The JAK-STAT pathway: from structural biology to cytokine engineering.

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway serves as a paradigm for signal transduction from the extracellular environment to the nucleus. It plays a pivotal role in physiological functions, such as hematopoiesis, immune balance, tissue homeostasis, and surveillance against tumors. Dysregulation of this pathway may lead to various disease conditions such as immune deficiencies, autoimmune diseases, hematologic disorders, and cancer. Due to its critical role in maintaining human health and involvement in disease, extensive studies have been conducted on this pathway, ranging from basic research to medical applications. Advances in the structural biology of this pathway have enabled us to gain insights into how the signaling cascade operates at the molecular level, laying the groundwork for therapeutic development targeting this pathway. Various strategies have been developed to restore its normal function, with promising therapeutic potential. Enhanced comprehension of these molecular mechanisms, combined with advances in protein engineering methodologies, has allowed us to engineer cytokines with tailored properties for targeted therapeutic applications, thereby enhancing their efficiency and safety. In this review, we outline the structural basis that governs key nodes in this pathway, offering a comprehensive overview of the signal transduction process. Furthermore, we explore recent advances in cytokine engineering for therapeutic development in this pathway.

Predicting anti-tumor efficacy of multi-functional nanomedicine on decellularized hepatocellular carcinoma-on-a-chip.

Traditional hepatocellular carcinoma-chip models lack the cell structure and microenvironments necessary for high pathophysiological correlation, leading to low accuracy in predicting drug efficacy and high production costs. This study proposed a decellularized hepatocellular carcinoma-on-a-chip model to screen anti-tumor nanomedicine. In this model, human hepatocellular carcinoma (HepG2) and human normal liver cells (L02) were co-cultured on a three-dimensional (3D) decellularized extracellular matrix (dECM) in vitro to mimic the tumor microenvironments of human hepatocellular carcinoma in vivo. Additionally, a smart nanomedicine was developed by encapsulating doxorubicin (DOX) into the ferric oxide (Fe3O4)-incorporated liposome nanovesicle (NLV/Fe+DOX). NLV/Fe+DOX selectively killed 78.59% ± 6.78% of HepG2 cells through targeted delivery and synergistic chemo-chemodynamic-photothermal therapies, while the viability of surrounding L02 cells on the chip model retained high, at over 90.0%. The drug efficacy tested using this unique chip model correlated well with the results of cellular and animal experiments. In summary, our proposed hepatocellular carcinoma-chip model is a low-cost yet accurate drug-testing platform with significant potential for drug screening.

Plin4 exacerbates cadmium-decreased testosterone level via inducing ferroptosis in testicular Leydig cells.

Strong evidence indicates that environmental stressors are the risk factors for male testosterone deficiency (TD). However, the mechanisms of environmental stress-induced TD remain unclear. Based on our all-cause male reproductive cohort, we found that serum ferrous iron (Fe2⁺) levels were elevated in TD donors. Then, we explored the role and mechanism of ferroptosis in environmental stress-reduced testosterone levels through in vivo and in vitro models. Data demonstrated that ferroptosis and lipid droplet deposition were observed in environmental stress-exposed testicular Leydig cells. Pretreatment with ferrostatin-1 (Fer-1), a specific ferroptosis inhibitor, markedly mitigated environmental stress-reduced testosterone levels. Through screening of core genes involved in lipid droplets formation, it was found that environmental stress significantly increased the levels of perilipins 4 (PLIN4) protein and mRNA in testicular Leydig cells. Further experiments showed that Plin4 siRNA reversed environmental stress-induced lipid droplet deposition and ferroptosis in Leydig cells. Additionally, environmental stress increased the levels of METTL3, METTL14, and total RNA m6A in testicular Leydig cells. Mechanistically, S-adenosylhomocysteine, an inhibitor of METTL3 and METTL14 heterodimer activity, restored the abnormal levels of Plin4, Fe2⁺ and testosterone in environmental stress-treated Leydig cells. Collectively, these results suggest that Plin4 exacerbates environmental stress-decreased testosterone level via inducing ferroptosis in testicular Leydig cells.

