Effects of cold acclimation on serum biochemical parameters and metabolite profiles in Schizothorax prenanti.

BACKGROUND: Environmental temperature is critical in regulating biological functions in fish. S. prenanti is a kind of cold-water fish, but of which we have little knowledge about the metabolic adaptation and physiological responses to long-term cold acclimation. RESULTS: In this study, we determined the physiological responses of S. prenanti serum after 30 days of exposure to 6℃. Compared with the control group, the levels of TC, TG, and LDL-C in the serum were significantly (P < 0.05) increased, and the level of glucose was significantly (P < 0.05) decreased under cold acclimation. Cold acclimation had no effect on the gene expression of pro-inflammatory factors and anti-inflammatory factors of S. prenanti. Metabolomics analysis by LC-MS showed that a total of 60 differential expressed metabolites were identified after cold acclimation, which involved in biosynthesis of amino acids, biosynthesis of unsaturated fatty acids, steroid degradation, purine metabolism, and citrate cycle pathways. CONCLUSION: The results indicate that cold acclimation can alter serum metabolites and metabolic pathways to alter energy metabolism and provide insights for the physiological regulation of cold-water fish in response to cold acclimation.

Mid1 promotes synovitis in rheumatoid arthritis via ubiquitin-dependent post-translational modification.

INTRODUCTION: Current anti-rheumatic drugs are primarily modulating immune cell activation, yet their effectiveness remained suboptimal. Therefore, novel therapeutics targeting alternative mechanisms, such as synovial activation, is urgently needed. OBJECTIVES: To explore the role of Midline-1 (Mid1) in synovial activation. METHODS: NOD.Cg-Prkdcscid Il2rgtm1Wjl/SzJ (NSG) mice were used to establish a subcutaneous xenograft model. Wild-type C57BL/6, Mid1-/-, Dpp4-/-, and Mid1-/-Dpp4-/- mice were used to establish a collagen-induced arthritis model. Cell viability, cell cycle, qPCR and western blotting analysis were used to detect MH7A proliferation, dipeptidyl peptidase-4 (DPP4) and Mid1 levels. Co-immunoprecipitation and proteomic analysis identified the candidate protein of Mid1 substrates. Ubiquitination assays were used to determine DPP4 ubiquitination status. RESULTS: An increase in Mid1, an E3 ubiquitin ligase, was observed in human RA synovial tissue by GEO dataset analysis, and this elevation was confirmed in a collagen-induced mouse arthritis model. Notably, deletion of Mid1 in a collagen-induced arthritis model completely protected mice from developing arthritis. Subsequent overexpression and knockdown experiments on MH7A, a human synoviocyte cell line, unveiled a previously unrecognized role of Mid1 in synoviocyte proliferation and migration, the key aspects of synovial activation. Co-immunoprecipitation and proteomic analysis identified DPP4 as the most significant candidate of Mid1 substrates. Mechanistically, Mid1 promoted synoviocyte proliferation and migration by inducing ubiquitin-mediated proteasomal degradation of DPP4. DPP4 deficiency led to increased proliferation, migration, and inflammatory cytokine production in MH7A, while reconstitution of DPP4 significantly abolished Mid1-induced augmentation of cell proliferation and activation. Additionally, double knockout model showed that DPP4 deficiency abolished the protective effect of Mid1 defect on arthritis. CONCLUSION: Overall, our findings suggest that the ubiquitination of DPP4 by Mid1 promotes synovial cell proliferation and invasion, exacerbating synovitis in RA. These results reveal a novel mechanism that controls synovial activation, positioning Mid1 as a promising target for therapeutic intervention in RA.

High level of C3 is associated with Th2 immune response and liver fibrosis in patients with schistosomiasis.

