Binding and molecular basis of the bat coronavirus RaTG13 virus to ACE2 in humans and other species.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been spreading worldwide, causing a global pandemic. Bat-origin RaTG13 is currently the most phylogenetically related virus. Here we obtained the complex structure of the RaTG13 receptor binding domain (RBD) with human ACE2 (hACE2) and evaluated binding of RaTG13 RBD to 24 additional ACE2 orthologs. By substituting residues in the RaTG13 RBD with their counterparts in the SARS-CoV-2 RBD, we found that residue 501, the major position found in variants of concern (VOCs) 501Y.V1/V2/V3, plays a key role in determining the potential host range of RaTG13. We also found that SARS-CoV-2 could induce strong cross-reactive antibodies to RaTG13 and identified a SARS-CoV-2 monoclonal antibody (mAb), CB6, that could cross-neutralize RaTG13 pseudovirus. These results elucidate the receptor binding and host adaption mechanisms of RaTG13 and emphasize the importance of continuous surveillance of coronaviruses (CoVs) carried by animal reservoirs to prevent another spillover of CoVs.

Atlas of currently available human neutralizing antibodies against SARS-CoV-2 and escape by Omicron sub-variants BA.1/BA.1.1/BA.2/BA.3.

SARS-CoV-2 Omicron variant has presented significant challenges to current antibodies and vaccines. Herein, we systematically compared the efficacy of 50 human monoclonal antibodies (mAbs), covering the seven identified epitope classes of the SARS-CoV-2 RBD, against Omicron sub-variants BA.1, BA.1.1, BA.2, and BA.3. Binding and pseudovirus-based neutralizing assays revealed that 37 of the 50 mAbs lost neutralizing activities, whereas the others displayed variably decreased activities against the four Omicron sub-variants. BA.2 was found to be more sensitive to RBD-5 antibodies than the other sub-variants. Furthermore, a quaternary complex structure of BA.1 RBD with three mAbs showing different neutralizing potencies against Omicron provided a basis for understanding the immune evasion of Omicron sub-variants and revealed the lack of G446S mutation accounting for the sensitivity of BA.2 to RBD-5 mAbs. Our results may guide the application of the available mAbs and facilitate the development of universal therapeutic antibodies and vaccines against COVID-19.

Host range and structural analysis of bat-origin RshSTT182/200 coronavirus binding to human ACE2 and its animal orthologs.

Bat-origin RshSTT182 and RshSTT200 coronaviruses (CoV) from Rhinolophus shameli in Southeast Asia (Cambodia) share 92.6% whole-genome identity with SARS-CoV-2 and show identical receptor-binding domains (RBDs). In this study, we determined the structure of the RshSTT182/200 receptor binding domain (RBD) in complex with human angiotensin-converting enzyme 2 (hACE2) and identified the key residues that influence receptor binding. The binding of the RshSTT182/200 RBD to ACE2 orthologs from 39 animal species, including 18 bat species, was used to evaluate its host range. The RshSTT182/200 RBD broadly recognized 21 of 39 ACE2 orthologs, although its binding affinities for the orthologs were weaker than those of the RBD of SARS-CoV-2. Furthermore, RshSTT182 pseudovirus could utilize human, fox, and Rhinolophus affinis ACE2 receptors for cell entry. Moreover, we found that SARS-CoV-2 induces cross-neutralizing antibodies against RshSTT182 pseudovirus. Taken together, these findings indicate that RshSTT182/200 can potentially infect susceptible animals, but requires further evolution to obtain strong interspecies transmission abilities like SARS-CoV-2.

Molecular basis of cross-species ACE2 interactions with SARS-CoV-2-like viruses of pangolin origin.