Transcriptional activation of SIRT5 by FOXA1 reprograms glycolysis to facilitate the malignant progression of diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most common diagnosed subtype of lymphoma with high invasiveness and heterogeneity. Glycolysis is involved in regulating DLBCL progression. We aimed to explore the role of forkhead box protein A1 (FOXA1) in DLBCL and the mechanisms related to sirtuine5 (SIRT5) and glycolysis. FOXA1 expression in DLBCL cells was analyzed. Then, the proliferation and apoptosis of DLBCL cells were detected using Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EDU) staining and flow cytometry analysis following FOXA1 or SIRT5 knockdown. The glycolysis was assessed by measuring extracellular acidification rate (ECAR), glucose consumption and lactate secretion. Immunoblotting was employed to examine the expression of apoptosis- and glycolysis-related proteins. Additionally, luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay were conducted to test the combination of FOXA1 to SIRT5 promotor region. Subsequently, SIRT5 expression was upregulated to conduct rescue assays. Finally, the effects of FOXA1 downregulation on the growth and glycolysis in OCI-ly7 tumor-bearing mice were examined. As a result, FOXA1 was upregulated in DLBCL cells and FOXA1 or SIRT5 knockdown inhibited the proliferation, accelerated the apoptosis and suppressed glycolysis reprograming in DLBCL cells. Importantly, FOXA1 could transcriptionally activate SIRT5 expression in DLBCL cells. Besides, SIRT5 overexpression counteracted the effects of FOXA1 deficiency on the proliferation, apoptosis and glycolysis reprogramming in DLBCL cells. Furthermore, FOXA1 knockdown inhibited the tumor growth, suppressed the glycolysis reprogramming and downregulated SIRT5 expression in vivo. In summary, FOXA1 could transcriptionally activate SIRT5 to reprogram glycolysis, thereby facilitating the malignant progression of DLBCL.

Clinical stratification of 1318 Primary Sjögren's Syndrome patients.

OBJECTIVE: Primary Sjögren's Syndrome (pSS) is a complex autoimmune disorder characterized by diverse clinical manifestations yet lacking effective therapeutic strategies currently. This study aims to gain a thorough understanding of the clinical landscape of pSS and further delineate its clinical subtypes, thereby enabling the efficient management for pSS. METHODS: We conducted a cross-sectional observational study of 1318 pSS patients. The pSS patients were categorized and compared based on gender, anti-SSA antibodies, and labial salivary gland biopsies (LGSB). Unsupervised clustering analysis was employed to identify pSS subtypes using systemic involvement among patients. Furthermore, we assessed clinical and biological variances among these subtypes. RESULTS: Through group comparisons, we observed more pronounced extraglandular manifestations among male patients, SSA-negative group, and those with positive LGSB results. Based on systemic involvement, pSS patients were categorized into four groups. C1 exhibited minimal systemic involvement, lacking hematologic or serologic manifestations, with the lowest ESSDAI scores. C2 presented with serologic changes in all patients, partial joint involvement, and no hematologic systemic manifestations. C3 lacked joint involvement but all members displayed hematologic systemic involvement, with higher rates of renal, cutaneous, and systemic manifestations. C4 encompassed patients with joint and hematologic involvement, displaying the highest ESSDAI scores. The positivity rates of antibodies, immunological parameters, and inflammatory markers exhibited significant differences among the groups. Furthermore, notable variances were observed in the expression of peripheral blood transcriptomic modules among these groups. CONCLUSION: In this cohort study, we summarized the clinical characteristics of Chinese patients with pSS and identified four distinct subgroups of pSS based on systemic involvement, revealing clinical and molecular disparities that unveil distinct pathobiological endotypes. Our findings hold significant implications for clinical management.

Enzyme-activated binary assembly for targeted, controlled delivery of anti-liver cancer compounds.

