Cardiolipin interacts with beta‐2‐glycoprotein I and forms an open conformation–Mechanisms analyzed using hydrogen/deuterium exchange

Beta‐2‐glycoprotein I (β₂GPI) is the major antigen for the antiphospholipid antibodies in the antiphospholipid syndrome. The exposed epitope in domain I of β₂GPI can be recognized by the anti‐β₂GPI antibody. Here, we prepared the anionic di‐oleoyl‐phosphatidylserine (DOPS) and cardiolipin (CL) liposomes to interact with the β₂GPI. The conformational changes of β₂GPI upon binding with the liposomes were analyzed using hydrogen/deuterium exchange mass spectrometry. The exchange level of sequences 21–27 significantly increased after β₂GPI had interacted with DOPS. This change indicated a reduced interaction between domain I and domain V, inferring to a protrusion of the sequences 21–27 from the ring conformation. After β₂GPI had interacted with CL for 30 min, the exchange levels in 4 of the 5 domains increased significantly. The deuteration levels of sequences 1–20, 21–27, 196–205, 273–279 and 297–306 increased, suggesting that these regions had become more exposed, and the domain I was no longer in contact with domain V. The increasing deuteration levels in sequences 70–86, 153–162, 191–198, 196–205 and 273–279 indicated β₂GPI undergoing conformational changes to expose these inner regions, suggesting a structural transition. Overall, DOPS and CL induced minor conformational changes of β₂GPI at sequences 21–27 and forms an intermediate conformation after 10 min of interaction. After a complete protein–lipid interaction, high negatively charged CL membrane induced a major conformation transition of β₂GPI.     

High‐resolution analysis of the conformational transition of pro‐apoptotic Bak at the lipid membrane

Permeabilization of the outer mitochondrial membrane by pore‐forming Bcl2 proteins is a crucial step for the induction of apoptosis. Despite a large set of data suggesting global conformational changes within pro‐apoptotic Bak during pore formation, high‐resolution structural details in a membrane environment remain sparse. Here, we used NMR and HDX‐MS (Hydrogen deuterium exchange mass spectrometry) in lipid nanodiscs to gain important high‐resolution structural insights into the conformational changes of Bak at the membrane that are dependent on a direct activation by BH3‐only proteins. Furthermore, we determined the first high‐resolution structure of the Bak transmembrane helix. Upon activation, α‐helix 1 in the soluble domain of Bak dissociates from the protein and adopts an unfolded and dynamic potentially membrane‐bound state. In line with this finding, comparative protein folding experiments with Bak and anti‐apoptotic BclxL suggest that α‐helix 1 in Bak is a metastable structural element contributing to its pro‐apoptotic features. Consequently, mutagenesis experiments aimed at stabilizing α‐helix 1 yielded Bak variants with delayed pore‐forming activity. These insights will contribute to a better mechanistic understanding of Bak‐mediated membrane permeabilization.     

3,6'‐disinapoyl sucrose attenuates Aβ1‐42‐ induced neurotoxicity in Caenorhabditis elegans by enhancing antioxidation and regulating autophagy

The aggregation of β‐amyloid (Aβ) has the neurotoxicity, which is thought to play critical role in the pathogenesis of Alzheimer''s disease (AD). Inhibiting Aβ deposition and neurotoxicity has been considered as an important strategy for AD treatment. 3,6''‐Disinapoyl sucrose (DISS), one of the oligosaccharide esters derived from traditional Chinese medicine Polygalae Radix, possesses antioxidative activity, neuroprotective effect and anti‐depressive activity. This study was to explore whether DISS could attenuate the pathological changes of Aβ_1‐42 transgenic Caenorhabditis elegans (C. elegans). The results showed that DISS (5 and 50 μM) treatment significantly prolonged the life span, increased the number of egg‐laying, reduced paralysis rate, decreased the levels of lipofuscin and ROS and attenuated Aβ deposition in Aβ_1‐42 transgenic C. elegans. Gene analysis showed that DISS could up‐regulate the mRNA expression of sod‐3, gst‐4, daf‐16, bec‐1 and lgg‐1, while down‐regulate the mRNA expression of daf‐2 and daf‐15 in Aβ_1‐42 transgenic C. elegans. These results suggested that DISS has the protective effect against Aβ_1‐42‐induced pathological damages and prolongs the life span of C. elegans, which may be related to the reduction of Aβ deposition and neurotoxicity by regulating expression of genes related to antioxidation and autophagy.     