Pangolins have been suggested as potential reservoir of zoonotic viruses, including SARS-CoV-2 causing the global COVID-19 outbreak. Here, we study the binding of two SARS-CoV-2-like viruses isolated from pangolins, GX/P2V/2017 and GD/1/2019, to human angiotensin-converting enzyme 2 (hACE2), the receptor of SARS-CoV-2. We find that the spike protein receptor-binding domain (RBD) of pangolin CoVs binds to hACE2 as efficiently as the SARS-CoV-2 RBD in vitro. Furthermore, incorporation of pangolin CoV RBDs allows entry of pseudotyped VSV particles into hACE2-expressing cells. A screen for binding of pangolin CoV RBDs to ACE2 orthologs from various species suggests a broader host range than that of SARS-CoV-2. Additionally, cryo-EM structures of GX/P2V/2017 and GD/1/2019 RBDs in complex with hACE2 show their molecular binding in modes similar to SARS-CoV-2 RBD. Introducing the Q498H substitution found in pangolin CoVs into the SARS-CoV-2 RBD expands its binding capacity to ACE2 homologs of mouse, rat, and European hedgehog. These findings suggest that these two pangolin CoVs may infect humans, highlighting the necessity of further surveillance of pangolin CoVs.

One-Pot, Metal-Free Synthesis of Allyl Sulfones in Water.

A one-pot dehydration cross-coupling reaction between allyl alcohols and sodium sulfinates that provides allyl sulfones in good to excellent yields is presented. Its broad substrate scope includes symmetrical and asymmetrical α,α-diaryl- and α-aryl-substituted allylic alcohols and aryl and alkyl sodium sulfinates. For asymmetrical allylic substrates, the E isomer predominates with examples of excellent stereoselectivity. Control experiments provide the basis for a proposed radical-mediated mechanism. The metal-free procedure applies cheap and commercially available tetrabutylammonium tribromide as the catalyst and H2O as the solvent. Notable features of this simple, efficient, weakly toxic, and environmentally benign strategy include mild and convenient operating conditions and readily accessible starting materials.

Cross-species recognition of SARS-CoV-2 to bat ACE2.

The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as a major threat to global health. Although varied SARS-CoV-2-related coronaviruses have been isolated from bats and SARS-CoV-2 may infect bat, the structural basis for SARS-CoV-2 to utilize the human receptor counterpart bat angiotensin-converting enzyme 2 (bACE2) for virus infection remains less understood. Here, we report that the SARS-CoV-2 spike protein receptor binding domain (RBD) could bind to bACE2 from Rhinolophus macrotis (bACE2-Rm) with substantially lower affinity compared with that to the human ACE2 (hACE2), and its infectivity to host cells expressing bACE2-Rm was confirmed with pseudotyped SARS-CoV-2 virus and SARS-CoV-2 wild virus. The structure of the SARS-CoV-2 RBD with the bACE2-Rm complex was determined, revealing a binding mode similar to that of hACE2. The analysis of binding details between SARS-CoV-2 RBD and bACE2-Rm revealed that the interacting network involving Y41 and E42 of bACE2-Rm showed substantial differences with that to hACE2. Bats have extensive species diversity and the residues for RBD binding in bACE2 receptor varied substantially among different bat species. Notably, the Y41H mutant, which exists in many bats, attenuates the binding capacity of bACE2-Rm, indicating the central roles of Y41 in the interaction network. These findings would benefit our understanding of the potential infection of SARS-CoV-2 in varied species of bats.

Forensic Identification and Evaluation of 25 Obstetric Brachial Plexus Palsy Medical Damage Cases.

OBJECTIVES: To analyze the high risk factors of obstetric brachial plexus palsy (OBPP), and to explore how to evaluate the relationship between fault medical behavior and OBPP in the process of medical damage forensic identification. METHODS: A retrospective analysis was carried out on 25 cases of medical damage liability disputes related to OBPP from 2017 to 2021 in Beijing Fayuan Judicial Science Evidence Appraisal Center. The shortcomings of hospitals in birth weight assessment, delivery mode selection, labor process observation and shoulder dystocia management, and the causal relationship between them and the damage consequences of the children were summarized. RESULTS: Fault medical behavior was assessed as the primary cause in 2 cases, equal cause in 10 cases, secondary cause in 8 cases, minor cause in 1 case, no causal relationship in 1 case, and unclear causal force in 3 cases. CONCLUSIONS: In the process of forensic identification of OBPP, whether medical behaviors fulfill diagnosis and treatment obligations should be objectively analyzed from the aspects of prenatal evaluation, delivery mode notification, standardized use of oxytocin, standard operation of shoulder dystocia, etc. Meanwhile, it is necessary to fully consider the objective risk of different risk factors and the difficulty of injury prevention, and comprehensively evaluate the causal force of fault medical behavior in the damage consequences.