Liver cancer is the third leading cause of cancer deaths globally. The use of Hydroxycamptothecin (HCPT) as a first-line chemotherapeutic agent for liver, lung, and gastric cancers is often hampered by its low activity, limited targeting, and poor water solubility. This results in a low accumulation of HCPT in tumor cells, as well as the inability to maintain continuous treatment. Consequently, there is an urgent need to develop an accessory method that can enhance the therapeutic efficacy of HCPT while exhibiting good biocompatibility and targeted delivery ability. To address this critical issue, an enzyme-triggered supramolecular nanocarrier, refer as SCD/LCC SNCs, has been successfully developed, leveraging the aggregation of the negatively charged sulfate-modified ß-CDs and positively charged lauroylcholine chloride (LCC). This nanocarrier demonstrates acetylcholinesterase (LCC) triggered decomposition behavior, making it a promising drug carrier for HCPT. The cellular assays conducted have demonstrated that HCPT loaded into these SCD/LCC SNCs exhibit reduced cytotoxicity towards normal cells while maintaining robust tumor inhibitory activity and inducing apoptosis. Therefore, this study offers a promising strategy for the effective use of HCPT in the treatment of liver cancer.

Systematic review on the role of the gut microbiota in tumors and their treatment.

Tumors present a formidable health risk with limited curability and high mortality; existing treatments face challenges in addressing the unique tumor microenvironment (hypoxia, low pH, and high permeability), necessitating the development of new therapeutic approaches. Under certain circumstances, certain bacteria, especially anaerobes or parthenogenetic anaerobes, accumulate and proliferate in the tumor environment. This phenomenon activates a series of responses in the body that ultimately produce anti-tumor effects. These bacteria can target and colonize the tumor microenvironment, promoting responses aimed at targeting and fighting tumor cells. Understanding and exploiting such interactions holds promise for innovative therapeutic strategies, potentially augmenting existing treatments and contributing to the development of more effective and targeted approaches to fighting tumors. This paper reviews the tumor-promoting mechanisms and anti-tumor effects of the digestive tract microbiome and describes bacterial therapeutic strategies for tumors, including natural and engineered anti-tumor strategies.

Species recognition and the divergences in the chemical and ultrasonic signals between two coexisting Rattus species.

The ability to recognize and differentiate between conspecifics and heterospecifics as well as their signals is critical for the coexistence of closely related species. In the genus Rattus, species are morphologically similar and multiple species often coexist. Here, we investigated the interspecific recognition and signal differentiation of two sympatric rat species, the brown rat (Rattus norvegicus, RN) and the Asian house rat (Rattus tanezumi, RT). In a two-way choice test, both RN and RT females showed a preference for conspecific male rats to heterospecific ones. RT females showed a significant preference for accessible urine of males of same species to those of other species, but not for the inaccessible urine. On the other hand, there were significant differences in the structural characteristics of the ultrasonic vocalization emitted by males of these two rat species. Sodium dodecyl sulphate‒polyacrylamide gel electrophoresis (SDS‒PAGE) and isoelectric focusing electrophoresis unveiled that major urinary proteins (MUPs) in voided urine were more highly expressed in RN males versus RT males. The interspecific differences of urinary volatile compounds were also discussed. In conclusion, female rats had the ability to distinguish between males of either species.

First Report of Fusarium kyushuense Causing Leaf Spot on Sweet Persimmon in China.