Long-term infection of schistosomiasis will seriously affect the liver health of patients. The serum of 334 chronic Schistosoma japonicum patients and 149 healthy volunteers was collected. Compared with heathy people, the level of C4 (complement 4) was increased, and the level of C3 (complement 3) was in an obvious skewed distribution. ELISA was performed to detect the serum cytokines, the results showed that the levels of IFN-γ (interferon-γ), IL (interleukin)-2 and TNF-α (tumour necrosis factor-α) were reduced, while the levels of Th2 cytokines (IL-4, IL-6 and IL-10) were increased. In the serum of patients with high C3, the secretion of HA (hyaluronic acid), LN (laminin), IV-C (type IV collagen) and PCIII (type III procollagen) were increased, the activation of hepatic stellate cells was promoted. Exogenous human recombinant C3 made mice liver structure of the mice damaged and collagen deposition. IFN-γ and IFN-γ/IL-4 were decreased, while HA, LN, PCIII and IV-C were increased, and the expressions of α-SMA and TGF-ß1 in liver tissues were up-regulated. However, the addition of IFN-γ partially reversed the effect of C3 on promoting fibrosis. High level of C3 is associated with Th2 immune response and liver fibrosis in patients with schistosomiasis.

Ferroptosis: a potential target for the treatment of atherosclerosis.

Atherosclerosis (AS), the main contributor to acute cardiovascular events, such as myocardial infarction and ischemic stroke, is characterized by necrotic core formation and plaque instability induced by cell death. The mechanisms of cell death in AS have recently been identified and elucidated. Ferroptosis, a novel iron-dependent form of cell death, has been proven to participate in atherosclerotic progression by increasing endothelial reactive oxygen species (ROS) levels and lipid peroxidation. Furthermore, accumulated intracellular iron activates various signaling pathways or risk factors for AS, such as abnormal lipid metabolism, oxidative stress, and inflammation, which can eventually lead to the disordered function of macrophages, vascular smooth muscle cells, and vascular endothelial cells. However, the molecular pathways through which ferroptosis affects AS development and progression are not entirely understood. This review systematically summarizes the interactions between AS and ferroptosis and provides a feasible approach for inhibiting AS progression from the perspective of ferroptosis.

Targeting hypoxia-inducible factor-1, for cancer treatment: Recent advances in developing small-molecule inhibitors from natural compounds.

Rapid progress in molecular cancer biology coupled with the discovery of novel oncology drugs has opened new horizons for cancer target discovery. As one of the crucial signaling pathways related to tumorigenesis, hypoxia-inducible factor-1 (HIF-1) coordinates the activity of many transcription factors and their downstream molecules that impact tumor growth and metastasis. Accumulating evidence suggests that the transcriptional responses to acute hypoxia are mainly attributable to HIF-1α. Moreover, the overexpression of HIF-1α in several solid cancers has been found to be strongly associated with poor prognosis. Thus, pharmacological targeting of the HIF-1 signaling pathways has been considered as a new strategy for cancer therapy in the recent years. Although over the past decade, tremendous efforts have been made in preclinical studies to develop new HIF-1 inhibitors from natural products (reservoirs of novel therapeutic agents), to date, these efforts have not been successfully translated into clinically available treatments. In this review, we provide new insights into the bio-pharmacological considerations for selecting natural compounds as potential HIF-1 inhibitors to accelerate anti-cancer drug development. In addition, we highlighted the importance of assessing the dependency of cancer on HIF1A to shortlist cancer types as suitable disease models. This may subsequently lead to new paradigms for discovering more HIF-1 inhibitors derived from natural products and facilitate the development of potent therapeutic agents targeting specific cancer types.

Transcriptome analysis reveals the high temperature induced damage is a significant factor affecting the osmotic function of gill tissue in Siberian sturgeon (Acipenser baerii).