Knockdown of circular RNA VANGL1 inhibits TGF‐β‐induced epithelial‐mesenchymal transition in melanoma cells by sponging miR‐150‐5p

Melanoma is one of the most aggressive and life‐threatening skin cancers, and in this research, we aimed to explore the functional role of circular RNA VANGL1 (circVANGL1) in melanoma progression. The expression levels of circVANGL1 were observed to be significantly increased in clinical melanoma tissues and cell lines. Moreover, circVANGL1 knockdown suppressed, while circVANGL1 overexpression promoted the proliferation, migration and invasion abilities of melanoma cells. Further investigations confirmed the direct binding relation between circVANGL1 and miR‐150‐5p in melanoma, and restoration of miR‐150‐5p blocked the effects of circVANGL1 overexpression in melanoma cells. We further found that circVANGL1 was up‐regulated by TGF‐β treatment, and the enhanced EMT of TGF‐β‐treated melanoma cells was blocked by circVANGL1 knockdown. In conclusion, these results indicated that circVANGL1 might serve as a promising therapeutic target for melanoma.     

The conserved C2 phospholipid‐binding domain in Delta contributes to robust Notch signalling

Accurate Notch signalling is critical for development and homeostasis. Fine‐tuning of Notch–ligand interactions has substantial impact on signalling outputs. Recent structural studies have identified a conserved N‐terminal C2 domain in human Notch ligands which confers phospholipid binding in vitro. Here, we show that Drosophila ligands Delta and Serrate adopt the same C2 domain structure with analogous variations in the loop regions, including the so‐called β1‐2 loop that is involved in phospholipid binding. Mutations in the β1‐2 loop of the Delta C2 domain retain Notch binding but have impaired ability to interact with phospholipids in vitro. To investigate its role in vivo, we deleted five residues within the β1‐2 loop of endogenous Delta. Strikingly, this change compromises ligand function. The modified Delta enhances phenotypes produced by Delta loss‐of‐function alleles and suppresses that of Notch alleles. As the modified protein is present on the cell surface in normal amounts, these results argue that C2 domain phospholipid binding is necessary for robust signalling in vivo fine‐tuning the balance of trans and cis ligand–receptor interactions.     

TIFA has dual functions in Helicobacter pylori‐induced classical and alternative NF‐κB pathways

Helicobacter pylori infection constitutes one of the major risk factors for the development of gastric diseases including gastric cancer. The activation of nuclear factor‐kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) via classical and alternative pathways is a hallmark of H. pylori infection leading to inflammation in gastric epithelial cells. Tumor necrosis factor receptor‐associated factor (TRAF)‐interacting protein with forkhead‐associated domain (TIFA) was previously suggested to trigger classical NF‐κB activation, but its role in alternative NF‐κB activation remains unexplored. Here, we identify TRAF6 and TRAF2 as binding partners of TIFA, contributing to the formation of TIFAsomes upon H. pylori infection. Importantly, the TIFA/TRAF6 interaction enables binding of TGFβ‐activated kinase 1 (TAK1), leading to the activation of classical NF‐κB signaling, while the TIFA/TRAF2 interaction causes the transient displacement of cellular inhibitor of apoptosis 1 (cIAP1) from TRAF2, and proteasomal degradation of cIAP1, to facilitate the activation of the alternative NF‐κB pathway. Our findings therefore establish a dual function of TIFA in the activation of classical and alternative NF‐κB signaling in H. pylori‐infected gastric epithelial cells.     