Sweet persimmon (Diospyros kaki L.) is a fruit of significant nutritional and commercial value in Asia. In summer 2023, leaf spots were observed affecting 20 to 30% of sweet persimmon trees in a commercial orchard located in Gongcheng City, Guangxi, China. Initially, the infected leaves exhibited sparse light brown spots on their upper surface, which subsequently evolved into brown circular to irregular lesions encircled by a yellow halo. Eventually, these lesions became densely distributed across the leaves leading to insufficient nutrient accumulation in the fruit. To isolate the pathogen, diseased leaves were cut into small pieces (5×5 mm), disinfected with 75% ethanol for 15 seconds, followed by 1% NaClO for 1minute, rinsed three times with sterile water, and then transferred onto potato dextrose agar (PDA) plates. The plates were then incubated in darkness for 3 days at 25°C. Pure cultures were obtained using the hyphal-tip method and single-spore isolation. On PDA, the colonies initially appeared fluffy and white after 24 hours, turning yellowish or red after 3 days. Macroconidia (average length of 26.1 µm in length × 4.3 µm in width, n = 50) exhibited dorsiventral curvature and were hyaline, with 3 to 5 septa. Microconidia (average length of 9.45 µm in length × 3.4 µm in width, n = 50) were hyaline, aseptate, and oval. Two representative isolates, Gxfky1 and Gxfky2, were selected for further molecular analyses. Their internal transcribed spacer (ITS) region rDNA gene were amplified via PCR and sanger sequenced (GenBank Accession Nos. PP506475, PP506593) using the primer pair ITS1/ITS4 (White et al. 1990), showing more than 99% sequence identity with Fusarium kyushuense type-material strain NRRL3509 (NR_152943) according to BLASTn analysis in NCBI. To further confirm the identity of the isolates, four gene sequences were amplified: RPB1 (PP532864, PP532865), RPB2 (PP532866, PP532867), TEF1 (PP580505, PP580506), and TUB2 (PP532862, PP532863), using the F5/G2R, 5f2/11ar, EF1/EF2, and T1/T2 primer sets, respectively (O'Donnell et al., 1997; O'Donnell et al., 2010). A multi-locus maximum likelihood phylogenetic analysis revealed that Gxfky1 and Gxfky2 clustered with strains F. kyushuense with 100% bootstrap support. Pathogenicity tests using Gxfky1 and Gxfky2 were conducted on leaves of two-year-old sweet persimmon plants using non-wound inoculation. Specifically, 5-mm mycelial plugs and sterile agar plugs were placed on six leaves and secured with cling film, with six plugs each for the inoculation treatment and negative control, respectively. They were then incubated in a greenhouse at room temperature (25 ± 2°C) with a relative humidity of 70 to 80%. After 5 days, the same symptoms on naturally infected plants were observed on leaves inoculated with mycelium, while no symptoms were observed on the controls. The same fungus were reisolated from the inoculated leaves and identified based on morphology and the TEF1 gene sequence, thus fulfilling Koch's postulates. Fusarium kyushuense has previously been reported to cause diseases in various plant species, including maize (Cao et al., 2021), rice (Wang et al., 2024), and tobacco (Wang et al., 2013). To our knowledge, this is the first report of F. kyushuense causing leaf spot on sweet persimmon in China, which expands the known host range of this pathogen.

Cephalopod-Inspired Nanomaterials for Optical and Thermal Regulation: Mechanisms, Applications and Perspectives.

The manipulation of interactions between light and matter plays a crucial role in the evolution of organisms and a better life for humans. As a result of natural selection, precise light-regulatory systems of biology have been engineered that provide many powerful and promising bioinspired strategies. As the "king of disguise", cephalopods, which can perfectly control the propagation of light and thus achieve excellent surrounding-matching via their delicate skin structure, have made themselves an exciting source of inspiration for developing optical and thermal regulation nanomaterials. This review presents cutting-edge advancements in cephalopod-inspired optical and thermal regulation nanomaterials, highlighting the key milestones and breakthroughs achieved thus far. We begin with the underlying mechanisms of the adaptive color-changing ability of cephalopods, as well as their special hierarchical skin structure. Then, different types of bioinspired nanomaterials and devices are comprehensively summarized. Furthermore, some advanced and emerging applications of these nanomaterials and devices, including camouflage, thermal management, pixelation, medical health, sensing and wireless communication, are addressed. Finally, some remaining but significant challenges and potential directions for future work are discussed. We anticipate that this comprehensive review will promote the further development of cephalopod-inspired nanomaterials for optical and thermal regulation and trigger ideas for bioinspired design of nanomaterials in multidisciplinary applications.

Systemic contact dermatitis in a family: Case report.

