CD147 mediates S protein pseudovirus of SARS-CoV-2 infection and its induction of spermatogonia apoptosis.

Male cases diagnosed COVID-19 with more complications and higher mortality compared with females, and the overall consequences of male sex hormones and semen parameters deterioration were observed in COVID-19 patients, whereas the involvement and mechanism for spermatogenic cell remains unclear. The study was aimed to investigate the infection mode of S protein (D614G) pseudovirus (pseu-S-D614G) to spermatogenic cells, as well as the influence on cell growth. Both mouse spermatogonia (GC-1 cell, immortalized spermatogonia) and spermatocyte (GC-2 cell, immortalized spermatocytes) were used to detect the infection of pseu-S-D614G of SARS-CoV-2, and further explored the effect of SARS-CoV-2-spike protein (S-protein) and SARS-CoV-2-spike protein (omicron) (O-protein) on GC-1 cell apoptosis and proliferation. The data showed that the pseu-S-D614G invaded into GC-1 cells through either human ACE2 (hACE2) or human CD147 (hCD147), whereas GC-2 cells were insensitive to viral infection. In addition, the apoptosis and proliferation suppression inflicted by S-protein and O-protein on GC-1 cells was through Bax-Caspase3 signaling rather than arresting cell cycle progression. These findings suggest that CD147, apart from ACE2, may be a potential receptor for SARS-CoV-2 infection in testicular tissues, and that the apoptotic effect was induced in spermatogonia cells by S-protein or O-protein, eventually resulted in the damage to male fertility.

Systematically quantifying the dynamic characteristics of PM2.5 in multiple indoor environments in a plateau city: Implication for internal contribution.

People generally spend most of their time indoors, making a comprehensive evaluation of air pollution characteristics in various indoor microenvironments of great significance for accurate exposure estimation. In this study, field measurements were conducted in Kunming City, Southwest China, using real-time PM2.5 sensors to characterize indoor PM2.5 in ten different microenvironments including three restaurants, four public places, and three household settings. Results showed that the daily average PM2.5 concentrations in restaurants, public spaces, and households were 78.4 ± 24.3, 20.1 ± 6.6, and 18.0 ± 4.3 µg/m3, respectively. The highest levels of indoor PM2.5 in restaurants were owing to strong internal emissions from cooking activities. Dynamic changes showed that indoor PM2.5 levels increased during business time in restaurants and public places, and cooking time in residential kitchens. Compared with public places, restaurants generally exhibit more rapid increases in indoor PM2.5 due to cooking activities, which can elevate indoor PM2.5 to high levels (5.1 times higher than the baseline) in a short time. Furthermore, indoor PM2.5 in restaurants were dominated by internal emissions, while outdoor penetration contributed mostly to indoor PM2.5 in public places and household settings. Results from this study revealed large variations in indoor PM2.5 in different microenvironments, and suggested site-specific measures for indoor PM2.5 pollution alleviation.

Hypoxia-induced TRPM7 promotes glycolytic metabolism and progression in hepatocellular carcinoma.