Neuronal α‐amylase is important for neuronal activity and glycogenolysis and reduces in presence of amyloid beta pathology

Recent studies indicate a crucial role for neuronal glycogen storage and degradation in memory formation. We have previously identified alpha‐amylase (α‐amylase), a glycogen degradation enzyme, located within synaptic‐like structures in CA1 pyramidal neurons and shown that individuals with a high copy number variation of α‐amylase perform better on the episodic memory test. We reported that neuronal α‐amylase was absent in patients with Alzheimer''s disease (AD) and that this loss corresponded to increased AD pathology. In the current study, we verified these findings in a larger patient cohort and determined a similar reduction in α‐amylase immunoreactivity in the molecular layer of hippocampus in AD patients. Next, we demonstrated reduced α‐amylase concentrations in oligomer amyloid beta 42 (Aβ₄₂) stimulated SH‐SY5Y cells and neurons derived from human‐induced pluripotent stem cells (hiPSC) with PSEN1 mutation. Reduction of α‐amylase production and activity, induced by siRNA and α‐amylase inhibitor Tendamistat, respectively, was further shown to enhance glycogen load in SH‐SY5Y cells. Both oligomer Aβ₄₂ stimulated SH‐SY5Y cells and hiPSC neurons with PSEN1 mutation showed, however, reduced load of glycogen. Finally, we demonstrate the presence of α‐amylase within synapses of isolated primary neurons and show that inhibition of α‐amylase activity with Tendamistat alters neuronal activity measured by calcium imaging. In view of these findings, we hypothesize that α‐amylase has a glycogen degrading function within synapses, potentially important in memory formation. Hence, a loss of α‐amylase, which can be induced by Aβ pathology, may in part underlie the disrupted memory formation seen in AD patients.     

Adiponectin up‐regulates the decrease of myocardial autophagic flux induced by β1‐adrenergic receptor autoantibody partly dependent on AMPK

Cardiomyocytes autophagy is essential for maintaining cardiac function. Our previous studies have found that β₁‐adrenergic receptor autoantibody (β₁‐AA) induced the decreased myocardial autophagic flux, which resulted in cardiomyocyte death and cardiac dysfunction. And other studies demonstrated that β₁‐AA induced the decrease of AMPK phosphorylation, the key hub of autophagy pathway, while adiponectin up‐regulated autophagic flux mediated by AMPK. However, it is not clear whether adiponectin improves the inhibition of myocardial autophagic flux induced by β₁‐AA by up‐regulating the level of AMPK phosphorylation. In this study, it has been confirmed that β₁‐AA induced the decrease of AMPK phosphorylation level in both vivo and vitro. Moreover, pretreatment of cardiomyocytes with AMPK inhibitor Compound C could further reduce the autophagic flux induced by β₁‐AA. Adiponectin deficiency could aggravate the decrease of myocardial AMPK phosphorylation level, autophagic flux and cardiac function induced by β₁‐AA. Further, exogenous adiponectin could reverse the decline of AMPK phosphorylation level and autophagic flux induced by β₁‐AA and even reduce cardiomyocyte death. While pretreated with the Compound C, the adiponectin treatment did not improve the decreased autophagosome formation, but still improved the decreased autophagosome clearance induced by β₁‐AA in cardiomyocytes. This study is the first time to confirm that β₁‐AA could inhibit myocardial autophagic flux by down‐regulating AMPK phosphorylation level. Adiponectin could improve the inhibition of myocardial autophagic flux induced by β₁‐AA partly dependent on AMPK, so as to provide an experimental basis for the treatment of patients with β₁‐AA‐positive cardiac dysfunction.     

Asprin‐loaded strontium‐containing α‐calcium sulphate hemihydrate/nano‐hydroxyapatite composite promotes regeneration of critical bone defects

