-induced cellular protection but also as a mediator of sterile inflammation, a critical mechanism of the innate immune response in ischemia/reperfusion (I/R) injury. The role of microglia and its activation in cerebral I/R injury warrants further investigation as both detrimental and regenerative properties have been described. Therefore, we investigated the effects of cooling, specifically viability, activation, and release of damage associated molecular patterns (DAMPs) on oxygen glucose deprivation/reperfusion- (OGD/R-) induced injury in murine BV-2 microglial cells.

Methods

Murine BV-2 microglial cells were exposed to 2 to 6 h OGD (0.2% O₂ in glucose- and serum-free medium) followed by up to 19 h of reperfusion, simulated by restoration of oxygen (21% O₂) and nutrients. Cells were maintained at either normothermia (37°C) or cooled to 33.5°C, 1 h after experimental start. Cultured supernatants were harvested after exposure to OGD for analysis of DAMP secretions, including high-mobility group box 1 (HMGB1), heat shock protein 70 (HSP70), and CIRBP, and cytotoxicity was assessed by lactate dehydrogenase releases after exposure to OGD and reperfusion. Intracellular cold-shock proteins CIRBP and RNA-binding motif 3 (RBM3) as well as caspases 9, 8, and 3 were also analyzed via Western blot analysis. Furthermore, inducible nitric oxide synthase (iNOS), ionized calcium-binding adaptor molecule 1 (Iba1), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-1β (IL-1β), interleukin-1α (IL-1α), monocyte chemotactic protein 1 (MCP-1), transforming growth factor β (TGFβ), CIRBP, and RBM3 gene expressions were assessed via reverse transcription polymerase chain reaction, and TNF-α, IL-6, and IL-1β releases into the cultured supernatants were assessed via enzyme-linked immunosorbent assays (ELISA).

Results

Prolonged exposure to OGD resulted in increased BV-2 necrotic cell death, which was attenuated by cooling. Cooling also significantly induced cold-shock proteins CIRBP and RBM3 gene expressions, with CIRBP expression more rapidly regulated than RBM3 and translatable to significantly increased protein expression. DAMPs including HMGB-1, HSP70, and CIRBP could be detected in cultured supernatants after 6 h of OGD with CIRBP release being significantly attenuated by cooling. Exposure to OGD suppressed cytokine gene expressions of IL-1β, TNF-α, MCP-1, and TGFβ independently of temperature management, whereas cooling led to a significant increase in IL-1α gene expression after 6 h of OGD. In the reperfusion phase, TNF-α and MCP-1 gene expressions were increased, and cooling was associated with significantly lower TGFβ gene expression. Interestingly, cooled Normoxia groups had significant upregulations of microglial activation marker, Iba1, IL-1β, and TNF-α gene expressions.

Conclusion

BV-2 microglial cells undergo necrotic cell death resulting in DAMP release due to OGD/R-induced injury. Cooling conveyed neuroprotection in OGD/R-injury as observable in increased cell viability as well as induced gene expressions of cold shock proteins. As cooling alone resulted in both upregulation of microglial activation, expression of proinflammatory cytokines, and cold shock protein transcript and protein expression, temperature management might have ambiguous effects in sterile inflammation. However, cooling resulted in a significant decrease of extracellular CIRBP, which has recently been characterized as a novel DAMP and a potent initiator and mediator of inflammation.

N6-methyladenosine reader YTH N6-methyladenosine RNA binding protein 3 or insulin like growth factor 2 mRNA binding protein 2 knockdown protects human bronchial epithelial cells from hypoxia/reoxygenation injury by inactivating p38 MAPK, AKT, ERK1/2, and NF-κB pathways