BACKGROUND: Maintaining osmotic equilibrium plays an important role in the survival of cold-water fishes. Heat stress has been proven to reduce the activity of Na+/K+-ATPase in the gill tissue, leading to destruction of the osmotic equilibrium. However, the mechanism of megatemperature affecting gill osmoregulation has not been fully elucidated. RESULTS: In this study, Siberian sturgeon (Acipenser baerii) was used to analyze histopathological change, plasma ion level, and transcriptome of gill tissue subjected to 20℃, 24℃and 28℃. The results showed that ROS level and damage were increased in gill tissue with the increasing of heat stress temperature. Plasma Cl- level at 28℃ was distinctly lower than that at 20℃ and 24℃, while no significant difference was found in Na+ and K+ ion levels among different groups. Transcriptome analysis displayed that osmoregulation-, DNA-repair- and apoptosis-related terms or pathways were enriched in GO and KEGG analysis. Moreover, 194 osmoregulation-related genes were identified. Amongst, the expression of genes limiting ion outflow, occluding (OCLN), and ion absorption, solute carrier family 4, member 2 (AE2) solute carrier family 9, member 3 (NHE3) chloride channel 2 (CLC-2) were increased, while Na+/K+-ATPase alpha (NKA-a) expression was decreased after heat stress. CONCLUSIONS: This study reveals for the first time that the effect of heat stress on damage and osmotic regulation in gill tissue of cold-water fishes. Heat stress increases the permeability of fish's gill tissue, and induces the gill tissue to keep ion balance through active ion absorption and passive ion outflow. Our study will contribute to research of global-warming-caused effects on cold-water fishes.

HNRNPA2B1-mediated m6A modification of lncRNA MEG3 facilitates tumorigenesis and metastasis of non-small cell lung cancer by regulating miR-21-5p/PTEN axis.

BACKGROUND: Accumulating data indicate that N6-methyladenosine (m6A) RNA methylation and lncRNA deregulation act crucial roles in cancer progression. Heterogeneous nuclear ribonucleoprotein A2B1 (HNRNPA2B1) as an m6A "reader" has been reported to be an oncogene in multiple malignancies. We herein aimed to elucidate the role and underlying mechanism by which HNRNPA2B1-mediated m6A modification of lncRNAs contributes to non-small cell lung cancer (NSCLC). METHODS: The expression levels of HNRNPA2B1 and their association with the clinicopathological characteristics and prognosis in NSCLC were determined by RT-qPCR, Western blot, immunohistochemistry and TCGA dataset. Then, the role of HNRNPA2B1 in NSCLC cells was assessed by in vitro functional experiments and in vivo tumorigenesis and lung metastasis models. HNRNPA2B1-mediated m6A modification of lncRNAs was screened by m6A-lncRNA epi-transcriptomic microarray and verified by methylated RNA immunoprecipitation (Me-RIP). The lncRNA MEG3-specific binding with miR-21-5p was evaluated by luciferase gene report and RIP assays. The effects of HNRNPA2B1 and (or) lncRNA MEG3 on miR-21-5p/PTEN/PI3K/AKT signaling were examined by RT-qPCR and Western blot analyses. RESULTS: We found that upregulation of HNRNPA2B1 was associated with distant metastasis and poor survival, representing an independent prognostic factor in patients with NSCLC. Knockdown of HNRNPA2B1 impaired cell proliferation and metastasis in vitro and in vivo, whereas ectopic expression of HNRNPA2B1 possessed the opposite effects. Mechanical investigations revealed that lncRNA MEG3 was an m6A target of HNRNPA2B1 and inhibition of HNRNPA2B1 decreased MEG3 m6A levels but increased its mRNA levels. Furthermore, lncRNA MEG3 could act as a sponge of miR-21-5p to upregulate PTEN and inactivate PI3K/AKT signaling, leading to the suppression of cell proliferation and invasion. Low expression of lncRNA MEG3 or elevated expression of miR-21-5p indicated poor survival in patients with NSCLC. CONCLUSIONS: Our findings uncover that HNRNPA2B1-mediated m6A modification of lncRNA MEG3 promotes tumorigenesis and metastasis of NSCLC cells by regulating miR-21-5p/PTEN axis and may provide a therapeutic target for NSCLC.