BACKGROUND: Systemic contact dermatitis (SCD) is an allergic inflammatory skin disease. We report that 3 family members developed SCD after exposing to laundry detergent containing benzalkonium chloride, which is rare. SCD caused by benzalkonium chloride has been reported. However, Similar symptoms in the whole family caused by it have not been reported yet. In our case, a 36-year-old man was diagnosed as SCD, and his symptoms had not controlled after 7 days treatment, until he stopped dressing the clothes washed by the laundry detergent containing benzalkonium chloride. It was interesting that both his wife and the daughter developed SCD successively, and they have not exposed to any haptens besides the benzalkonium chloride in the laundry detergent. METHODS: Dermoscopic examination showed bright-red background, focal branching vessels and white scales. HE staining from the lesion revealed hyperkeratosis and parakeratosis, focal subcorneal microabscess, ocal hyperkeratosis, koilocyte in the epidermis, and erythrocyte extravasation, fibroplasia, hyaline degeneration and scattered aggregates of lymphocytes in the dermis. Then path test was performed 1 month after recovery with benzalkonium chloride 0.05% and 0.1% in petrolatum. RESULTS: Stop the laundry detergent containing benzalkonium chloride. The symptoms had controlled after they stopped the laundry detergent containing benzalkonium chloride. CONCLUSION: The case highlights that benzalkonium chloride with very low concentration and repeated exposure may be an active agent of SCD. It is of the utmost importance to pay close attention to patients presenting with similar symptoms within the family. A thorough examination of the medical history is essential to determine the underlying cause.

Suppressed testicular macrophage M1 polarization by HDAC5 enforces insensitivity to LPS-elicited blood-testis barrier damage.

Infertility caused by lipopolysaccharide (LPS) exposure due to infection is endangering male fertility worldwide, but the mechanism remains unclear. The blood-testis barrier (BTB) is essential for maintaining spermatogenesis and male fertility. In the present study, we showed that LPS (5.0 mg/kg) treatment markedly down-regulated the expression of BTB-related proteins, expanded the biotin penetration distance and caused histopathological injury in seminiferous tubules in mouse testes. Notably, testicular macrophage M1 polarization induced by LPS seems to be related to BTB damage, which was well confirmed by co-culture of RAW264.7 and TM4 cells in vitro. Interestingly, a low-dose LPS (0.1 mg/kg) pretreatment attenuated down-regulation of BTB-related proteins expression and histopathological injury and shorten biotin penetration distance in seminiferous tubules caused by LPS. Correspondingly, a low-dose LPS pretreatment suppresses testicular macrophage M1 polarization induced by LPS in mouse testes. Further experiments revealed that histone deacetylase 5 (HDAC5) was markedly down-regulated at 2 h and slightly down-regulated at 8 h, but up-regulated at 24 h in mouse testes after LPS treatment. Additionally, low-dose LPS pretreatment against the down-regulation of HDAC5 protein caused by LPS treatment. Notably, the suppressed testicular macrophage M1 polarization by low-dose LPS pretreatment was broken by BRD4354, a specific inhibitor of HDAC5 in vitro. These results suggest suppressed testicular macrophage M1 polarization by HDAC5 enforces insensitivity to LPS-elicited BTB damage.

Interface Engineering of VOx/Ni/Ni3N Heterostructures for Electrochemical Urea-Assisted Hydrogen Production.

Electrocatalytic hydrogen generation driven by renewable energy sources is severely limited by the slow oxygen evolution reaction (OER). Urea-assisted alkaline hydrogen production offers a perspective approach. However, the construction of efficient and robust anode catalysts is still challenging. Herein, an amorphous/crystalline VOx/Ni/Ni3N-heterostructured catalyst grown on carbon cloth was synthesized and used as a bifunctional electrocatalyst for the hydrogen evolution reaction (HER) and urea electrooxidation reaction (UOR). Benefiting from the electronic modification of intercomponents and abundant active sites, VOx/Ni/Ni3N exhibits an excellent electrochemical performance toward the HER and UOR. Theoretical calculations confirmed that the crystalline/amorphous VOx/Ni/Ni3N heterostructure has a suitable water dissociation energy and H* adsorption energy, thereby promoting the HER process. When the UOR and HER are integrated into an electrolytic device, VOx/Ni/Ni3N requires a potential of 1.40 V to achieve a current density of 10 mA cm-2.

Targeting PI3K family with small-molecule inhibitors in cancer therapy: current clinical status and future directions.