Lung ischemia/reperfusion (I/R) injury (LIRI) is a common complication after lung transplantation, embolism, and trauma. N6-methyladenosine (m6A) methylation modification is implicated in the pathogenesis of I/R injury. However, there are no or few reports of m6A-related regulators in LIRI till now. In this text, dysregulated genes in lung tissues of LIRI rats versus the sham group were identified by RNA sequencing (RNA-seq). RNA-seq outcomes revealed that only YTH N6-methyladenosine RNA binding protein 3 (YTHDF3) and insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2) were differentially expressed in the LIRI versus sham group among 20 m6A-related regulators. Next, the functions and molecular mechanisms of YTHDF3 and IGF2BP2 in LIRI were investigated in a hypoxia/reoxygenation-induced BEAS-2B cell injury model in vitro. Results showed that YTHDF3 or IGF2BP2 knockdown attenuated hypoxia/reoxygenation-mediated inhibitory effects on cell survival and cell cycle progression and inhibited hypoxia/reoxygenation-induced cell apoptosis and pro-inflammatory cytokine secretion in BEAS-2B cells. Genes that could be directly regulated by YTHDF3 or IGF2BP2 were identified based on prior experimental data and bioinformatics analysis. Moreover, multiple potential downstream pathways of YTHDF3 and IGF2BP2 were identified by the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analysis of the above-mentioned genes. Among these potential pathways, we demonstrated that YTHDF3 or IGF2BP2 knockdown inhibited hypoxia/reoxygenation-activated p38, ERK1/2, AKT, and NF-κB pathways in BEAS-2B cells. In conclusion, YTHDF3 or IGF2BP2 knockdown weakened hypoxia/reoxygenation-induced human lung bronchial epithelial cell injury by inactivating p38, AKT, ERK1/2, and NF-κB pathways.

Secondary hypoxic ischemia alters neurobehavioral outcomes, neuroinflammation, and oxidative stress in mice exposed to controlled cortical impact

Objective

Hypoxic ischemia (HI) is a secondary insult that can cause fatal neurologic outcomes after traumatic brain injury (TBI), ranging from mild cognitive deficits to persistent vegetative states. We here aimed to unravel the underlying pathological mechanisms of HI injury in a TBI mouse model.

Methods

Neurobehavior, neuroinflammation, and oxidative stress were assessed in a mouse model of controlled cortical impact (CCI) injury followed by HI. Mice underwent CCI alone, CCI followed by HI, HI alone, or sham operation. HI was induced by one-vessel carotid ligation with 1 hour of 8% oxygen in nitrogen. Learning and memory were assessed using the novel object recognition test, contextual and cued fear conditioning, and Barnes maze test. Brain cytokine production and oxidative stress-related components were measured.

Results

Compared to TBI-only animals, TBI followed by HI mice exhibited significantly poorer survival and health scores, spatial learning and memory in the Barnes maze test, discrimination memory in the novel object recognition test, and fear memory following contextual and cued fear conditioning. Malondialdehyde levels were significantly lower, whereas glutathione peroxidase activity was significantly higher in TBI followed by HI mice compared to TBI-only and sham counterparts, respectively. Interleukin-6 levels were significantly higher in TBI followed by HI mice compared to both TBI-only and sham animals.

Conclusion

Post-traumatic HI aggravated deficits in spatial, fear, and discrimination memory in an experimental TBI mouse model. Our results suggest that increased neuroinflammation and oxidative stress contribute to HI-induced neurobehavioral impairments after TBI.

Cold-Induced RNA-Binding Protein Promotes Glucose Metabolism and Reduces Apoptosis by Increasing AKT Phosphorylation in Mouse Skeletal Muscle Under Acute Cold Exposure

The main danger of cold stress to animals in cold regions is systemic metabolic changes and protein synthesis inhibition. Cold-induced RNA-binding protein is a cold shock protein that is rapidly up-regulated under cold stimulation in contrast to the inhibition of most proteins and participates in multiple cellular physiological activities by regulating targets. Therefore, this study was carried out to investigate the possible mechanism of CIRP-mediated glucose metabolism regulation and survival promotion in skeletal muscle after acute cold exposure. Skeletal muscle and serum from mice were obtained after 0, 2, 4 and 8 h of acute hypothermia exposure. Subsequently, the changes of CIRP, metabolism and apoptosis were examined. Acute cold exposure increased energy consumption, enhanced glycolysis, increased apoptosis, and up-regulated CIRP and phosphorylation of AKT. In addition, CIRP overexpression in C2C12 mouse myoblasts at each time point under 37°C and 32°C mild hypothermia increased AKT phosphorylation, enhanced glucose metabolism, and reduced apoptosis. CIRP knockdown by siRNA interference significantly reduced the AKT phosphorylation of C2C12 cells. Wortmannin inhibited the AKT phosphorylation of skeletal muscle after acute cold exposure, thereby inhibiting glucose metabolism and aggravating apoptosis. Taken together, acute cold exposure up-regulates CIRP in mouse skeletal muscle, which regulates glucose metabolism and maintains energy balance in skeletal muscle cells through the AKT signaling pathway, thus slowing down the apoptosis of skeletal muscle cells.