Our laboratory originally synthesized strontium(Sr)‐containing α‐calcium sulphate hemihydrate/nano‐hydroxyapatite composite (Sr‐α‐CSH/n‐HA) and demonstrated its ability to repair critical bone defects. This study attempted to incorporate aspirin into it to produce a better bone graft material for critical bone defects. After 5% Sr‐α‐CSH was prepared by coprecipitation and hydrothermal methods, it was mixed with aspirin solution of different concentrations (50 μg/ml, 200 μg/ml, 800 μg/ml and 3200 μg/ml) at a fixed liquid‐solid ratio (0.54 v/w) to obtain aspirin‐loaded Sr‐α‐CSH/n‐HA composite. In vitro experiments were performed on the composite extracts. The tibial defects (3 mm*5 mm) in SD rat model were filled with the composite for 4 weeks and 12 weeks to evaluate its osteogenic capacity in vivo. Our results showed its capability of proliferation, migration and osteogenesis of BMSCs in vitro got improved. In vivo treatment with 800 μg/ml aspirin–loaded Sr‐α‐CSH/n‐HA composite led to significantly more new bone formation in the defects compared with Sr‐α‐CSH/n‐HA composite and significantly promoted the expression of osteogenic‐related genes and inhibited osteoclast activity. In general, our research suggests that aspirin‐loaded Sr‐α‐CSH/n‐HA composite may have a greater capacity of repairing tibial defects in SD rats than simple Sr‐α‐CSH/n‐HA composite.     

A novel multikinase inhibitor SKLB‐YTH‐60 ameliorates inflammation and fibrosis in bleomycin‐induced lung fibrosis mouse models

ObjectivesIdiopathic pulmonary fibrosis (IPF) is marked by the excessive accumulation of extracellular matrix, which participates in a variety of chronic diseases or injuries and seriously threatens human health. Due to the side effects of clinical drugs, there is still a need to develop novel and less toxic drugs to treat pulmonary fibrosis.Materials and MethodsSKLB‐YTH‐60 was developed through computer‐aided drug design, de novo synthesis and high‐throughput screening. We employed the bleomycin (BLM)‐induced lung fibrosis animal models and used TGF‐β₁ to induce the epithelial‐mesenchymal transition (EMT) of A549 cells in vitro. Meanwhile, the protein expression of collagen I and the α‐smooth muscle actin (α‐SMA), E‐cadherin, p‐FGFR1, p‐PLCγ, p‐Smad2/3 and p‐Erk1/2 was detected by western blot.ResultsYTH‐60 has obvious anti‐proliferative activity on fibroblasts and A549 cells. Moreover, YTH‐60 could impair the EMT of A549 cells and suppressed fibrosis by inhibiting FGFR and TGF‐β/Smad‐dependent pathways. Intraperitoneal administration of preventive YTH‐60 could significantly reduce the degree of fibrosis in mice and regulate the imbalance of the immune microenvironment. In addition, we observed that therapeutic YTH‐60 treatment attenuated fibrotic changes in mice during the period of fibrosis. Importantly, YTH‐60 has shown an acceptable oral bioavailability (F = 17.86%) and appropriate eliminated half‐life time (T _1/2 = 8.03 hours).ConclusionsTaken together, these preclinical evaluations suggested that YTH‐60 could be a promising drug candidate for treating IPF.     

Fibronectin type III domain‐containing 5 improves aging‐related cardiac dysfunction in mice

Aging is an important risk factor for cardiovascular diseases, and aging‐related cardiac dysfunction serves as a major determinant of morbidity and mortality in elderly populations. Our previous study has identified fibronectin type III domain‐containing 5 (FNDC5) and its cleaved form, irisin, as the cardioprotectant against doxorubicin‐induced cardiomyopathy. Herein, aging or matched young mice were overexpressed with FNDC5 by adeno‐associated virus serotype 9 (AAV9) vectors, or subcutaneously infused with irisin to uncover the role of FNDC5 in aging‐related cardiac dysfunction. To verify the involvement of nucleotide‐binding oligomerization domain‐like receptor with a pyrin domain 3 (NLRP3) and AMP‐activated protein kinase α (AMPKα), Nlrp3 or Ampkα2 global knockout mice were used. Besides, young mice were injected with AAV9‐FNDC5 and maintained for 12 months to determine the preventive effect of FNDC5. Moreover, neonatal rat cardiomyocytes were stimulated with tumor necrosis factor‐α (TNF‐α) to examine the role of FNDC5 in vitro. We found that FNDC5 was downregulated in aging hearts. Cardiac‐specific overexpression of FNDC5 or irisin infusion significantly suppressed NLRP3 inflammasome and cardiac inflammation, thereby attenuating aging‐related cardiac remodeling and dysfunction. In addition, irisin treatment also inhibited cellular senescence in TNF‐α‐stimulated cardiomyocytes in vitro. Mechanistically, FNDC5 activated AMPKα through blocking the lysosomal degradation of glucagon‐like peptide‐1 receptor. More importantly, FNDC5 gene transfer in early life could delay the onset of cardiac dysfunction during aging process. We prove that FNDC5 improves aging‐related cardiac dysfunction by activating AMPKα, and it might be a promising therapeutic target to support cardiovascular health in elderly populations.     