The Phosphatidylinositol-3-kinase (PI3K) family is well-known to comprise three classes of intracellular enzymes. Class I PI3Ks primarily function in signaling by responding to cell surface receptor stimulation, while class II and III are more involved in membrane transport. Under normal physiological conditions, the PI3K signaling network orchestrates cell growth, division, migration and survival. Aberrant activation of the PI3K signaling pathway disrupts cellular activity and metabolism, often marking the onset of cancer. Currently, the Food and Drug Administration (FDA) has approved the clinical use of five class I PI3K inhibitors. These small-molecule inhibitors, which exhibit varying selectivity for different class I PI3K family members, are primarily used in the treatment of breast cancer and hematologic malignancies. Therefore, the development of novel class I PI3K inhibitors has been a prominent research focus in the field of oncology, aiming to enhance potential therapeutic selectivity and effectiveness. In this review, we summarize the specific structures of PI3Ks and their functional roles in cancer progression. Additionally, we critically evaluate small molecule inhibitors that target class I PI3K, with a particular focus on their clinical applications in cancer treatment. Moreover, we aim to analyze therapeutic approaches for different types of cancers marked by aberrant PI3K activation and to identify potential molecular targets amenable to intervention with small-molecule inhibitors. Ultimately, we propose future directions for the development of therapeutic strategies that optimize cancer treatment outcomes by modulating the PI3K family.

Seasonal and interannual variations of nutrients in the Subei Shoal and their implication for the world's largest green tide.

The world's largest "green tide" (Ulva prolifera) has occurred every year since 2007 in the Yellow Sea. The Subei Shoal area is thought to be the origin of the green tide. Based on field data from 2016 to 2023, seasonal and interannual variations of dissolved nutrients and their ecological effects in the Subei Shoal were analyzed. Spatial distribution of dissolved inorganic nitrogen (DIN), dissolved inorganic phosphorus (DIP) and dissolved silicate (DSi) showed clear terrestrial sources, while ammonia (NH4-N) and dissolved organic nitrogen (DON) were not solely controlled by terrestrial sources. The seasonal variations of NH4-N, DIN, DON, DIP and DSi concentrations were significant, and the interannual variations of DIN, DON, DIP and DSi concentrations showed general decreasing trends from 2016 to 2023. The key factors affecting the seasonal and interannual variations of DIN and DIP concentrations were terrestrial input, aquaculture wastewater discharge, atmospheric deposition, submarine groundwater discharge and macroalgae absorption, while the dominant factor determining the variations of DSi concentrations was terrestrial input. NH4-N and DON concentrations were mainly influenced by aquaculture wastewater discharge and the absorption and release of macroalgae. The high nutrient concentrations in the Subei Shoal throughout the year provided sufficient material basis for the growth of Ulva prolifera in the source area of green tide outbreak.

Toll-like receptor 4 deficiency in Purkinje neurons drives cerebellar ataxia by impairing the BK channel-mediated after-hyperpolarization and cytosolic calcium homeostasis.

Toll-like receptor (TLR) 4 contributes to be the induction of neuroinflammation by recognizing pathology-associated ligands and activating microglia. In addition, numerous physiological signaling factors act as agonists or antagonists of TLR4 expressed by non-immune cells. Recently, TLR4 was found to be highly expressed in cerebellar Purkinje neurons (PNs) and involved in the maintenance of motor coordination through non-immune pathways, but the precise mechanisms remain unclear. Here we report that mice with PN specific TLR4 deletion (TLR4PKO mice) exhibited motor impairments consistent with cerebellar ataxia, reduced PN dendritic arborization and spine density, fewer parallel fiber (PF) - PN and climbing fiber (CF) - PN synapses, reduced BK channel expression, and impaired BK-mediated after-hyperpolarization, collectively leading to abnormal PN firing. Moreover, the impaired PN firing in TLR4PKO mice could be rescued with BK channel opener. The PNs of TLR4PKO mice also exhibited abnormal mitochondrial structure, disrupted mitochondrial endoplasmic reticulum tethering, and reduced cytosolic calcium, changes that may underly abnormal PN firing and ultimately drive ataxia. These results identify a previously unknown role for TLR4 in regulating PN firing and maintaining cerebellar function.

Functional Characterization of Odorant Receptors for Sex Pheromone (Z)-11-Hexadecenol in Orthaga achatina.

