Magnetic Field Boosts the Transmembrane Transport Efficiency of Magnesium Ions from PLLA Bone Scaffold.

In the system of magnesium-loaded scaffolds, the effect of magnesium ions (Mg2+ ) on the osteogenesis induction is restricted due to the low transmembrane transport efficiency of Mg2+ into the cell, which limits the application for bone defect repair. Inspired by the fact that magnetic field can regulate ion channel proteins on the cell membrane, magnetite nanoparticle is introduced into the poly (l-lactic acid) /magnesium oxide composite in this study, and a magnetic magnesium-loaded bone scaffold is prepared via selective laser sintering . Notably, the activities of the Mg2+ channel protein (MAGT1) on the membrane of bone marrow mesenchymal stem cells (rBMSCs) are enhanced via magnetic torque effect (via integrin αV ß3/actin), under the action of static magnetic field (SMF), which promoted rBMSCs to capture Mg2+ in the microenvironment and induced osteogenesis. In vitro experiments showed that the magnetic magnesium-loaded scaffold, under the action of SMF, can accelerate the inflow of Mg2+ from surrounding microenvironment, which improved cellular activities, osteogenesis-related gene expression (ALP, Runx2, OCN, and OPN), and mineralization. Besides, in vivo skull defect repair experiments showed that the scaffolds possessed good ability to promote bone differentiation and new bone regeneration.

Panax notoginseng Saponins Protect Brain Microvascular Endothelial Cells against Oxygen-Glucose Deprivation/Resupply-Induced Necroptosis via Suppression of RIP1-RIP3-MLKL Signaling Pathway.

Recently, necroptosis has emerged as one of the important mechanisms of ischemia stroke. Necroptosis can be rapidly activated in endothelial cells to cause vascular damage and neuroinflammation. Panax notoginseng saponins (PNS), an ingredient extracted from the root of Panax notoginseng (Burk.) F.H. Chen, was commonly used for ischemic stroke, while its molecular mechanism and targets have not been fully clarified. Our study aimed to clarify the anti-necroptosis effect of PNS by regulating RIP1-RIP3-MLKL signaling pathway in brain microvascular endothelial cells (BMECs) subjected to transient oxygen-glucose deprivation (OGD/resupply [R]). In vitro, the necroptosis model of rat BMECs was established by testing the effect of OGD/R in the presence of the pan-caspase inhibitor z-VAD-FMK. After administration of PNS and Nec-1, cell viability, cell death modality, the expression of RIP1-RIP3-MLKL pathway and mitochondrial membrane potential (Δψm) level were investigated in BMECs upon OGD/R injury. The results showed that PNS significantly enhanced cell viability of BMECs determined by CCK-8 analysis, and protected BMECs from necroptosis by Flow cytometry and TEM. In addition, PNS inhibited the phosphorylation of RIP1, RIP3, MLKL and the downstream expression of PGAM5 and Drp1, while similar results were observed in Nec-1 intervention. We further investigated whether PNS prevented the Δψm depolarization. Our current findings showed that PNS effectively reduced the occurrence of necroptosis in BMECs exposed to OGD/R by inhibition of the RIP1-RIP3-MLK signaling pathway and mitigation of mitochondrial damage. This study provided a novel insight of PNS application in clinics.

MBD2 mediates renal cell apoptosis via activation of Tox4 during rhabdomyolysis-induced acute kidney injury.

Our study investigated the role of Methyl-CpG-binding domain protein 2 (MBD2) in RM-induced acute kidney injury (AKI) both in vitro and in vivo. MBD2 was induced by myoglobin in BUMPT cells and by glycerol in mice. MBD2 inhibition via MBD2 small interfering RNA and MBD2-knockout (KO) attenuated RM-induced AKI and renal cell apoptosis. The expression of TOX high mobility group box family member 4 (Tox4) induced by myoglobin was markedly reduced in MBD2-KO mice. Chromatin immunoprecipitation analysis indicated that MBD2 directly bound to CpG islands in the Tox4 promoter region, thus preventing promoter methylation. Furthermore, siRNA inhibition of Tox4 attenuated myoglobin-induced apoptosis in BUMPT cells. Finally, MBD2-KO mice exhibited glycerol-induced renal cell apoptosis by inactivation of Tox4. Altogether, our results suggested that MBD2 plays a role in RM-induced AKI via the activation of Tox4 and represents a potential target for treatment of RM-associated AKI.

Mg2+ in ß-TCP/Mg-Zn composite enhances the differentiation of human bone marrow stromal cells into osteoblasts through MAPK-regulated Runx2/Osx.