Biochemical, transcriptomic and metabolomic responses to total dissolved gas supersaturation and their underlying molecular mechanisms in Yangtze sturgeon (Acipenser dabryanus).

With the rapid development of hydropower facility construction, the total dissolved gas (TDG) generated by dam discharge is seriously threatening the survival of fish and has become an ecological environmental issue of global concern. However, how TDG affects fish physiology and the underlying molecular mechanism remain poorly known. In this study, Acipenser dabryanus, an ancient living fossil that is a flagship species of the Yangtze River, was exposed to water supersaturated with TDG at a level of 116% for 48 h. A comprehensive analysis was performed to study the effect of TDG supersaturation stress on A. dabryanus, including histopathological, biochemical, transcriptomic and metabolomic analyses. The histopathological results showed that mucosal-associated lymphoid tissues were seriously damaged after TDG supersaturation stress. Plasma catalase levels increased significantly under TDG supersaturation stress, while superoxide dismutase levels decreased significantly. Transcriptomic analysis revealed 289 upregulated genes and 162 downregulated genes in gill tissue and 535 upregulated and 104 downregulated genes in liver tissue. Metabolomic analysis revealed 63 and 164 differentially abundant metabolites between the control group and TDG group in gill and liver, respectively. The majority of heat shock proteins and genes related to ubiquitin and various immune-related pathways were significantly upregulated by TDG supersaturation stress. Integrated transcriptomic and metabolomic analyses revealed the upregulation of amino acid metabolism and glycometabolism pathways under TDG supersaturation stress. Glycerophospholipid metabolism was increased which might be associated with maintaining cell membrane integrity. This is the first study revealing the underlying molecular mechanisms of effects of TDG supersaturation on fish. Our results suggested that acute TDG supersaturation stress could enhance immune and antioxidative functions and activate energy metabolic pathways as an adaptive mechanism in A. dabryanus.

Transaldolase inhibits CD36 expression by modulating glutathione-p38 signaling, exerting protective effects against macrophage foam cell formation.

In atherosclerosis, macrophage-derived foam cell formation is considered to be a hallmark of the pathological process; this occurs via the uptake of modified lipoproteins. In the present study, we aim to determine the role of transaldolase in foam cell formation and atherogenesis and reveal the mechanisms underlying its role. Bone marrow-derived macrophages (BMDMs) isolated from mice successfully form foam cells after treatment with oxidized low-density lipoprotein (80 µg/mL). Elevated transaldolase levels in the foam cell model are assessed by quantitative polymerase chain reaction and western blot analysis. Transaldolase overexpression and knockdown in BMDMs are achieved via plasmid transfection and small interfering RNA technology, respectively. We find that transaldolase overexpression effectively attenuates, whereas transaldolase knockdown accelerates, macrophage-derived foam cell formation through the inhibition or activation of cholesterol uptake mediated by the scavenger receptor cluster of differentiation 36 (CD36) in a p38 mitogen-activated protein kinase (MAPK) signaling-dependent manner. Transaldolase-mediated glutathione (GSH) homeostasis is identified as the upstream regulator of p38 MAPK-mediated CD36-dependent cholesterol uptake in BMDMs. Transaldolase upregulates GSH production, thereby suppressing p38 activity and reducing the CD36 level, ultimately preventing foam cell formation and atherosclerosis. Thus, our findings indicate that the transaldolase-GSH-p38-CD36 axis may represent a promising therapeutic target for atherosclerosis.

Multifaceted role of ferroptosis in cardiovascular disease.