Two-stage deep learning method for sparse-view fluorescence molecular tomography reconstruction.

Fluorescence molecular tomography (FMT) is a preclinical optical tomographic imaging technique that can trace various physiological and pathological processes at the cellular or even molecular level. Reducing the number of FMT projection views can improve the data acquisition speed, which is significant in applications such as dynamic problems. However, a reduction in the number of projection views will dramatically aggravate the ill-posedness of the FMT inverse problem and lead to significant degradation of the reconstructed images. To deal with this problem, we have proposed a deep-learning-based reconstruction method for sparse-view FMT that only uses four perpendicular projection views and divides the image reconstruction into two stages: image restoration and inverse Radon transform. In the first stage, the projection views of the surface fluorescence are restored to eliminate the blur derived from photon diffusion through a fully convolutional neural network. In the second stage, another convolutional neural network is used to implement the inverse Radon transform between the restored projections from the first stage and the reconstructed transverse slices. Numerical simulation and phantom and mouse experiments are carried out. The results show that the proposed method can effectively deal with the image reconstruction problem of sparse-view FMT.

Image restoration for blurry optical images caused by photon diffusion with deep learning.

Optical macroscopic imaging techniques have shown great significance in the investigations of biomedical issues by revealing structural or functional information of living bodies through the detection of visible or near-infrared light derived from different mechanisms. However, optical macroscopic imaging techniques suffer from poor spatial resolution due to photon diffusion in biological tissues. This dramatically restricts the application of optical imaging techniques in numerous situations. In this paper, an image restoration method based on deep learning is proposed to eliminate the blur caused by photon diffusion in optical macroscopic imaging. Two blurry images captured at orthogonal angles are used as the additional information to ensure the uniqueness of the solution and restore the small targets at deep locations. Then a fully convolutional neural network is proposed to accomplish the image restoration, which consists of three sectors: V-shaped network for central view, V-shaped network for side views, and synthetical path. The two V-shaped networks are concatenated to the synthetical path with skip connections to generate the output image. Simulations as well as phantom and mouse experiments are implemented. Results indicate the effectiveness of the proposed method.

Association of polycyclic aromatic hydrocarbons exposure with child neurodevelopment and adult emotional disorders: A meta-analysis study.

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) have been demonstrated to be neurotoxic. OBJECTIVES: To summarize the existing epidemiological studies to quantify the effects of PAHs exposure on child neurodevelopment and adult emotional disorders. DATA SOURCES AND STUDY ELIGIBILITY CRITERIA: We conducted a systematic literature search for studies of child neurodevelopment and adult emotional disorders published in English up to April 2022 in the databases of PubMed, Web of Science and Embase using combinations of MeSH terms and Entry terms, and the articles were filtered out according to data availability. A variety of common PAHs were included in the meta-analysis: 1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 3-hydroxyfluorene, 9-hydroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, 4-hydroxyphenanthrene, 9-hydroxyphenanthrene, 1-hydroxypyrene and benzoapyrene (BaP). STUDY EVALUATION AND SYNTHESIS METHODS: We extracted the content of each article, summarized its design characteristics and performed quality evaluation. We combined the odds ratio (OR) available in various studies to obtain the risk of PAHs exposure and adaptive, language, social, attention, motor skills and child depression/anxiety in children ≤ 15 years old. In addition, we also conducted a meta-analysis on the relationship between PAHs exposure and the risk of depression in adults. RESULTS: We included a total of 16 epidemiological studies (4 cross-sectional studies and 12 cohort studies). The sample size of all included studies ranged from 110 to 9625. Prenatal exposure to PAHs was found to be associated with increased risk of social behavior (OR = 1.60, 95% CI: 1.00-2.54), attention (OR = 2.99, 95% CI: 1.48-6.02), motor skill problems (OR = 1.91, 95% CI: 1.27-2.86) and any adverse neurodevelopmental outcome in children (OR = 2.10, 95% CI: 1.69-2.62). In addition, we found that PAHs exposure could increase the risk of adult depression, with 2-hydroxyfluorene exposure showing the highest combined OR (OR = 1.48, 95% CI: 1.10-2.00). CONCLUSIONS: The results suggested that PAHs exposure are associated with increased risk of child neurodevelopment and adult depression. The neurotoxic effects of PAHs exposure in human being should be paid more attention. The results suggested that PAHs exposure are associated with increased risk of child neurodevelopment and adult depression. The neurotoxic effects of PAHs exposure in human being should be paid more attention. Steps should be taken to enhance the biomonitoring of PAHs and to reduce the exposure in general population.