SIRT2‐knockdown rescues GARS‐induced Charcot‐Marie‐Tooth neuropathy

Charcot‐Marie‐Tooth disease is the most common inherited peripheral neuropathy. Dominant mutations in the glycyl‐tRNA synthetase (GARS) gene cause peripheral nerve degeneration and lead to CMT disease type 2D. The underlying mechanisms of mutations in GARS (GARS^CMT2D) in disease pathogenesis are not fully understood. In this study, we report that wild‐type GARS binds the NAD⁺‐dependent deacetylase SIRT2 and inhibits its deacetylation activity, resulting in the acetylated α‐tubulin, the major substrate of SIRT2. The catalytic domain of GARS tightly interacts with SIRT2, which is the most CMT2D mutation localization. However, CMT2D mutations in GARS cannot inhibit SIRT2 deacetylation, which leads to a decrease of acetylated α‐tubulin. Genetic reduction of SIRT2 in the Drosophila model rescues the GARS‐induced axonal CMT neuropathy and extends the life span. Our findings demonstrate the pathogenic role of SIRT2‐dependent α‐tubulin deacetylation in mutant GARS‐induced neuropathies and provide new perspectives for targeting SIRT2 as a potential therapy against hereditary axonopathies.     

Identifying the patterns of changes in α‐ and β‐diversity across Dacrydium pectinatum communities in Hainan Island,China

Exploring vegetation distribution spatial patterns facilitates understanding how biodiversity addresses the potential threat of future climate variability, especially for highly diverse and threatened tropical plant communities, but few empirical studies have been performed. Dacrydium pectinatum is a constructive and endangered species in the tropical mountain forests of Hainan Island, China. In this study, sixty‐eight 30 m × 30 m permanent plots of D. pectinatum were investigated, and species‐based and phylogenetic‐based methods were used to analyze the α‐ and β‐diversity pattern variation and its key drivers. Our study showed that species and phylogenetic α‐diversity patterns are different on a local scale. However, on a regional scale, the variations in the two α‐diversity patterns tend to converge, and they decrease with increasing elevation. The phylogenetic structure changes from overdispersion to convergence with increasing elevation. Soil (SOM, TP, AP), topography (EL, SL), and stand (CD) factors and α‐diversity showed close correlations. Species and phylogenetic β‐diversity have significant positive correlations with changing environmental distance and geographical distance; however, as a representative form of habitat heterogeneity, elevation distance has a greater impact on β‐diversity changes than geographical distance. In conclusion, the α‐ and β‐diversity patterns of the D. pectinatum community are mainly related to habitat filtering, especially in high‐elevation areas, and the colonization history of various regions also affects the formation of diversity patterns. Species‐based and phylogenetic‐based methods robustly demonstrated the key role of the habitat filtering hypothesis in community assembly. We believe that more plant diversity patterns need to be explored to understand the biodiversity formation mechanisms in tropical forests. We also recommend strengthening the construction and management of nature reserves to help address the biodiversity loss crisis in endangered tropical plant communities.     