Ferroptosis is a newly identified form of non-apoptotic cell death characterised primarily by iron-dependent lipid peroxidation. It differs morphologically, biochemically, and genetically from other forms of cell death, such as apoptosis, autophagy, and necrosis. Although the molecular mechanism underlying ferroptosis remains unclear, multiple biological processes, such as iron metabolism, lipid peroxides, and systems, such as the glutathione system and the tetrahydrobiopterin/coenzyme Q10 system, appear to be involved. While the contribution of ferroptotic mechanisms to human diseases is not clear, recent studies have identified a number of ferroptosis-related genes. Cardiovascular diseases are the main cause of death globally. In this review, we outline the progress regarding the emerging role of ferroptosis in the pathogenesis of cardiac pathophysiological conditions and the association of ferroptosis with cardiomyopathy, myocardial ischemia-reperfusion injury, heart failure, and atherosclerosis. We further summarise newly discovered ferroptotic targets for the development of therapies for cardiovascular diseases. Finally, we discuss the current challenges and future research directions in cardiovascular disease treatments.

Impact of bone-implant gap size on the interfacial osseointegration: an in vivo study.

BACKGROUND: The bone-implant gap resulted from morphological mismatch between cervical bony endplates and implant footprint may have adverse impact on bone-implant interfacial osseointegration of cervical disc arthroplasty (CDA). The purpose of the study was to evaluate the impact of bone-implant gap size on the interfacial osseointegration in a rabbit animal model. METHODS: A series of round-plate implants with different teeth depth (0.5 mm, 1.0 mm, 1.5 mm and 2.0 mm) was specifically designed. A total of 48 New Zealand white rabbits were randomly categorized into four groups by the implants they received (0.5 mm: group A, 1.0 mm: group B, 1.5 mm: group C, 2.0 mm: group D). At 4th and 12th week after surgery, animals were sacrificed. Micro-CT, acid fuchsin and methylene blue staining and hematoxylin and eosin (HE) staining were conducted. RESULTS: At 4th week and 12th week after surgery, both micro-CT and HE staining showed more new bone formation and larger bone coverage in group A and group B than that in group C and group D. At 12th week, the bone biometric parameters were significantly superior in group C when compared with group D (p < 0.05). At 12th week, hard tissue slicing demonstrated larger portion of direct contact of new bone to the HA coating in group A and group B. CONCLUSIONS: Bone-implant gap size larger than 1.0 mm negatively affected bone-implant osseointegration between compact bone and HA coated implant surface.

Integrated biochemical, transcriptomic and metabolomic analyses provide insight into heat stress response in Yangtze sturgeon (Acipenser dabryanus).

Temperature fluctuations caused by climate change and global warming pose a great threat to various species. Most fish are particularly vulnerable to elevated temperatures. Understanding the mechanism of high-temperature tolerance in fish can be beneficial for proposing effective strategies to help fish cope with global warming. In this study, we systematically studied the effects of high temperature on Acipenser dabryanus, an ancient living fossil and flagship species of the Yangtze River, at the histological, biochemical, transcriptomic and metabolomic levels. Intestinal and liver tissues from the control groups (18 °C) and acute heat stress groups (30 °C) of A. dabryanus were sampled for histological observation and liver tissues were assessed for transcriptomic and metabolomic profiling. Histopathological analysis showed that the intestine and liver tissues were damaged after heat stress. The plasma cortisol content and the levels of oxidative stress markers (catalase/glutathione reductase) and two aminotransferases (aspartate aminotransferase/alanine aminotransferase) increased significantly in response to acute heat stress. Transcriptomic and metabolomic methods showed 6707 upregulated and 4189 downregulated genes and 64 upregulated and 78 downregulated metabolites in the heat stress group. Heat shock protein (HSP) genes showed striking changes in expression under heat stress, with 21 genes belonging to the HSP30, HSP40, HSP60, HSP70 and HSP90 families significantly upregulated by short-term heat stress. The majority of genes associated with ubiquitin and various immune-related pathways were also markedly upregulated in the heat stress group. In addition, the combined analysis of metabolites and gene profiles suggested an enhancement of amino acid metabolism and glycometabolism and the suppression of fatty acid metabolism during heat stress, which could be a potential energy conservation strategy for A. dabryanus. To the best of our knowledge, the present study represents the first attempt to reveal the mechanisms of heat stress responses in A. dabryanus, which can provide insights into improved cultivation of fish in response to global warming.