Aggregation of high-frequency RBD mutations of SARS-CoV-2 with three VOCs did not cause significant antigenic drift.

Variants of SARS-CoV-2 continue to emerge, posing great challenges in outbreak prevention and control. It is important to understand in advance the impact of possible variants of concern (VOCs) on infectivity and antigenicity. Here, we constructed one or more of the 15 high-frequency naturally occurring amino acid changes in the receptor-binding domain (RBD) of Alpha, Beta, and Gamma variants. A single mutant of A520S, V367F, and S494P in the above three VOCs enhanced infectivity in ACE2-overexpressing 293T cells of different species, LLC-MK2 and Vero cells. Aggregation of multiple RBD mutations significantly reduces the infectivity of the possible three VOCs. Regarding neutralization, it is noteworthy that E484K, N501Y, K417N, and N439K predispose to monoclonal antibodies (mAbs) protection failure in the 15 high-frequency mutations. Most importantly, almost all possible VOCs (single RBD mutation or aggregation of multiple mutations) showed no more than a fourfold decrease in neutralizing activity with convalescent sera, vaccine sera, and immune sera of guinea pigs with different immunogens, and no significant antigenic drift was formed. In conclusion, our pseudovirus results could reduce the concern that the aggregation of multiple high-frequency mutations in the RBD of the spike protein of the three VOCs would lead to severe antigenic drift, and this would provide value for vaccine development strategies.

Detection and genetic characteristics of porcine circovirus type 2 and 3 in Henan province of China.

PCV2 is one of the most economically important viral agents in swine worldwide. Recently, PCV3 has been frequently reported, and the co-infection of PCV2 and PCV3 is common in China. In order to explore the distribution, epidemiology and genetic diversity of PCV2 and PCV3, a total of 1,760 clinical tissue samples were randomly collected from 18 different regions in Henan province of China from October 2018 to September 2019 and screened for the presence of PCV2 and PCV3 by a duplex real-time PCR assay. The results showed that the positive rates of PCV2 and PCV3 were 72.90% and 5.17% respectively, and the co-infection rate of the two viruses was 3.64%. PCV2 and PCV3 are prevalent all year round. The prevalence of PCV2 in diseased pigs was 83.98%, higher than that in slaughterhouse pigs, while the prevalence of PCV3 in diseased pigs was 2.16%, slightly lower than that in slaughterhouse pigs. Furthermore, the complete genomes of 14 PCV2 and 3 PCV3 strains were obtained, among which 1 belonged to PCV2a, 5 belonged to PCV2b and 8 belonged to PCV2d. A new variant strain (XX2) might escape the host immune system. The phylogenetic analysis of PCV3 showed high nucleotide identity (>98%) between sequences obtained in this study and reference sequences. The results of this study might enrich the epidemiological data of PCV2 and PCV3 in Henan province and provide reference information for the comprehensive prevention and control of PCVAD.

Identification of the defense-related gene VdWRKY53 from the wild grapevine Vitis davidii using RNA sequencing and ectopic expression analysis in Arabidopsis.