Pheromone receptor (PR)-mediated transduction of sex pheromones to electrophysiological signals is the basis for sex pheromone communication. Orthaga achatina, a serious pest of the camphor tree, uses a mixture of four components (Z11-16:OAc, Z11-16:OH, Z11-16:Ald, and Z3,Z6,Z9,Z12,Z15-23:H) as its sex pheromone. In this study, we identified five PR genes (OachPR1-5) by phylogenetic analysis. Further RT-PCR and qPCR experiments showed that PR1-3 were specifically expressed in male antennae, while PR4 was significantly female-biased in expression. Functional characterization using the XOE-TEVC assay demonstrated that PR1 and PR3 both responded strongly to Z11-16:OH, while PR1 and PR3 had a weak response to Z3,Z6,Z9,Z12,Z15-23:H and Z11-16:Ald, respectively. Finally, two key amino acid residues (N78 and R331) were confirmed to be essential for binding of PR3 with Z11-16:OH by molecular docking and site-directed mutagenesis. This study helps understand the sex pheromone recognition molecular mechanism of O. achatina.

Sirt1 m6A modification-evoked Leydig cell senescence promotes Cd-induced testosterone decline.

Diminished testosterone levels have been documented as a key factor in numerous male health disorders. Both human and animal studies have consistently demonstrated that cadmium (Cd), a pervasive environmental heavy metal, results in decreased testosterone levels. However, the exact mechanism through which Cd interferes with testosterone synthesis remains incompletely elucidated. This research sought to examine the impact of cellular senescence on Cd-suppressed testosterone synthesis. We also investigated the related m6A modification mechanism. The results demonstrated that Cd (100 mg/L) led to a decrease in testosterone levels, along with downregulated expression of testosterone synthase in C57BL/6 N male mice. Furthermore, Cd significantly increased ß-galactosidase staining intensity, senescence-related proteins, and senescence-related secretory phenotypes in mouse testicular Leydig cells. Subsequent investigations revealed that Cd decreased the mRNA and protein levels of NAD-dependent deacetylase Sirtuin-1 (SIRT1) in Leydig cells. Mechanistically, mice treated with resveratrol (50 mg/kg), a specific SIRT1 activator, mitigated Leydig cell senescence and reversed Cd-reduced testosterone levels in mouse testes. These effects were also restored by SIRT1 overexpression in Leydig cells. Additionally, we found that Cd increased the level of methyltransferase enzyme METTL3 and Sirt1 m6A modification in Leydig cells. Mettl3 siRNA effectively restored Cd-enhanced Sirt1 m6A level and reversed Cd-downregulated Sirt1 mRNA expression in Leydig cells. Overall, our findings suggest that Cd exposure inhibits testosterone synthesis via Sirt1 m6A modification-mediated senescence in mouse testes. These results offer an experimental basis for investigating the causes and potential treatments of hypotestosteronemia induced by environmental factors.

Structural analysis of the human C5a-C5aR1 complex using cryo-electron microscopy.

The complement system is a complex network of proteins that plays a crucial role in the innate immune response. One important component of this system is the C5a-C5aR1 complex, which is critical in the recruitment and activation of immune cells. In-depth investigation of the activation mechanism as well as biased signaling of the C5a-C5aR1 system will facilitate the elucidation of C5a-mediated pathophysiology. In this study, we determined the structure of C5a-C5aR1-Gi complex at a high resolution of 3 Šusing cryo-electron microscopy (Cryo-EM). Our results revealed the binding site of C5a, which consists of a polar recognition region on the extracellular side and an amphipathic pocket within the transmembrane domain. Furthermore, we found that C5a binding induces conformational changes of C5aR1, which subsequently leads to the activation of G protein signaling pathways. Notably, a key residue (M265) located on transmembrane helix 6 (TM6) was identified to play a crucial role in regulating the recruitment of ß-arrestin driven by C5a. This study provides more information about the structure and function of the human C5a-C5aR1 complex, which is essential for the proper functioning of the complement system. The findings of this study can also provide a foundation for the design of new pharmaceuticals targeting this receptor with bias or specificity.