Comprehensive analysis of full-length transcriptomes of Schizothorax prenanti by single-molecule long-read sequencing.

Schizothorax prenanti (S. prenanti) is one of the most important aquaculture species in the southwest of China. However, information of the full-length transcripts in S. prenanti remains unknown. In this study, single-molecule real-time (SMRT) sequencing was performed to generate full-length transcriptomes of S.prenanti. In total, 23.26 Gb of clean reads were generated. A total of 312,587 circular consensus sequences (CCS) were obtained with average lengths of 2634 bp and 84.16% (270,662) of CCS were full-length non-chimeric reads. After being corrected with Illumina library sequencing, 18,005 contigs were obtained, with 17,797 (98.81%) successfully annotated in eight public databases, including 15,839 complete open reading frames (ORFs) with an average length of 1330 bp. Furthermore, a total of 4152 alternative splicing (AS) events and 250 long non-coding RNA (lncRNA) transcripts were detected. Additionally, a total of 1129 putative transcription factors (TFs) members from 56 TF families and 11,660 simple sequence repeats (SSRs) were identified. This study provided a valuable resource of full-length transcripts for further research on S. prenanti.

Genetic variation of E6, E7, and L1 genes of human papillomavirus 51 from central China.

The incidence of cervical cancer is closely related to high-risk human papillomavirus (HR-HPV). Women in Jingzhou had relatively high susceptibility to HPV-51, whose ratio was 9.61% (456/4743) among HR-HPV-positive samples and ranked fifth in all analyzed HR-HPV types. In this study, variations and phylogenetic trees of HPV-51 E6-E7 and L1 sequences were analyzed by MEGA-X. The selective pressure was estimated using PAML. The B-cell epitope of L1 amino acid sequences and T-cell epitope of E6 and E7 amino acid sequences were further predicted by ABCpred server and IEDB website, respectively. In the E6-E7 sequences 14 single nucleotide variants occurred, among which 4 were nonsynonymous variants and 10 were synonymous variants. A total of 41 single nucleotide variants were identified in the L1 sequences, including 10 nonsynonymous variants and 31 synonymous variants. All the isolates of both E6-E7 and L1 were classified into the A variant lineage. In HPV-51 E6-E7 and L1 sequences, no positively selected site was found. Two nonconservative substitutions, H119Y and N176S in L1, affected multiple hypothetical B-cell epitopes. Three nonconservative substitutions, T86P, S100L in E6, and F29L in E7, affected multiple hypothetical T-cell epitopes. Elucidation of the HR-HPV prevalence characteristics and genetic variations of HPV-51 in central China may contribute to future investigations of diagnostic probes, therapeutic or preventative vaccines with wider coverage.

Genetic variability of E6 and E7 genes of human papillomavirus type 58 in Jingzhou, Hubei Province of central China.

BACKGROUND: Cervical cancer is a common malignant tumor in women, with a high mortality rate, has great harm to women's health. Long-term and persistent infection of high-risk human papillomavirus (HR-HPV) is the main reason of the occurrence and development of cervical cancer. METHODS: The infection rate of HPV-58 is higher in the Jingzhou area. In this study, 172 complete HPV-58 E6-E7 sequences were amplified by polymerase chain reaction (PCR), the amplified products were sequenced, and the gene variations of HPV-58 E6-E7 were analyzed. A Neighbor-Joining phylogenetic tree was constructed by MEGA 11. The secondary structure of E6 and E7 protein was investigated. PAML X was used to analyze the selective pressure. The B cell epitopes of E6 and E7 proteins in HPV-58 were predicted by ABCpred server. RESULTS: In E6 sequences, 10 single nucleotide variants were observed, including 7 synonymous and 3 non-synonymous variants. In E7 sequences, 12 single nucleotide variants were found, including 3 synonymous variants and 9 non-synonymous variants. There are 5 novel variants. The phylogenetic analysis showed that all the E6-E7 sequences were distributed in A lineage. No positively selected site was found in E6 sequence, but G63 in E7 sequences was identified as positively selected site. Some amino acid substitutions affected multiple B cell epitopes. CONCLUSION: Various E6 and E7 mutational data may prove useful for development of better diagnostic and vaccines for the region of Jingzhou, Hubei province of central China.