Insulin-Like Growth Factor-II and Ischemic Stroke-A Prospective Observational Study

Insulin-like growth factor-II (IGF-II) regulates prenatal brain development, but the role in adult brain function and injury is unclear. Here, we determined whether serum levels of IGF-II (s-IGF-II) are associated with mortality and functional outcome after ischemic stroke (IS). The study population comprised ischemic stroke cases (n = 492) and controls (n = 514) from the Sahlgrenska Academy Study on Ischemic Stroke (SAHLSIS). Functional outcome was evaluated after 3 months and 2 years using the modified Rankin Scale (mRS), and additionally, survival was followed at a minimum of 7 years or until death. S-IGF-II levels were higher in IS cases both in the acute phase and at 3-month follow-up compared to controls (p < 0.05 and p < 0.01, respectively). The lowest quintile of acute s-IGF-II was, compared to the four higher quintiles, associated with an increased risk of post-stroke mortality (median follow-up 10.6 years, crude hazard ratio (HR) 2.34, 95% confidence interval (CI) 1.56–3.49, and fully adjusted HR 1.64, 95% CI 1.02–2.61). In contrast, crude associations with poor functional outcome (mRS 3–6) lost significance after full adjustment for covariates. In conclusion, s-IGF-II was higher in IS cases than in controls, and low acute s-IGF-II was an independent risk marker of increased mortality.

Unraveling the Big Sleep: Molecular Aspects of Stem Cell Dormancy and Hibernation

Tissue-resident stem cells may enter a dormant state, also known as quiescence, which allows them to withstand metabolic stress and unfavorable conditions. Similarly, hibernating mammals can also enter a state of dormancy used to evade hostile circumstances, such as food shortage and low ambient temperatures. In hibernation, the dormant state of the individual and its cells is commonly known as torpor, and is characterized by metabolic suppression in individual cells. Given that both conditions represent cell survival strategies, we here compare the molecular aspects of cellular quiescence, particularly of well-studied hematopoietic stem cells, and torpor at the cellular level. Critical processes of dormancy are reviewed, including the suppression of the cell cycle, changes in metabolic characteristics, and cellular mechanisms of dealing with damage. Key factors shared by hematopoietic stem cell quiescence and torpor include a reversible activation of factors inhibiting the cell cycle, a shift in metabolism from glucose to fatty acid oxidation, downregulation of mitochondrial activity, key changes in hypoxia-inducible factor one alpha (HIF-1α), mTOR, reversible protein phosphorylation and autophagy, and increased radiation resistance. This similarity is remarkable in view of the difference in cell populations, as stem cell quiescence regards proliferating cells, while torpor mainly involves terminally differentiated cells. A future perspective is provided how to advance our understanding of the crucial pathways that allow stem cells and hibernating animals to engage in their 'great slumbers.'

Alteration of mRNA 5-Methylcytosine Modification in Neurons After OGD/R and Potential Roles in Cell Stress Response and Apoptosis

Epigenetic modifications play an important role in central nervous system disorders. As a widespread posttranscriptional RNA modification, the role of the m5C modification in cerebral ischemia-reperfusion injury (IRI) remains poorly defined. Here, we successfully constructed a neuronal oxygen-glucose deprivation/reoxygenation (OGD/R) model and obtained an overview of the transcriptome-wide m5C profiles using RNA-BS-seq. We discovered that the distribution of neuronal m5C modifications was highly conserved, significantly enriched in CG-rich regions and concentrated in the mRNA translation initiation regions. After OGD/R, modification level of m5C increased, whereas the number of methylated mRNA genes decreased. The amount of overlap of m5C sites with the binding sites of most RNA-binding proteins increased significantly, except for that of the RBM3-binding protein. Moreover, hypermethylated genes in neurons were significantly enriched in pathological processes, and the hub hypermethylated genes RPL8 and RPS9 identified by the protein-protein interaction network were significantly related to cerebral injury. Furthermore, the upregulated transcripts with hypermethylated modification were enriched in the processes involved in response to stress and regulation of apoptosis, and these processes were not identified in hypomethylated transcripts. In final, we verified that OGD/R induced neuronal apoptosis in vitro using TUNEL and western blot assays. Our study identified novel m5C mRNAs associated with ischemia-reperfusion in neurons, providing valuable perspectives for future studies on the role of the RNA methylation in cerebral IRI.