The stiffness‐controlled release of interleukin‐6 by cardiac fibroblasts is dependent on integrin α2β1

Cardiac fibroblasts are able to sense the rigidity of their environment. The present study examines whether the stiffness of the substrate in cardiac fibroblast culture can influence the release of interleukin‐6 (IL‐6), interleukin‐11 (IL‐11) and soluble receptor of IL‐6 (sIL‐6R). It also examines the roles of integrin α2β1 activation and intracellular signalling in these processes. Cardiac fibroblasts were cultured on polyacrylamide gels and grafted to collagen, with an elasticity of E = 2.23 ± 0.8 kPa (soft gel) and E = 8.28 ± 1.06 kPa (stiff gel, measured by Atomic Force Microscope). Flow cytometry and ELISA demonstrated that the fibroblasts cultured on the soft gel demonstrated higher expression of the α2 integrin subunit and increased α2β1 integrin count and released higher levels of IL‐6 and sIL‐6R than those on the stiff gel. Substrate elasticity did not modify fibroblast IL‐11 content. The silencing of the α2 integrin subunit decreased the release of IL‐6. Similar effects were induced by TC‐I 15 (an α2β1 integrin inhibitor). The IL‐6 levels in the serum and heart were markedly lower in α2 integrin‐deficient mice B6.Cg‐Itga2^{tm1.1Tkun/tm1.1Tkun} than wild type. Inhibition of Src kinase by AZM 475271 modifies the IL‐6 level. sIL‐6R secretion is not dependent on α2β1 integrin. Conclusion: The elastic properties of the substrate influence the release of IL‐6 by cardiac fibroblasts, and this effect is dependent on α2β1 integrin and kinase Src activation.     

Correlated alternative side chain conformations in the RNA-recognition motif of heterogeneous nuclear ribonucleoprotein A1

The RNA-recognition motif (RRM) is a common and evolutionarily conserved RNA-binding module. Crystallographic and solution structural studies have shown that RRMs adopt a compact α/β structure, in which four antiparallel β-strands form the major RNA-binding surface. Conserved aromatic residues in the RRM are located on the surface of the β-sheet and are important for RNA binding. To further our understanding of the structural basis of RRM-nucleic acid interaction, we carried out a high resolution analysis of UP1, the N-terminal, two-RRM domain of heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1), whose structure was previously solved at 1.75–1.9 Å resolution. The two RRMs of hnRNP A1 are closely related but have distinct functions in regulating alternative pre-mRNA splice site selection. Our present 1.1 Å resolution crystal structure reveals that two conserved solvent-exposed phenylalanines in the first RRM have alternative side chain conformations. These conformations are spatially correlated, as the individual amino acids cannot adopt each of the observed conformations independently. These phenylalanines are critical for nucleic acid binding and the observed alternative side chain conformations may serve as a mechanism for regulating nucleic acid binding by RRM-containing proteins.     

Purification and characterization of the receptor‐binding domain of SARS‐CoV‐2 spike protein from Escherichia coli

SARS‐CoV‐2 is responsible for a disruptive worldwide viral pandemic, and renders a severe respiratory disease known as COVID‐19. Spike protein of SARS‐CoV‐2 mediates viral entry into host cells by binding ACE2 through the receptor‐binding domain (RBD). RBD is an important target for development of virus inhibitors, neutralizing antibodies, and vaccines. RBD expressed in mammalian cells suffers from low expression yield and high cost. E. coli is a popular host for protein expression, which has the advantage of easy scalability with low cost. However, RBD expressed by E. coli (RBD‐1) lacks the glycosylation, and its antigenic epitopes may not be sufficiently exposed. In the present study, RBD‐1 was expressed by E. coli and purified by a Ni Sepharose Fast Flow column. RBD‐1 was structurally characterized and compared with RBD expressed by the HEK293 cells (RBD‐2). The secondary structure and tertiary structure of RBD‐1 were largely maintained without glycosylation. In particular, the major β‐sheet content of RBD‐1 was almost unaltered. RBD‐1 could strongly bind ACE2 with a dissociation constant (K_D) of 2.98 × 10^–8 M. Thus, RBD‐1 was expected to apply in the vaccine development, screening drugs and virus test kit.     