Inducing the osteogenic differentiation from bone marrow stromal cells (BMSCs) might be a potent strategy for treating bone loss and nonunion during fracture and improving fracture healing. Among several signaling pathways involved, mitogen-activated protein kinases (MAPKs) have been reported to play a critical role. Magnesium (Mg)-based alloys, including Mg-Zn alloy, have been used clinically as implants in the musculoskeletal field and could promote BMSC osteogenic differentiation. However, the underlying mechanisms remain unclear. In this study, we produced Mg-Zn alloy consists of Mg and low concentrations of Zn, calcium carbonate, and ß-tricalcium phosphate (ß-TCP; manifesting process not shown), prepared Mg, Zn, and Mg-Zn extracts, and investigated the specific effects of these extracts on human BMSC (hBMSC) osteogenic differentiation and MAPK signaling. Mg extracts and Mg-Zn extracts could significantly promote the osteogenic differentiation of hBMSCs as manifested as increased alkaline phosphatase levels, enhanced calcium nodules formation, and increased messenger RNA expression and protein levels of osteogenesis markers, including BMPs, Col-I, Runx2, and Osx; in the meantime, Mg culture medium (CM) and Mg-Zn CM both significantly enhanced the activation of MAPK signaling in hBMSCs. By adding ERK1/2 signaling, p38 signaling, or JNK signaling inhibitor to Mg-Zn CM, or conducting p38 MAPK silence in hBMSCs, we revealed that these extracts might promote hBMSC osteogenic differentiation via p38 MAPK signaling and MAPK-regulated Runx2/Osx. In conclusion, Mg2+ in ß-TCP/Mg-Zn extract promotes the osteogenic differentiation of hBMSCs via MAPK-regulated Runx2/Osx interaction.

Bu zhong Yiqi Decoction ameliorates mild cognitive impairment by improving mitochondrial oxidative stress damage via the SIRT3/MnSOD/OGG1 pathway.

ETHNOPHARMACOLOGICAL RELEVANCE: Bu-Zhong-Yi-Qi Decoction(BZYQD) is a traditional formula commonly used in China, known for its effects in tonifying Qi and raising Yang. It can relieve symptoms of cognitive impairment such as forgetfulness and lack of concentration caused by qi deficiency, which is common in aging and debilitating. However, much of the current research on BZYQD has been focused on its impact on the digestive system, leaving its molecular mechanisms in improving cognitive function largely unexplored. AIM OF THE STUDY: Cognitive decline in the aging central nervous system is intrinsically linked to oxidative damage. This study aims to investigate the therapeutic mechanism of BZYQD in treating mild cognitive impairment caused by qi deficiency, particularly through repair of mitochondrial oxidative damage. MATERIALS AND METHODS: A rat model of mild cognitive impairment (MCI) was established by administering reserpine subcutaneously for two weeks, followed by a two-week treatment with BZYQD/GBE. In vitro experiments were conducted to assess the effects of BZYQD on neuronal cells using a H2O2-induced oxidative damage model in PC12 cells. The open field test and the Morris water maze test evaluated the cognitive and learning memory abilities of the rats. HE staining and TEM were employed to observe morphological changes in the hippocampus and its mitochondria. Mitochondrial activity, ATP levels, and cellular viability were measured using assay kits. Protein expression in the SIRT3/MnSOD/OGG1 pathway was analyzed in tissues and cells through western blotting. Levels of 8-OH-dG in mitochondria extracted from tissues and cells were quantified using ELISA. Mitochondrial morphology in PC12 cells was visualized using Mito Red, and mitochondrial membrane potential was assessed using the JC-1 kit. RESULTS: BZYQD treatment significantly improved cognitive decline caused by reserpine in rats, as well as enhanced mitochondrial morphology and function in the hippocampus. Our findings indicate that BZYQD mitigates mtDNA oxidative damage in rats by modulating the SIRT3/MnSOD/OGG1 pathway. In PC12 cells, BZYQD reduced oxidative damage to mitochondria and mtDNA in H2O2-induced conditions and was associated with changes in the SIRT3/MnSOD/OGG1 pathway. CONCLUSION: BZYQD effectively counteracts reserpine-induced mild cognitive impairment and ameliorates mitochondrial oxidative stress damage through the SIRT3/MnSOD/OGG1 pathway.

Leave for where? The impact of air quality on migration: Evidence at the city-pair level in China.

We comprehensively explore the question of "Leave for where?" by utilizing city-pair level data of China spanning from 2011 to 2017. Our investigation focuses on the impact of disparities in air quality between city pairs on migration. we find that a 1% increase in the difference air quality between inflow and outflow locations raises the number of people migrating from the outflow to the inflow location by approximately 0.07%. This finding is robust after overcoming possible endogeneity problems with average wind speed as an instrumental variable. In addition, we conducted a heterogeneity analysis in terms of intention to migrate and individual characteristics, finding that individuals who migrated for work and family are more sensitive to differences in air quality between city pairs, whereas those who moved for business are not sensitive to differences in air quality. Regarding individual characteristics, differences in air quality between city pairs have a greater impact on the migration decisions of low-educated, female, and younger migrants. Further, a mechanistic analysis by constructing cohort dummy variables reveals that poor air quality is more motivational than the desire for good air quality and the crowding-out effect of air pollution on migration is more pronounced.