BACKGROUND: Grapevine is an important fruit crop grown worldwide, and its cultivars are mostly derived from the European species Vitis vinifera, which has genes for high fruit quality and adaptation to a wide variety of climatic conditions. Disease resistance varies substantially across grapevine species; however, the molecular mechanisms underlying such variation remain uncharacterized. RESULTS: The anatomical structure and disease symptoms of grapevine leaves were analyzed for two grapevine species, and the critical period of resistance of grapevine to pathogenic bacteria was determined to be 12 h post inoculation (hpi). Differentially expressed genes (DEGs) were identified from transcriptome analysis of leaf samples obtained at 12 and 36 hpi, and the transcripts in four pathways (cell wall genes, LRR receptor-like genes, WRKY genes, and pathogenesis-related (PR) genes) were classified into four co-expression groups by using weighted correlation network analysis (WGCNA). The gene VdWRKY53, showing the highest transcript level, was introduced into Arabidopsis plants by using a vector containing the CaMV35S promoter. These procedures allowed identifying the key genes contributing to differences in disease resistance between a strongly resistant accession of a wild grapevine species Vitis davidii (VID) and a susceptible cultivar of V. vinifera, 'Manicure Finger' (VIV). Vitis davidii, but not VIV, showed a typical hypersensitive response after infection with a fungal pathogen (Coniella diplodiella) causing white rot disease. Further, 20 defense-related genes were identified, and their differential expression between the two grapevine species was confirmed using quantitative real-time PCR analysis. VdWRKY53, showing the highest transcript level, was selected for functional analysis and therefore over-expressed in Arabidopsis under the control of the CaMV35S promoter. The transgenic plants showed enhanced resistance to C. diplodiella and to two other pathogens, Pseudomonas syringae pv. tomato DC3000 and Golovinomyces cichoracearum. CONCLUSION: The consistency of the results in VID and transgenic Arabidopsis indicated that VdWRKY53 might be involved in the activation of defense-related genes that enhance the resistance of these plants to pathogens. Thus, the over-expression of VdWRKY53 in transgenic grapevines might improve their resistance to pathogens.

Berberine demonstrates anti-inflammatory properties in Helicobacter pylori-infected mice with chronic gastritis by attenuating the Th17 response triggered by the B cell-activating factor.

Berberine (BBR) is an isoquinoline alkaloid derived from various medicinal herbs. Previous studies have suggested that BBR exerts antimicrobial, antitumor, and antidiabetic effects and can be used to treat Helicobacter pylori-induced chronic gastritis. However, the exact mechanism by which BBR inhibits H. pylori infection is not fully understood. We investigated the anti-inflammatory properties and potential mechanism of BBR in H. pylori-infected mice with chronic gastritis. We found that BBR can suppress the expression of pro-inflammatory genes IL-6, TGF-ß, and IL-1ß and upregulate anti-inflammatory gene IL-10 expression in the mucosa and RAW 264.7 macrophages. Exposure to BBR also reduced the expression and accumulation of IL-17 in the mucosa and CD4+ T cells activated by anti-CD3 and anti-CD28, and it decreased the frequency of IL-17-producing CD4+ T cells. B cell-activating factor (BAFF) production was inhibited by BBR and by cultured dendritic and CD4+ T cells. Furthermore, we demonstrated that BAFF can trigger the Th17 response by promoting the production of pro-Th17 cytokines IL-6, TGF-ß, and IL-1ß, which are strongly associated with the anti-inflammatory role of BBR in chronic gastritis caused by H. pylori. In conclusion, we determined that BBR has anti-inflammatory effects on H. pylori-induced chronic gastritis by attenuating the BAFF-triggered Th17 response.

Nacre-like surface nanolaminates enhance fatigue resistance of pure titanium.