Research Progress of the Application of Hypothermia in the Eye

Hypothermia is widely used in the medical field to protect organs or tissues from damage. Different research fields have different explanations of the protection mechanism of hypothermia. Hypothermia is also widely used in the field of ophthalmology, for example, in the eye bank, the preservation of corneal tissue and the preservation of the eyeball. Low temperature can also be applied to some ophthalmic diseases, such as allergic conjunctivitis, retinal ischemia, and retinal hypoxia. It is used to relieve eye symptoms or reduce tissue damage. Hypothermic techniques have important applications in ophthalmic surgery, such as corneal refractive surgery, vitrectomy surgery, and ciliary body cryotherapy for end-stage glaucoma. Hypothermia can reduce the inflammation of the cornea and protect the retinal tissue. The eyeball is a complex organ, including collagen tissue of the eyeball wall and retinal nerve tissue and retinal blood vessels. The mechanism of low temperature protecting eye tissue is complicated. It is important to understand the mechanism of hypothermia and its applications in ophthalmology. This review introduces the mechanism of hypothermia and its application in the eye banks, eye diseases (allergic conjunctivitis, retinal ischemia, and hypoxia), and eye surgeries (corneal transplant surgery, corneal refractive surgery, and vitrectomy).

The mRNA-Binding Protein RBM3 Regulates Activity Patterns and Local Synaptic Translation in Cultured Hippocampal Neurons

The activity and the metabolism of the brain change rhythmically during the day/night cycle. Such rhythmicity is also observed in cultured neurons from the suprachiasmatic nucleus, which is a critical center in rhythm maintenance. However, this issue has not been extensively studied in cultures from areas less involved in timekeeping, as the hippocampus. Using neurons cultured from the hippocampi of newborn rats (both male and female), we observed significant time-dependent changes in global activity, in synaptic vesicle dynamics, in synapse size, and in synaptic mRNA amounts. A transcriptome analysis of the neurons, performed at different times over 24 h, revealed significant changes only for RNA-binding motif 3 (Rbm3). RBM3 amounts changed, especially in synapses. RBM3 knockdown altered synaptic vesicle dynamics and changed the neuronal activity patterns. This procedure also altered local translation in synapses, albeit it left the global cellular translation unaffected. We conclude that hippocampal cultured neurons can exhibit strong changes in their activity levels over 24 h, in an RBM3-dependent fashion.

SIGNIFICANCE STATEMENT This work is important in several ways. First, the discovery of relatively regular activity patterns in hippocampal cultures implies that future studies using this common model will need to take the time parameter into account, to avoid misinterpretation. Second, our work links these changes in activity strongly to RBM3, in a fashion that is independent of the canonical clock mechanisms, which is a very surprising observation. Third, we describe here probably the first molecule (RBM3) whose manipulation affects translation specifically in synapses, and not at the whole-cell level. This is a key finding for the rapidly growing field of local synaptic translation.

Nuclear receptor TLX may be through regulating the SIRT1/NF-κB pathway to ameliorate cognitive impairment in chronic cerebral hypoperfusion

BACKGROUND

Chronic cerebral hypoperfusion (CCH) is a common pathophysiological mechanism in neurodegenerative diseases, such as Alzheimer's disease and vascular dementia. The orphan nuclear receptor TLX plays an important role in neural development, adult neurogenesis and cognition. The aim of this study was to investigate the neuroprotective effects of TLX on cognitive dysfunction, hippocampal neurogenesis and neuroinflammation in a rat model of CCH and to assess the possible mechanisms.

METHODS

Permanent bilateral common carotid artery occlusion (2-VO) was used to establish a model of CCH. Stereotaxic injection of an adeno-associated virus vector expressing TLX was used to overexpress TLX in the hippocampus. Cognitive function was evaluated by the Morris Water Maze test. Immunofluorescent staining was used to assess hippocampal neurogenesis. The effects of overexpression of TLX on SIRT1 and inflammatory cytokines were analyzed with qRT-PCR and western blot.

RESULT

After 2-VO, CCH rats exhibited cognitive impairment and reduction of hippocampal TLX levels. Overexpression of TLX ameliorated cognitive impairments with increasing number of BrdU + cells and BrdU + NeuN + cells in DG. Furthermore, TLX rescued the reduced SIRT1 usually induced by CCH. Additionally, TLX also inhibited the expression of inflammatory cytokines such as NF-κB and IL-1β.