BACKGROUND: Hypoxia disrupts glucose metabolism in hepatocellular carcinoma (HCC). Transient receptor potential cation channel, subfamily M, member 7 (TRPM7) plays an ontogenetic role. Thus, we aimed to explore the regulation of TRPM7 by hypoxia-induced factor (HIF) and its underlying mechanisms in HCC. METHODS: hypoxia was induced in multiple HCC cells using 1% O2 or CoCl2 treatment, and subsequently blocked using siRNAs targeting HIF-1α or HIF-2α as well as a HIF-1α protein synthesis inhibitor. The levels of HIF-1α and TRPM7 were assessed using quantitative PCR (qPCR) and Western blot analysis. Chromatin immunoprecipitation (ChIP) and luciferase assays were performed to observe the regulation of TRPM7 promoter regions by HIF-1α. A PCR array was utilized to screen glucose metabolism-related enzymes in HEK293 cells overexpressing TRPM7 induced by tetracycline, and then verified in TRPM7-overexpressed huh7 cells. Finally, CCK-8, transwell, scratch and tumor formation experiments in nude mice were conducted to examine the effect of TRPM7 on proliferation and metastasis in HCC. RESULTS: Exposure to hypoxia led to increase the levels of TRPM7 and HIF-1α in HCC cells, which were inhibited by HIF-1α siRNA or enhanced by HIF-1α overexpression. HIF-1α directly bound to two hypoxia response elements (HREs) in the TRPM7 promoter. Several glycolytic metabolism-related enzymes, were simultaneously upregulated in HEK293 and huh7 cells overexpressing TRPM7 during hypoxia. In vitro and in vivo experiments demonstrated that TRPM7 promoted the proliferation and metastasis of HCC cells. CONCLUSIONS: TRPM7 was directly transcriptionally regulated by HIF-1α, leading to glycolytic metabolic reprogramming and the promotion of HCC proliferation and metastasis in vitro and in vivo. Our findings suggest that TRPM7 might be a potential diagnostic indicator and therapeutic target for HCC.

5- methylcytidine effectively improves spermatogenesis recovery in busulfan-induced oligoasthenospermia mice.

The function and regulatory mechanisms of 5-methylcytidine (m5C) in oligoasthenospermia remain unclear. In this study, we made a mouse model of oligoasthenospermia through the administration of busulfan (BUS). For the first time, we demonstrated that m5C levels decreased in oligoasthenospermia. The m5C levels were upregulated through the treatments of 5-methylcytidine. The testicular morphology and sperm concentrations were improved via upregulating m5C. The cytoskeletal regenerations of testis and sperm were accompanying with m5C treatments. m5C treatments improved T levels and reduced FSH and LH levels. The levels of ROS and MDA were significantly reduced through m5C treatments. RNA sequencing analysis showed m5C treatments increased the expression of genes involved in spermatid differentiation/development and cilium movement. Immunofluorescent staining demonstrated the regeneration of cilium and quantitative PCR (qPCR) confirmed the high expression of genes involved in spermatogenesis. Collectively, our findings suggest that the upregulation of m5C in oligoasthenospermia facilitates testicular morphology recovery and male infertility via multiple pathways, including cytoskeletal regeneration, hormonal levels, attenuating oxidative stress, spermatid differentiation/development and cilium movement. m5C may be a potential therapeutic agent for oligoasthenospermia.

Ursonic acid attenuates spermatogenesis in oligozoospermia mice through inhibiting ferroptosis.

Ursonic acid (UNA) is a natural pentacyclic triterpene found in some medicinal plants and foods. The reproductive protective effect of UNA was evaluated in a mouse model of oligozoospermia induced by busulfan (BUS) at 30 mg/kg b.w.. The mice were initially divided into groups with UNA concentrations of 10, 30, 50, 100 mg/kg. Subsequently, based on sperm parameters, the optimal concentration of 50 mg/kg was identified. As a control, an additional group was supplemented with ursolic acid at a concentration of 50 mg/kg. The results indicated that BUS caused the loss of spermatogenic cells in testis, the decrease of sperm in epididymis, the disorder of testicular cytoskeleton, the decrease of serum sex hormones such as testosterone which induced an increase in feedback of androgen receptor and other testosterone-related proteins, the increase of malondialdehyde and reactive oxygen species levels and the increase of ferroptosis in testis while UNA successfully reversed these injuries. High-throughput sequencing revealed that UNA administration significantly upregulated the expression of genes associated with spermatogenesis, such as Tnp1, Tnp2, Prm1, among others. These proteins are crucial in the histone to protamine transition during sperm chromatin remodeling. Network pharmacology analysis reveals a close association between UNA and proteins related to the transformation of histones to protamine. Molecular docking studies reveal that UNA can interact with the ferroptosis-inhibiting gene SLC7A11, thereby modulating ferroptosis. Taken together, UNA alleviated BUS-induced oligozoospermia by regulating hormone secretion, mitigating oxidative stress and promoting recovery of spermatogenesis by inhibiting the ferroptosis.