Comprehensive transcriptome analysis reveals the effect of feeding rhythm on the immunity and metabolism of Acipenser dabryanus.

Acipenser dabryanus is a species endemic to Yangtze River drainage in China and is listed as a critical endangered species on the IUCN Red List. In the present study, the liver and spleen transcriptomes were analyzed by comparing the data of A. dabryanus that experienced nine different feeding rhythms (once a day diurnal, T1; two times a day diurnal, T2; three times a day diurnal, T3; four times a day, T4; five times a day, T5; six times a day, T6; once a day nocturnal, Tn1; two times a day nocturnal, Tn2; and three times a day nocturnal, Tn3). Transcriptome sequencing generated 1,901,236,482 clean reads, encompassing 570.4 Gb of sequence data. The reads were assembled into 287,372 unigenes with an average length of 803 bp and an N50 of 1004 bp. KEGG analysis showed that 1,080, 1,030, and 1216 unigenes were annotated to lipid metabolism, amino acid metabolism and carbohydrate metabolism, respectively, and 2549 unigenes were annotated to the immune system category. Differentially expressed genes (DEGs) between different feeding frequency groups or between nighttime and daytime feeding were obtained and functionally enriched. Importantly, DEGs participating in nutrition metabolism and various immunoregulation pathways and their expression profiles in A. dabryanus were discussed. Interestingly, the majority of key genes related to lipid metabolism or in immunodependent gene families, such as antimicrobial peptides, Toll-like receptors, chemokines, NOD-like receptors, B cell receptors and the major histocompatibility complex, were all significantly upregulated in animals in the T6 group compared to the characteristics of animals in the T2 group that had a normal feeding frequency. In addition, light/dark rhythm also affected the immunity of A. dabryanus, and fish fed at night possessed an improved immune response than fish fed at daytime. Our study suggested that feeding six times a day is optimal for A. dabryanus juvenile growth as it enhances the organism's nutrition metabolism and immune function.

Age-dependent aggregation of α-synuclein in the nervous system of gut-brain axis is associated with caspase-1 activation.

α-Synuclein (α-Syn) plays a key role in the development of Parkinson' desease (PD). As aging is acknowledged to be the greatest risk factor for PD, here we investigated α-Syn expression in the ileum, thoracic spinal cord, and midbrain of young (1-month-old), middle-aged (6-, 12-month-old) to old (18-month-old) mice. We demonstrated that both the levels of α-Syn monomers, oligomers and ratios of oligomers to monomers were increased with aging in the ileum, thoracic spinal cord, and midbrain. Whereas, the expression of tyrosine hydroxylase (TH), the rate-limiting enzyme for dopamine synthesis, was decreased with aging in the midbrain. We failed to find corresponding α-Syn mRNA increase with aging. However, we found an increased expression of caspase-1 in the ileum, thoracic spinal cord, and midbrain. A specific caspase-1 inhibitor VX765 significantly reduced levels of both the α-Syn monomers and oligomers triggered by the rotenone in vitro. Taken together, the increase in α-Syn aggregation with aging might not occur first in the gut, but simultaneously in the nervous system of gut-brain axis. The mechanism of the age-dependent aggregation of α-Syn in nervous system is likely triggered by the aging-related caspase-1 activation.

Molecular characterization and tissue distribution of cholecystokinin and its receptor in Yangtze sturgeon (Acipenser dabryanus) and their response to different feeding conditions.