CONCLUSIONS

The present findings suggested that TLX exerted protective effects against cognitive deficits induced by CCH. The possible mechanisms of TLX may be through regulating the SIRT1/NF-κB pathway, promoting hippocampal neurogenesis and inhibiting the neuroinflammatory response.

Data mining of human plasma proteins generates a multitude of highly predictive aging clocks that reflect different aspects of aging

We previously identified 529 proteins that had been reported by multiple different studies to change their expression level with age in human plasma. In the present study, we measured the q-value and age coefficient of these proteins in a plasma proteomic dataset derived from 4263 individuals. A bioinformatics enrichment analysis of proteins that significantly trend toward increased expression with age strongly implicated diverse inflammatory processes. A literature search revealed that at least 64 of these 529 proteins are capable of regulating life span in an animal model. Nine of these proteins (AKT2, GDF11, GDF15, GHR, NAMPT, PAPPA, PLAU, PTEN, and SHC1) significantly extend life span when manipulated in mice or fish. By performing machine-learning modeling in a plasma proteomic dataset derived from 3301 individuals, we discover an ultra-predictive aging clock comprised of 491 protein entries. The Pearson correlation for this clock was 0.98 in the learning set and 0.96 in the test set while the median absolute error was 1.84 years in the learning set and 2.44 years in the test set. Using this clock, we demonstrate that aerobic-exercised trained individuals have a younger predicted age than physically sedentary subjects. By testing clocks associated with 1565 different Reactome pathways, we also show that proteins associated with signal transduction or the immune system are especially capable of predicting human age. We additionally generate a multitude of age predictors that reflect different aspects of aging. For example, a clock comprised of proteins that regulate life span in animal models accurately predicts age.

RNA Binding Protein Motif 3 Inhibits Oxygen-Glucose Deprivation/Reoxygenation-Induced Apoptosis Through Promoting Stress Granules Formation in PC12 Cells and Rat Primary Cortical Neurons

As a sensitive cold-shock protein, RNA binding protein motif 3 (RBM3) exhibits a neuroprotective function in the condition of brain injury. However, how RBM3 is involved in acute ischemic stroke by affecting stress granules (SGs) remains unclear. Here, we established an oxygen-glucose deprivation/reperfusion (OGD/R) model in rat primary cortical neurons and PC12 cells to explore the potential mechanism between RBM3 and SG formation in acute ischemic/reperfusion (I/R) condition. The immunofluorescence results showed that the SG formation significantly decreased in rat primary cortical neurons and PC12 cells during the reperfusion period after 6 h of OGD stimulation. The western blot results, flow cytometry analysis, and cell viability assessment showed that the RBM3 expression and ratio of cell viability significantly decreased, while the rate of apoptosis increased in PC12 cells during the reperfusion period after 6 h of OGD stimulation. Co-immunoprecipitation (Co-IP) and immunofluorescence indicated that RBM3 and GTPase-activating protein-binding protein 1 (G3BP1) colocalized cytoplasm of PC12 cells after 6 h of OGD stimulation when the SGs formation reached the highest level. Besides, overexpression and knockdown of the RBM3 were achieved via plasmid transfection and CRISPR-Cas9 technology, respectively. The results of overexpression and knockdown of RBM3 gene illustrated the pivotal role of RBM3 in affecting SG formation and apoptosis level in OGD-treated PC12 cells. In conclusion, RBM3 could combine with G3BP1 resulted in increasing stress granules generation in rat primary cortical neurons and PC12 cells after 6 h of oxygen-glucose deprivation (OGD) injury, which ultimately reduced the apoptosis in OGD-induced cells. Our study may enable a new promising target for alleviating ischemia-reperfusion injury in cells.

