Microglia-regulated activation of CD4+ T cells in the development of experimental autoimmune encephalomyelitis

Autoantigen-specific encephalitogenic T cells gaining access to the central nervous system (CNS) and leading to self-destructive inflammation are the critical driving force for multiple sclerosis (MS). It has been shown that peripherally primed T cells have to infiltrate into the CNS and to get reactivated by antigen-presenting cells (APCs) in order to induce inflammation in experimental autoimmune encephalomyelitis (EAE), an animal model of MS. The contributions of macrophages and dendritic cells as APCs at the border between CNS and periphery were shown. However, antigen presentation in CNS remains largely undefined; especially the function of glia cells as APCs remains elusive. Microglia are the only CNS-resident immune cells, thus their potential function in regulating T cell activation cannot be overlooked. In this study, we determined to understand the relationship between microglia and T cells. Live imaging revealed that naive microglia or LPS-stimulated microglia cannot induce the activation of NFAT-GFP-expressing MBP-specific T cells (TMBP-NFAT-GFP cells) and NFAT-GFP-expressing OVA-specific T cells (TOVA-NFAT-GFP cells), indicated by translocation of NFAT-GFP from cytosol into the nucleus. Interestingly, Interferon-γ (IFN-γ)-stimulated microglia significantly induced activation of both TMBP-NFAT-GFP cells and TOVA-NFAT-GFP cells even without the presence of cognate antigen, indicating antigen-independent T cell activation by microglia, which are regulated by IFN-γ. In addition, by comparing macrophages and microglia in the CNS of rats with EAE, we showed that macrophages were more efficient APCs than microglia. Interestingly, IFN-γ-stimulated microglia and microglia from EAE rats showed similar T cell stimulation capacity. IFN-γ, a signature cytokine of TH1 cells, was highly upregulated in both TMBP cells and TOVA cells after co-culturing with naive microglia even without the presence of cognate antigens, suggesting microglia regulate T cell activation antigen-independently. Furthermore, we evaluated different cytokine expression in TMBP cells and TOVA cells after co-culturing with microglia and found two innate cytokines, tumor necrosis factor α (TNF-α) and interleukin-1β (IL-1β), were highly upregulated. The induction of these cytokines required direct contact of T cells and microglia. Intriguingly, knockout TNF-α in T cells by using CRISPR/Cas gene editing showed that TNF signaling regulated IL-1β production. Moreover, IL-2R, OX-40 and major histocompatibility complex class II (MHCII) were highly upregulated on both TMBP cells and TOVA cells after co-culturing with microglia in absence of antigen, which further support the idea that microglia regulate T cell activation antigen-independently. Beside of microglia, we looked at whether astrocytes activate T cells as similar as microglia. However, astrocytes were not as strong as microglia in inducing T cell activation. To characterize the transcriptome profile of microglia and macrophages at the early stage of EAE, we performed RNA-sequencing analysis. Compared to naive microglia, microglia from EAE rats showed strong enrichment of genes associated with IFN-γ signaling, suggesting that microglia are influenced by TH1 cells. Moreover, microglia strongly upregulated chemokines such as Cxcl9, Cxcl10, Cxcl11 and Ccl5 which are important for T cell recruitment into the CNS. Although macrophages have a higher T cell stimulating capacity than microglia, at the very early stage of EAE, microglia are the main myeloid cells in the CNS that activate T cells before macrophages penetrate into the CNS. In summary, our study showed that in addition to antigen-dependent manner, microglia can regulate T cell differentiation and activation antigen-independently. Although macrophages showed higher T cell activating capacity, their number is low at early stages of EAE. At that time point, microglia can stimulate T cells and induce production of inflammatory cytokines. In addition, as results of interaction with T cells, microglia produced chemokines, which could be important for the further recruitment of T cells and macrophages

The impact of organizational stigmatization on the operational risk and performance of overseas subsidiaries: empirical evidence from Chinese multinational enterprises