Yangtze sturgeon (Acipenser dabryanus) is a species endemic to Yangtze River drainage in China and is listed as a critically endangered species on the IUCN Red List. In the present study, cholecystokinin (CCK), one of the most important neuroregulatory digestive genes, and its receptor (CCKr) were identified from the full-length transcriptome analysis of A. dabryanus. The deduced amino acid sequences of CCK and CCKr from A. dabryanus showed structural features common to those in other vertebrates. Gene expression profile analysis showed that CCK and CCKr were universally expressed in different tissues, and both had the highest expression in the brain. Starvation and refeeding significantly regulated the expression levels of CCK and CCKr in the brain, suggesting that CCK and CCKr were involved in feed intake regulation in A. dabryanus as in mammals. In addition, the expression levels of CCK and CCKr under different feeding frequencies were studied. Compared with the control group (fed two times a day), the expression levels of CCK and CCKr in the intestine and brain did not change significantly in the other groups after 8 weeks of rearing, indicating that the feeding frequency might not influence the appetite of A. dabryanus. The present work provides a basis for further investigation into the regulation of feeding in A. dabryanus.

Molecular and functional characterization of the retinol-binding protein 4 (RBP4) in hepatocytes of Schizothorax prenanti in response to palmitic acid.

Retinol-binding protein 4 (RBP4) protein is a kind of adipokines synthesized and secreted by the liver, which has been verified to play important roles in liver metabolism and energy homeostasis. However, the effects of RBP4 on hepatic lipid accumulation are still elusive in fish. In the present study, we cloned and characterized the RBP4 gene in Schizothorax prenanti (S. prenanti). RBP4 gene was specifically expressed in the liver and abdominal adipose tissue. Palmitic acid (PA; 400 µM) can significantly increase lipid deposition in primary hepatocytes after 12 h of treatment. Furthermore, RBP4 knockdown can relieve the excessive lipid deposition and endoplasmic reticulum stress in the hepatocytes caused by PA. The inhibition of RBP4 abolished the ability of PA to induce the expression of genes involved in lipogenesis and endoplasmic reticulum stress. These results demonstrate that RBP4 inhibition attenuated PA-induced lipid deposition and endoplasmic reticulum stress in hepatocytes of S. prenanti. This study could contribute to improve the understanding of RBP4 functions in the PA-induced lipid deposition in hepatocytes of fish.

Genetic variation of E6 and E7 genes of human papillomavirus 52 from Central China.

Cervical cancer is the fourth most common malignant tumor in women worldwide and is closely related to human papillomavirus (HPV). Women have the highest susceptibility to HPV-52 type in Jingzhou, China. In this study, E6-E7 sequences of 183 HPV-52 positive samples were amplified by a polymerase chain reaction and sequenced. HPV-52 E6-E7 gene variations were analyzed. The phylogenetic tree was constructed using the Kimura 2-parameter method. The secondary structure of the protein was analyzed. The selective pressure to E6-E7 genes was estimated using PAML. In addition, the B cell epitopes of the E6-E7 sequences in HPV-52 were predicted by the ABCpred server. In E6 sequences, 15 single nucleotide variants were observed, including 6 nonsynonymous variants and 9 synonymous variants. In E7 sequences, 19 single nucleotide variants occurred, including 10 nonsynonymous variants and 9 synonymous variants. Six amino acid variants, including 3 nonconservative substitutions, were found in sequences encoding the alpha helix. Eight amino acid variants, including three nonconservative substitutions, occurred in sequences encoding the strand. Through phylogenetic analysis, the E6-E7 sequences were mainly distributed in B lineage. In HPV-52 E6-E7 sequences, no positively selected site was found. The nonconservative substitutions, such as K93R, K93E in E6, T37I, and D38N in E7, affected multiple hypothetical epitopes in the B cell. This study provides information for the investigation of HPV epidemic characters. The discovery of new variants of HPV-52 may lay the basis for the development of the virus diagnosis, further study of cervical cancer, and vaccine design in Central China.