Fatigue failure is invariably the most crucial failure mode for metallic structural components. Most microstructural strategies for enhancing fatigue resistance are effective in suppressing either crack initiation or propagation, but often do not work for both synergistically. Here, we demonstrate that this challenge can be overcome by architecting a gradient structure featuring a surface layer of nacre-like nanolaminates followed by multi-variant twinned structure in pure titanium. The polarized accommodation of highly regulated grain boundaries in the nanolaminated layer to cyclic loading enhances the structural stability against lamellar thickening and microstructure softening, thereby delaying surface roughening and thus crack nucleation. The decohesion of the nanolaminated grains along horizonal high-angle grain boundaries gives rise to an extraordinarily high frequency (≈1.7 × 103 times per mm) of fatigue crack deflection, effectively reducing fatigue crack propagation rate (by 2 orders of magnitude lower than the homogeneous coarse-grained counterpart). These intriguing features of the surface nanolaminates, along with the various toughening mechanisms activated in the subsurface twinned structure, result in a fatigue resistance that significantly exceeds those of the homogeneous and gradient structures with equiaxed grains. Our work on architecting the surface nanolaminates in gradient structure provides a scalable and sustainable strategy for designing more fatigue-resistant alloys.

Risk factors related to low-level viraemia in chronic hepatitis B patients receiving entecavir treatment.

Background: About 20% of on-treatment patients with chronic hepatitis B (CHB) experienced low-level viraemia (LLV), which is associated with persistent low-grade inflammation, fibrosis progression, and increased risk of hepatocellular carcinoma. We aimed to investigate the high-risk factors related to LLV. Methods: In this retrospective study, patients receiving entecavir (ETV) treatment from January 2018 to January 2023 were enrolled, and were divided into a LLV (HBV DNA 20-2000 IU/mL) cohort and a complete virological response (CVR) (HBV DNA < 20 IU/mL) cohort according to the virological response at week 48 posttreatment. Treatment baseline characteristics were retrieved from electronic medical records. Multivariate logistic regression was performed. Results: Totally, 1653 patients were enrolled, male patients accounted for 73.0%; the median age was 44 years; the mean HBV DNA level was 5.9 Log10 IU/ml. Among them, 472 (28.6%) experienced LLV. Multivariate analysis showed that HBeAg positivity (OR = 2.650, 95% CI: 2.000-3.511, p < 0.001), HBV DNA ≥ 6.0 Log10 IU/mL (OR = 1.370, 95% CI: 1.054-1.780, p = 0.019), qHBsAg ≥ 9000 IU/mL (OR = 4.472, 95% CI: 3.410-5.866, p < 0.001), cirrhosis (OR = 1.650, 95% CI: 1.234-2.207, P = 0.001), LSM ≥ 13.0 kPa (OR = 1.644, 95% CI: 1.203-2.246, p = 0.002), and PLT < 100×109/L (OR = 1.450, 95% CI: 1.094-1.922, p = 0.010) at baseline were related to the development of LLV. Conclusions: High HBV DNA/HBsAg quantification/LSM, low PLT, HBeAg positivity, and liver cirrhosis were high-risk factors associated with LLV in patients receiving entecavir treatment.

Analysis of Influencing Factors and Mechanism of Farmers' Green Production Behaviors in China.

The green production behavior of pig farmers is the basis for high-quality development in animal husbandry. In order to solve the problem of poor green production behaviors in small- and medium-sized pig farmers, it is necessary to analyze the influencing factors and how they interact with each other. The Rational Peasant Theory and Prospect Theory were used in this paper to analyze the occurrence motivation of the green production behaviors of small- and medium-sized pig farmers. The Logit model and the ISM analysis method were used to test the influencing factors and their mechanisms. This was conducted using data from a study of 747 small- and medium-sized pig farmers in Henan Province. The results show that the green production behaviors of small- and medium-sized pig farmers are motivated by internal expected return, affected by the monitoring pressure from external stakeholders and limited by their own resource capacity; the influencing factors of different green production behaviors are different, and there are more influencing factors of scientific disease control, standardized management and waste recycling than of rational feeding. The following shows how the influencing factors on pig farmers' green production behavior interact with one another: level of education → external pressure, farming conditions and operating characteristics → cognition of return → green production behavior (i.e., cognition of return is the direct factor; external pressure, farming conditions and operating characteristics are indirect factors; and level of education is the underlying factor). Some measures should be implemented to promote green production behaviors, such as the continuation of the support for green production, the strengthening of supervision and publicity, the increasing of investment in technology and equipment, and the improving of the green production literacy of farmers. In conclusion, this paper deepens the understanding of the mechanism of green production behaviors of small- and medium-sized pig farmers, and provides the theoretical basis and concrete measures for the government and for pig farmers.