EGFR mediated the renal cell apoptosis in rhabdomyolysis-induced model via upregulation of autophagy.

AIMS: Rhabdomyolysis is a life-threatening condition. One of the most common complications of rhabdomyolysis is acute kidney injury (AKI), and 10 % of all AKI patients present with rhabdomyolysis. EGFR is associated with different types of AKI. However, the function and regulatory mechanism of EGFR in rhabdomyolysis-induced AKI model remain unknown. Here, we performed the experiments to explore the role of EGFR in this model. MAIN METHODS: We used proximal tubule-specific Atg7 knockout mice and Wa-2 mice to establish animal models. Then, the samples were collected for pathology assay and IB detection. In vitro, the BUMPT cells treated with myoglobin were collected for the detection of apoptosis and autophagy. IB detection were processed for the analysis of protein expressions, FCM analysis for the cell apoptosis, GFP-LC3 transfection and immunofluorescent for autophagy. KEY FINDINGS: EGFR promotes autophagy to mediate rhabdomyolysis-induced AKI via STAT3/Atg7 axis, and gefitinib is a potential therapeutic option for AKI. Here, we demonstrated that EGFR was activated by myoglobin and glycerol both in vitro and in vivo, respectively. Genetic or pharmacological inhibition of EGFR ameliorated myoglobin and glycerol-induced renal cell apoptosis. Mechanistically, EGFR mediated autophagy induction via STAT3/Atg7 axis, thereby resulting in kidney cell apoptosis. Furthermore, Wa-2 mice or gefitinib treatment prevented the progression of rhabdomyolysis-induced AKI as well as renal cell apoptosis and autophagy via inhibiting STAT3/Atg7 axis. SIGNIFICANCE: Researchers can use this finding to better study the function and regulatory mechanism of EGFR in RM-induced AKI model. And gefitinib represents a potential target for treatment of AKI.

Proximal tubular RAGE mediated the renal fibrosis in UUO model mice via upregulation of autophagy.

Previous studies reported that RAGE participated in the process of kidney fibrosis, but the function and regulation pathway of RAGE in proximal tubular cells in this process remains unclear. Here, we found that expression of RAGE was increased by TGF-ß1 treatment and unilateral ureteral obstruction (UUO). Knock down of RAGE ameliorated renal fibrosis by TGF-ß1 treatment, the expression of vimentin, Collagen I&III, and fibronectin are decreased. Mechanistically, RAGE mediated TGF-ß1-induced phosphorylation of Stat3 and directly upregulated the Atg7 to increase the level of autophagy, and ultimately resulting in renal fibrosis. Furthermore, PT-RAGE-KO mice reduced kidney fibrosis in UUO model via inhibiting Stat3/Atg7 axis by knocking down RAGE. Furthermore, the above findings were confirmed in kidney of patients with obstructive nephropathy. Collectively, RAGE in proximal tubular cells promotes the autophagy to increase renal fibrosis via upregulation of Stat3/Atg7 axis.

LncRNA expression profile analysis of Mg2+-induced osteogenesis by RNA-seq and bioinformatics.

BACKGROUND: In recent years, magnesium (Mg) has been extensively studied for manufacturing biodegradable orthopedic devices. Besides other advantages, researches have shown that magnesium-based implants can stimulate osteogenesis thus accelerating orthopedic trauma recovery, but its molecular mechanism is not fully understood. Meanwhile, long non-coding RNA (lncRNA) has been found to play vital role in regulating osteogenic differentiation. OBJECTIVE: To explore the role of lncRNA in Mg2+ (magnesium ions)-induced osteogenesis. METHODS: The effect of Mg2+ on mBMSCs proliferation was detected by the CCK-8 assay. The optimum concentration of Mg2+ (7.5 mM) in promoting mBMSCs osteogenesis was determined by ALP staining and Alizarin red staining, western blot and RT-qPCR were performed to detect osteogenic markers expressions. The lncRNAs and mRNAs expression profiles of mBMSCs were assessed by RNA-Seq and processed by bioinformatics analysis. The selected lncRNAs expression level was validated by RT-qPCR. RESULTS: The effect of Mg2+ in promoting osteogenesis was confirmed and the optimum concentration was determined as 7.5 mM. The lncRNAs and mRNAs differentially expressed between 7.5 mM Mg2+-treated group and control group was detected and functional analysis revealed that their function were associated with osteogenesis. The ceRNA networks were constructed for H19 and Dubr that aberrantly expressed in two groups. The ceRNA networks of selected lncRNAs (H19 and Dubr) were constructed. CONCLUSIONS: This study identified H19 and Dubr as osteogenic associated lncRNAs involved in Mg2+-induced osteogenesis, and they might play their roles through lncRNA-miRNA-mRNA axis.