Temporal and brain region‐specific elevations of soluble Amyloid‐β40‐42 in the Ts65Dn mouse model of Down syndrome and Alzheimer’s disease

Down syndrome (DS) is a leading cause of intellectual disability that also results in hallmark Alzheimer''s disease (AD) pathologies such as amyloid beta (Aβ) plaques and hyperphosphorylated tau. The Ts65Dn mouse model is commonly used to study DS, as trisomic Ts65Dn mice carry 2/3 of the triplicated gene homologues as occur in human DS. The Ts65Dn strain also allows investigation of mechanisms common to DS and AD pathology, with many of these triplicated genes implicated in AD; for example, trisomic Ts65Dn mice overproduce amyloid precursor protein (APP), which is then processed into soluble Aβ_40‐42 fragments. Notably, Ts65Dn mice show alterations to the basal forebrain, which parallels the loss of function in this region observed in DS and AD patients early on in disease progression. However, a complete picture of soluble Aβ_40‐42 accumulation in a region‐, age‐, and sex‐specific manner has not yet been characterized in the Ts65Dn model. Here, we show that trisomic mice accumulate soluble Aβ_40‐42 in the basal forebrain, frontal cortex, hippocampus, and cerebellum in an age‐specific manner, with elevation in the frontal cortex and hippocampus as early as 4 months of age. Furthermore, we detected sex differences in accumulation of Aβ_40‐42 within the basal forebrain, with females having significantly higher Aβ_40‐42 at 7–8 months of age. Lastly, we show that APP expression in the basal forebrain and hippocampus inversely correlates with Aβ_40‐42 levels. This spatial and temporal characterization of soluble Aβ_40‐42 in the Ts65Dn model allows for further exploration of the role soluble Aβ plays in the progression of other AD‐like pathologies in these key brain regions.     

IFN‐γ+IL‐17+Th17 cells regulate fibrosis through secreting IL‐21 in systemic scleroderma

This study aimed to explore the function of IFN‐γ⁺IL‐17⁺Th17 cells on fibrosis in systemic scleroderma (SSc). Blood and skin samples were collected from 20 SSc cases and 10 healthy individuals. The percentage of IFN‐γ⁺IL‐17⁺Th17 cells was detected using flow cytometry. The in vitro induction of IFN‐γ⁺IL‐17⁺Th17 cells was performed adopting PHA and rIL‐12. Gene expression was detected via quantitative real‐time polymerase chain reaction (qRT‐PCR), whereas western blot analysis was adopted for protein analysis. The distribution of IFN‐γ⁺IL‐17⁺Th17 cells was significantly increased in SSc cases and positively correlated with SSc stages (P = .031), disease duration (P = .016), activity (P = .025) and skin scores (P < .001). In vitro, IFN‐γ⁺IL‐17⁺Th17 cells could promote the expressions of α‐SMA and COL1A1, revealing increased fibroblasts’ proliferation and enhanced collagen‐secreting capacity. In addition, IL‐21 expression was significantly increased in co‐culture medium of IFN‐γ⁺IL‐17⁺Th17 cells and fibroblasts (P < .001). IL‐21 neutralizer treatment resulted in the down‐regulation of α‐SMA and COL1A1. IL‐21 was confirmed as an effector of IFN‐γ⁺IL‐17⁺Th17 cells in fibrosis process. The distribution of IFN‐γ⁺IL‐17⁺Th17 cells was significantly increased in SSc cases and positively correlated with disease activity. IFN‐γ⁺IL‐17⁺Th17 cells could promote fibroblast proliferation and enhance collagen‐secreting ability via producing IL‐21, thus contributing to fibrosis in SSc.     

Inhibition of PKC‐δ reduce rhabdomyolysis‐induced acute kidney injury

Despite extensive research, the mechanisms underlying rhabdomyolysis‐induced acute kidney injury (AKI) remain largely elusive. In this study, we established both cell and murine models of rhabdomyolysis‐induced AKI by using myoglobin and glycerin, respectively, and provided evidence that protein kinase Cδ (PKC‐δ) was activated in both models and subsequently promoted cell apoptosis. Moreover, we found that this detrimental effect of PKC‐δ activation can be reversed by its pharmaceutical inhibitor rottlerin. Furthermore, we detected and confirmed the existence of PKC‐δ‐mediated myoglobin‐induced cell apoptosis and the expression of TNF‐α and IL1‐β via regulation of the p38MAPK and ERK1/2 signalling pathways. In summary, our research revealed the role of PKC‐δ in renal cell apoptosis and suggests that PKC‐δ is a viable therapeutic target for rhabdomyolysis‐induced AKI.