This study used the global database of events, language, and tone of international public opinion big data to measure organizational stigmatization against China. It then used an econometric model to investigate the impact of organizational stigmatization on the operational risk and performance of overseas subsidiaries of Chinese multinational enterprises. The results show that: (1) organizational stigmatization increases overseas subsidiaries’ operational risk and reduces their operational performance, which is more evident in overseas subsidiaries of state-owned enterprises; (2) the host country’s political stability weakens the organizational stigmatization’s positive impact on overseas subsidiaries’ operational risk. The geographical distance between the home and host countries strengthens organizational stigmatization’s positive impact on overseas subsidiaries’ operational risk; (3) the host country’s political stability and the geographical distance between the home and host countries have no moderating effect on organizational stigmatization and overseas subsidiaries’ operational performance; and (4) organizational stigmatization by the host country reduces overseas subsidiaries’ operational performance via the channel of operational risk. This study innovates the measurement method of organizational stigmatization and lays the foundation for investigating the microeconomic impact of organizational stigmatization from the perspective of overseas subsidiaries

Pathogenic Mutations Differentially Regulate Cell-to-Cell Transmission of α-Synuclein

Recent studies suggest that the cell-to-cell spread of pathological α-synuclein (α-syn) plays important roles in the development of Parkinson’s disease (PD). PD patients who carry α-syn gene mutations often have an earlier onset and more severe clinical symptoms and pathology than sporadic PD cases who carry the wild-type (WT) α-syn gene. However, the molecular mechanism by which α-syn gene mutations promote PD remains unclear. Here, we hypothesized that pathogenic mutations facilitate the intercellular transfer and cytotoxicity of α-syn, favoring an early disease onset and faster progression. We investigated the effects of eight known pathogenic mutations in human α-syn (A18T, A29S, A30P, E46K, H50Q, G51D, A53E, and A53T) on its pathological transmission in terms of secretion, aggregation, intracellular level, cytotoxicity, seeding, and induction of neuroinflammation in SH-SY5Y neuroblastoma cells, cultured rat neurons, and microglia, and the rat substantia nigra pars compacta. We found that 2 of the 8 mutations (H50Q and A53T) significantly increased α-syn secretion while 6 mutations (A18T, A29S, A30P, G51D, A53E, and E46K) tended to enhance it. In vitroα-syn aggregation experiments showed that H50Q promoted while G51D delayed aggregation most strongly. Interestingly, 3 mutations (E46K, H50Q, and G51D) greatly increased the intracellular α-syn level when cultured cells were treated with preformed α-syn fibrils (PFFs) compared with the WT, while the other 5 had no effect. We also demonstrated that H50Q, G51D, and A53T PFFs, but not E46K PFFs, efficiently seeded in vivo and acutely induced neuroinflammation in rat substantia nigra pars compacta. Our data indicate that pathogenic mutations augment the prion-like spread of α-syn at different steps and blockade of this pathogenic propagation may serve as a promising therapeutic intervention for PD

A comparative study of genotyping and antimicrobial resistance between carbapenem-resistant Klebsiella pneumoniae and Acinetobacter baumannii isolates at a tertiary pediatric hospital in China

BackgroundCarbapenem-resistant Klebsiella pneumoniae (CRKP) clinical isolations have rapidly increased in pediatric patients. To investigate a possible health care-associated infections of CRKP in a tertiary pediatric hospital, the circulating clones and carbapenem-resistant pattern between CRKP and carbapenem-resistant Acinetobacter baumannii (CRAB) isolates were compared to classify their epidemiological characteristics. The results will help to identify the epidemic pattern of the CRKP transmission in the hospital.MethodsNinety-six CRKP and forty-eight CRAB isolates were collected in Kunming Children’s Hospital from 2019 through 2022. These isolates were genotyped using repetitive extragenic palindromic-PCR (REP-PCR). Carbapenemase phenotypic and genetic characterization were investigated using a disk diffusion test and singleplex PCR, respectively. In addition, these characteristics of the two pathogens were compared.ResultsThe rates of CRKP and CRAB ranged from 15.8% to 37.0% at the hospital. Forty-nine and sixteen REP genotypes were identified among the 96 and 48 CRKP and CRAB isolates tested, respectively. The CRKP isolates showed more genetic diversity than the CRAB isolates. Of the 96 CRKP isolates, 69 (72%) produced Class B carbapenemases. However, all 48 CRAB isolates produced Class D carbapenemase or extended-spectrum β-lactamases (ESBL) combined with the downregulation of membrane pore proteins. Furthermore, the carbapenemase genes blaKPC, blaIMP, and blaNDM were detected in CRKP isolates. However, CRAB isolates were all positive for the blaVIM, blaOXA-23, and blaOXA-51 genes.ConclusionsThese CRKP isolates exhibited different biological and genetic characteristics with dynamic changes, suggesting widespread communities. Continuous epidemiological surveillance and multicenter research should be carried out to strengthen the prevention and control of infections