The RIG-I Signal Pathway Mediated Panax notoginseng Saponin Anti-Inflammatory Effect in Ischemia Stroke.

Panax notoginseng saponins (PNS), the main bioactive constituents of a traditional Chinese herb Panax notoginseng, were commonly used for ischemic stroke in China. However, the associated cellular and molecular mechanisms of PNS have not been well examined. This study aimed to decipher the underlying molecular target of PNS in the treatment of cerebral ischemia. The oxygen-glucose-deprived (OGD) model of rat brain microvascular endothelial cells (BMECs) was used in this study. The alteration of gene expression in rat BMECs after PNS treatment was measured by microarray and indicated that there were 38 signaling pathways regulated by PNS. Among them, RIG-I receptor and related signaling molecules TNF receptor-associated factor 2 (Traf2) and nuclear factor-kappa B (NF-κB) were significantly suppressed by PNS, which was verified again in OGD-induced BMECs measured by FQ-PCR and western blotting and in middle cerebral artery occlusion (MCAO) rats measured by immunohistochemistry. The levels of TNF-α, IL-8, and the downstream cytokines regulated by RIG-I receptor pathway were also decreased by PNS. Meanwhile, the neurological evaluation, hematoxylin and eosin (HE) staining, and Evans blue staining were conducted to evaluate the effect of PNS in MCAO rats. Results showed PNS significantly improved functional outcome and cerebral vascular leakage. Flow cytometry showed the number of the inflammatory cells infiltrated in brain tissue was decreased in PNS treatment. Our results identified that RIG-I signaling pathway mediated anti-inflammatory properties of PNS in cerebral ischemia, which provided the novel insights of PNS application in clinics.

miR-485-5p/HSP90 axis blocks Akt1 phosphorylation to suppress osteosarcoma cell proliferation and migration via PI3K/AKT pathway.

Osteosarcoma (OS) is closely related to the dysregulation of various intracellular signaling pathways, especially the PI3K/Akt signaling pathway. Reportedly, HSP90 was responsible for phospho-Akt stabilization, and both AKT1 and HSP90 were upregulated within osteosarcoma. Herein, we demonstrated that AKT1 and HSP90 mRNA and protein expression were upregulated within osteosarcoma tissues and cells; AKT1 knockdown significantly inhibited OS cell viability. HSP90 knockdown suppressed the phosphorylation of AKT1, decreased ki-67 and Vimentin protein levels, enhanced p21 and E-cadherin protein levels, and inhibited OS cell proliferation and migration; AKT1 overexpression exerted opposing effects and significantly attenuated the effects of HSP90 knockdown. miR-485-5p targeted AKT1 and HSP90 3'-UTR to inhibit AKT1 and HSP90 expression. miR-485-5p overexpression dramatically reduced AKT1, HSP90, and ki-67 proteins, increased E-cadherin protein levels, and inhibited OS cell proliferation and migration. In conclusion, HSP90 knockdown blocked the phosphorylation of AKT1 suppressing the proliferation and migration capacity of OS cells via the PI3K/AKT pathway; miR-485-5p binds to HSP90 and AKT1 in their 3'-UTR to inhibit HSP90 and AKT1 expression, therefore exerting a tumor suppressor function within osteosarcoma.

miR-342-5p inhibits osteosarcoma cell growth, migration, invasion, and sensitivity to Doxorubicin through targeting Wnt7b.

Osteosarcoma (OS) accounts for 9 percent of cancer-related deaths in young people. The PI3K/Akt signaling, a well-known carcinogenic signaling pathway in human cancer, cooperates with other signaling pathways such as Wnt signaling to promote cancer progression. Wnt7b, as a transforming member of the Wnt family, could activate mTORC1 through PI3K-AKT signaling and is upregulated in OS. In the present study, we found that miR-342-5p inhibits Wnt7b expression via direct binding to Wnt7b 3'-UTR. miR-342-5p overexpression remarkably suppressed the viability and invasion while enhanced the apoptosis of OS cells; meanwhile, Wnt7b, ß-catenin, c-myc, and cyclin D1 proteins were reduced while E-cadherin protein showed to be increased. Consistent with its expression pattern, Wnt7b exerted oncogenic effects on OS cells. Wnt7b could significantly attenuate the impacts of miR-342-5p. In conclusion, we demonstrated a miR-342-5p/Wnt7b axis that regulates the capacity of OS cells to proliferate and to invade through Wnt/ß-catenin signaling. The miR-342-5p/Wnt7b axis might be novel targets for OS targeted therapy, which needs further in vivo and clinical investigations.