Effect of rotary motion on Fos protein expression in the vestibular-related nucleus population in a mouse model of rapid retinal degeneration

BACKGROUND： Previous studies on integration mechanisms of visual and vestibular information in the central nervous system have focused on the vestibular system. Due to the lack of an appropriate animal model, few studies have addressed the visual system with regard to visual and vestibular information. OBJECTIVE： To investigate Fos protein expression differences of vestibular-related nucleus populations in a mouse model of rapid retinal degeneration and normal wild-type Kunming mice following rotary motion, and to verify integration regions of visual and vestibular information in the central nervous system. DESIGN, TIME AND SETTING： A randomized, controlled in vitro study was performed at the Key Laboratory of Aerospace Medicine of Ministry of Education, China from March 2008 to February 2009. MATERIALS： A rotary stimulation device was re-fit to an electric, rotating chair produced by the School of Aerospace Medicine, the Fourth Military Medical University. METHODS： A total of 12 rapid retinal degeneration mice and 12 normal wild-type male Kunming mice were randomly assigned to experimental and control subgroups, respectively （n = 6）. Mice in the experimental group were exposed to rotary motion at a speed of 180°/s, 3 minutes per cycle, in an alternating clockwise/counterclockwise movement. Mice in the control group were not exposed to rotary motion. MAIN OUTCOME MEASURES： Differences in the number of Fos-positive neurons were determined in the vestibular nucleus, prepositus hypoglossal nucleus, inferior olive subnucleus beta, Kooy cap of the inferior olive medial nucleus, and the flocculus and paraflocculus of the cerebellum in rapid retinal degeneration mice and normal wild-type Kunming mice. RESULTS： The number of Fos-positive neurons was reduced in the prepositus hypoglossal nucleus and the Kooy cap of the inferior olive medial nucleus in the rapid retinal degeneration mice following 30 minutes of rotary motion in the experimental group, compared with the normal wild-type Kunming mice （P 〈 0.01）. There was no significant difference in Fos protein expression in the vestibular nucleus, inferior olive subnucleus beta, and the flocculus and paraflocculus of the cerebellum between the rapid retinal degeneration mice and normal wild-type Kunming mice. CONCLUSION： Visual information affected neuronal activation in the prepositus hypoglossal nucleus and the Kooy cap of the inferior olive medial nucleus in mice following rotary motion. The prepositus hypoglossal nucleus and the dorsal cap of Kooy of inferior olive medial nucleus were shown to be key integration regions of visual information and vestibular information in the central nervous system.

Autophagy dysregulation mediates the damage of high glucose to retinal pigment epithelium cells

AIM:To observe the role and mechanism of autophagy in retinal pigment epithelial cell(RPE)damaged by high glucose,so as to offer a new idea for the treatment of diabetic retinopathy(DR).METHODS:ARPE-19,a human RPE cell line cultured in vitro was divided into the normal control(NC),autophagy inhibitor 3-methyladenine(3-MA),high-glucose(HG),and HG+3-MA groups.Cell viability was detected by CCK-8 assay and the apoptosis rate was measured by flow cytometry.The protein expressions of apoptosis markers,including Bax,Bcl-2,and Caspase-3,as well as autophagy marker including microtubule-related protein 1 light chain 3(LC3),p62,and mechanistic target of rapamycin(m TOR)were detected by Western blotting.Autophagic flux was detected by transfection with Ad-m Cherry-GFP-LC3 B.RESULTS:Under high glucose conditions,the viability of ARPE-19 was decreased,and the apoptosis rate increased,the protein expressions of Bax,Caspase-3,and LC3-II/LC3-I were all increased and the expressions of Bcl-2,p62 and p-m TOR decreased,and autophagic flux was increased compared with that of the controls.Treatment with 3-MA reversed all these changes caused by high glucose.CONCLUSION:The current study demonstrates the mechanisms of cell damage of ARPE-19 through high glucose/m TOR/autophagy/apoptosis pathway,and new strategies for DR may be developed based on autophagy regulation to manage cell death of RPE cells.