Manganese-induced PINK1 S-nitrosylation exacerbates nerve cell damage by promoting ZNF746 repression of mitochondrial biogenesis.

Occupational exposure and non-occupational exposure to excessive levels of manganese (Mn) result in neuronal cell damage through mitochondrial dysfunction. The functional integrity of mitochondria is maintained by mitophagy and mitochondrial biogenesis. Although Mn-induced S-nitrosylation of PTEN-induced putative kinase 1 (PINK1) can interfere with mitophagy, its effect on mitochondrial biogenesis remains unclear. In this study, we established a rat model of Mn poisoning or "manganism" to examine the relationship between PINK1 S-nitrosylation and impairment of mitochondrial biogenesis, and found that treatment with 60 mg/kg Mn induced marked neurobehavioral abnormalities in rats and significantly increased the S-nitrosylation level of PINK1. We also found that the nuclear-encoded peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PPARGC1A)-mediated mitochondrial biogenesis was significantly upregulated in rats treated with 15 and 30 mg/kg Mn, and downregulated in rats treated with 60 mg/kg Mn. We further investigated the role of S-nitrosylated PINK1 and its molecular mechanism in the high-dose Mn-mediated impairment of mitochondrial biogenesis in primary cultured neurons treated with the nitric oxide synthase 2 (NOS2) inhibitor 1400 W. Our results revealed that the PPARGC1A-mediated mitochondrial biogenesis was upregulated in neurons treated with 100 µM, but downregulated in neurons treated with 200 µM Mn, which was similar to the in vivo results. However, treatment with 1400W could effectively prevent the 200 µM Mn-mediated impairment of mitochondrial biogenesis by suppressing nitric oxide (NO)-mediated PINK1 S-nitrosylation and rescuing Parkin-interacting substrate (PARIS, ZNF746) degradation, thereby upregulating mitochondrial biogenesis via PPARGC1A. These findings demonstrated that S-nitrosylation of PINK1 and subsequent prevention of ZNF746 degradation were crucial signaling processes involved in the Mn-mediated impairment of mitochondrial biogenesis, which might serve as an underlying mechanism of Mn-induced neurotoxicity. Furthermore, this study provided a reliable target for the prevention and treatment of manganism.

Manganese triggers persistent activation of the integrated stress response by inhibition of SIRT1 on deacetylation of GADD34.

Overexposure to manganese (Mn) is conducive to neurodegenerative diseases and neuronal injury. Persistent activation of the integrated stress response (ISR) has a substantial impact on the etiology of neurodegenerative disorders by interfering with intracellular homeostasis. Nevertheless, the precise mechanism through which ISR engages in Mn-related neurotoxicity remains unclear. Sirtuin 1 (SIRT1), a typical NAD+-dependent protein deacetylase, which is known to participate in Mn-induced neuronal damage. Therefore, the aim of our study was to clarify how SIRT1 regulates persistent ISR activation in mouse hippocampal neuronal cells (HT-22 cells) exposed to various concentrations of Mn. We discovered that persistent ISR activation was engaged in Mn-triggered mitochondrial and exogenous apoptotic signaling pathways, which was attributed to the excessive phosphorylation of eukaryotic translation initiation factor 2α (eIF2α). Growth arrest and DNA damage-inducible protein 34 (GADD34) is known to be responsible for down-regulating the phosphorylation of eIF2α. However, Mn promoted GADD34 protein expression and its acetylation level. We further investigated the effect of SIRT1 on the acetylation of GADD34 by overexpressing and silencing SIRT1. We discovered that SIRT1 activation significantly declined the acetylation level of GADD34, thus alleviating persistent ISR activation-mediated neuronal apoptosis in HT-22 cells-treated with Mn. In summary, these results suggested that Mn induced persistent activation of the ISR by inhibition of SIRT1 on deacetylation of GADD34.