Identification of RNA-Binding Proteins as Targetable Putative Oncogenes in Neuroblastoma

Neuroblastoma is a common childhood cancer with almost a third of those affected still dying, thus new therapeutic strategies need to be explored. Current experimental therapies focus mostly on inhibiting oncogenic transcription factor signalling. Although LIN28B, DICER and other RNA-binding proteins (RBPs) have reported roles in neuroblastoma development and patient outcome, the role of RBPs in neuroblastoma is relatively unstudied. In order to elucidate novel RBPs involved in MYCN-amplified and other high-risk neuroblastoma subtypes, we performed differential mRNA expression analysis of RBPs in a large primary tumour cohort (n = 498). Additionally, we found via Kaplan–Meier scanning analysis that 685 of the 1483 tested RBPs have prognostic value in neuroblastoma. For the top putative oncogenic candidates, we analysed their expression in neuroblastoma cell lines, as well as summarised their characteristics and existence of chemical inhibitors. Moreover, to help explain their association with neuroblastoma subtypes, we reviewed candidate RBPs’ potential as biomarkers, and their mechanistic roles in neuronal and cancer contexts. We found several highly significant RBPs including RPL22L1, RNASEH2A, PTRH2, MRPL11 and AFF2, which remain uncharacterised in neuroblastoma. Although not all RBPs appear suitable for drug design, or carry prognostic significance, we show that several RBPs have strong rationale for inhibition and mechanistic studies, representing an alternative, but nonetheless promising therapeutic strategy in neuroblastoma treatment.

Cold stress protein RBM3 responds to hypothermia and is associated with good stroke outcome

RNA-binding motif protein 3 is a molecular marker of hypothermia that has proved neuroprotective in neurodegenerative disease models. However, its relationship to the well-recognized therapeutic effect of hypothermia in ischaemic stroke had not been studied. In this work, the expression of RNA-binding motif protein 3 was investigated in ischaemic animal models subjected to systemic and focal brain hypothermia, specifically the effects of RNA-binding motif protein 3 silencing and overexpression on ischaemic lesions. Moreover, the association of RNA-binding motif protein 3 levels with body temperature and clinical outcome was evaluated in two independent cohorts of acute ischaemic stroke patients (n = 215); these levels were also determined in a third cohort of 31 patients derived from the phase III EuroHYP-1 trial of therapeutic cooling in ischaemic stroke. The preclinical data confirmed the increase of brain RNA-binding motif protein 3 levels in ischaemic animals subjected to systemic and focal hypothermia; this increase was selectively higher in the cooled hemisphere of animals undergoing focal brain hypothermia, thus confirming the direct effect of hypothermia on RNA-binding motif protein 3 expression, while RNA-binding motif protein 3 up-regulation in ischaemic brain regions led to functional recovery. Clinically, patients with body temperature <37.5°C in the first two cohorts had higher RNA-binding motif protein 3 values at 24 h and good outcome at 3 months post-ischaemic stroke, while RNA-binding motif protein 3 levels in the cooled third cohort tended to exceed those in placebo-treated patients. These results make RNA-binding motif protein 3 a molecular marker associated with the effect of hypothermia in ischaemic stroke and suggest its potential application as a promising protective target.

The RNA-Binding Protein RBM3 Promotes Neural Stem Cell (NSC) Proliferation Under Hypoxia

Neural stem cells (NSCs) reside physiologically in a hypoxic niche to maintain self-renewal and multipotency. Whereas mild hypoxia is known to promote NSC proliferation, severe hypoxia in pathological conditions exerts the reverse effect. The multi-functional RNA-binding protein RBM3 is abundant in NSCs and can be regulated by hypoxic exposure. Although RBM3 has been shown to accelerate cell growth in many cell types, whether and how it affects NSC proliferation in hypoxic environment remains largely unknown. In this study, we tested how RBM3 regulates cell proliferation under hypoxia in C17.2 mouse NSC cell line and in primary mouse NSCs from both the forebrain of postnatal day 0 (P0) mice and the subgranular zone (SGZ) of adult mice. Our results demonstrated that RBM3 expression was highly sensitive to hypoxia, and NSCs were arrested in G0/G1 phase by 5, 2.5, and 1% O₂ treatment. When we overexpressed RBM3, hypoxia-induced cell cycle arrest in G0/G1 phase was relieved and more cell transit into S phase was observed. Furthermore, cell viability under hypoxia was also increased by RBM3. In contrast, in RBM3-depleted primary NSCs, less BrdU-incorporated cells were detected, indicating exacerbated cell cycle arrest in G1 to S phase transition. Instead, overexpressed RBM3 significantly increased proliferation ratio in primary NSCs. Our findings indicate RBM3 as a potential target to maintain the proliferation capacity of NSCs under hypoxia, which can be important in NSC-based therapies of acute brain injury and chronic neurodegenerative diseases.