Mitochondrial Oxidative Stress Enhances Vasoconstriction by Altering Calcium Homeostasis in Cerebrovascular Smooth Muscle Cells under Simulated Microgravity

Objective Exposure to microgravity results in postflight cardiovascular deconditioning in astronauts.Vascular oxidative stress injury and mitochondrial dysfunction have been reported during this process.To elucidate the mechanism for this condition,we investigated whether mitochondrial oxidative stress regulates calcium homeostasis and vasoconstriction in hindlimb unweighted(HU)rat cerebral arteries.Methods Three-week HU was used to simulate microgravity in rats.The contractile responses to vasoconstrictors,mitochondrial fission/fusion,Ca^(2+) distribution,inositol 1,4,5-trisphosphate receptor(IP3 R)abundance,and the activities of voltage-gated K+channels(KV)and Ca^(2+)-activated K+channels(BKCa)were examined in rat cerebral vascular smooth muscle cells(VSMCs).Results An increase of cytoplasmic Ca^(2+) and a decrease of mitochondrial/sarcoplasmic reticulum(SR)Ca^(2+) were observed in HU rat cerebral VSMCs.The abundance of fusion proteins(mitofusin 1/2[MFN1/2])and fission proteins(dynamin-related protein 1[DRP1]and fission-mitochondrial 1[FIS1])was significantly downregulated and upregulated,respectively in HU rat cerebral VSMCs.The cerebrovascular contractile responses to vasoconstrictors were enhanced in HU rats compared to control rats,and IP3 R protein/mRNA levels were significantly upregulated.The current densities and open probabilities of KV and BKCa decreased and increased,respectively.Treatment with the mitochondrial-targeted antioxidant mitoTEMPO attenuated mitochondrial fission by upregulating MFN1/2 and downregulating DRP1/FIS1.It also decreased IP3 R expression levels and restored the activities of the KV and BKCa channels.MitoTEMPO restored the Ca^(2+) distribution in VSMCs and attenuated the enhanced vasoconstriction in HU rat cerebral arteries.Conclusion The present results suggest that mitochondrial oxidative stress enhances cerebral vasoconstriction by regulating calcium homeostasis during simulated microgravity.

RIPK3 promotes hantaviral replication by restricting JAK-STAT signaling without triggering necroptosis

Hantaan virus(HTNV)is a rodent-borne virus that causes hemorrhagic fever with renal syndrome(HFRS),resulting in a high mortality rate of 15%.Interferons(IFNs)play a critical role in the anti-hantaviral immune response,and IFN pretreatment efficiently restricts HTNV infection by triggering the expression of a series of IFNstimulated genes(ISGs)through the Janus kinase-signal transducer and activator of transcription 1(JAK-STAT)pathway.However,the tremendous amount of IFNs produced during late infection could not restrain HTNV replication,and the mechanism remains unclear.Here,we demonstrated that receptor-interacting protein kinase 3(RIPK3),a crucial molecule that mediates necroptosis,was activated by HTNV and contributed to hantavirus evasion of IFN responses by inhibiting STAT1 phosphorylation.RNA-seq analysis revealed the upregulation of multiple cell death-related genes after HTNV infection,with RIPK3 identified as a key modulator of viral replication.RIPK3 ablation significantly enhanced ISGs expression and restrained HTNV replication,without affecting the expression of pattern recognition receptors(PRRs)or the production of type I IFNs.Conversely,exogenously expressed RIPK3 compromised the host's antiviral response and facilitated HTNV replication.RIPK3^(-/-)mice also maintained a robust ability to clear HTNV with enhanced innate immune responses.Mechanistically,we found that RIPK3 could bind STAT1 and inhibit STAT1 phosphorylation dependent on the protein kinase domain(PKD)of RIPK3 but not its kinase activity.Overall,these observations demonstrated a noncanonical function of RIPK3 during viral infection and have elucidated a novel host innate immunity evasion strategy utilized by HTNV.

Multi-Model Ensemble Deep Learning Method to Diagnose COVID-19 Using Chest Computed Tomography Images

Deep learning based analyses of computed tomography(CT)images contribute to automated diagnosis of COVID-19,and ensemble learning may commonly provide a better solution.Here,we proposed an ensemble learning method that integrates several component neural networks to jointly diagnose COVID-19.Two ensemble strategies are considered:the output scores of all component models that are combined with the weights adjusted adaptively by cost function back propagation;voting strategy.A database containing 8347 CT slices of COVID-19,common pneumonia and normal subjects was used as training and testing sets.Results show that the novel method can reach a high accuracy of 99.37%(recall:0.9981;precision:0.9893),with an increase of about 7% in comparison to single-component models.And the average test accuracy is 95.62%(recall:0.9587;precision:0.9559),with a corresponding increase of 5.2%.Compared with several latest deep learning models on the identical test set,our method made an accuracy improvement up to 10.88%.The proposed method may be a promising solution for the diagnosis of COVID-19.