Particulate polycyclic aromatic hydrocarbons in rural households burning solid fuels in Xuanwei County, Southwest China: occurrence, size distribution, and health risks.

The study is about the size distribution and health risks of polycyclic aromatic hydrocarbons (PAHs) in indoor environment of Xuanwei, Southwest China particle samples were collected by Anderson 8-stage impactor which was used to gather particle samples to nine size ranges. Size-segregated samples were collected in indoor from a rural village in Xuanwei during the non-heating and heating seasons. The results showed that the total concentrations of the indoor particulate matter (PM) were 757 ± 60 and 990 ± 78 µg/m3 in non-heating and heating seasons, respectively. The total concentration of indoor PAHs reached to 8.42 ± 0.53 µg/m3 in the heating season, which was considerably greater than the concentration in the non-heating season (2.85 ± 1.72 µg/m3). The size distribution of PAHs showed that PAHs were mainly enriched in PMs with the diameter <1.1 µm. The diagnostic ratios (DR) and principal component analysis (PCA) showed that coal and wood for residential heating and cooking were the main sources of indoor PAHs. The results of the health risk showed that the total deposition concentration (DC) in the alveolar region (AR) was 0.25 and 0.68 µg/m3 in the non-heating and heating seasons respectively. Throughout the entire sampling periods, the lifetime cancer risk (R) based on DC of children and adults varied between 3.53 ×10-5 to 1.79 ×10-4. During the heating season, the potential cancer risk of PAHs in adults was significant, exceeding 10-4, with a rate of 96%.

Single-cell RNA sequencing analysis of the temporomandibular joint condyle in 3 and 4-month-old human embryos.

BACKGROUND: The temporomandibular joint (TMJ) is a complex joint consisting of the condyle, the temporal articular surface, and the articular disc. Functions such as mastication, swallowing and articulation are accomplished by the movements of the TMJ. To date, the TMJ has been studied more extensively, but the types of TMJ cells, their differentiation, and their interrelationship during growth and development are still unclear and the study of the TMJ is limited. The aim of this study was to establish a molecular cellular atlas of the human embryonic temporomandibular joint condyle (TMJC) by single-cell RNA sequencing, which will contribute to understanding and solving clinical problems. RESULTS: Human embryos at 3 and 4 months of age are an important stage of TMJC development. We performed a comprehensive transcriptome analysis of TMJC tissue from human embryos at 3 and 4 months of age using single-cell RNA sequencing. A total of 16,624 cells were captured and the gene expression profiles of 15 cell clusters in human embryonic TMJC were determined, including 14 known cell types and one previously unknown cell type, "transition state cells (TSCs)". Immunofluorescence assays confirmed that TSCs are not the same cell cluster as mesenchymal stem cells (MSCs). Pseudotime trajectory and RNA velocity analysis revealed that MSCs transformed into TSCs, which further differentiated into osteoblasts, hypertrophic chondrocytes and tenocytes. In addition, chondrocytes (CYTL1high + THBS1high) from secondary cartilage were detected only in 4-month-old human embryonic TMJC. CONCLUSIONS: Our study provides an atlas of differentiation stages of human embryonic TMJC tissue cells, which will contribute to an in-depth understanding of the pathophysiology of the TMJC tissue repair process and ultimately help to solve clinical problems.

[Characterization and Health Risk of Heavy Metals in PM2.5 from Road Fugitive Dust in Five Cities of Yunnan Province].

In order to study the contents, sources, and health risk of PM2.5 in road fugitive dust in Yunnan, road fugitive dust samples were collected from five typical cities including Kunming, Baoshan, Wenshan, Zhaotong, and Yuxi. Particulate matter resuspension technology was used to levitate the dust samples and collect PM2.5. Eight heavy metals including chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), selenium (As), cadmium (Cd), and lead (Pb) in PM2.5 were detected using ICP-MS. The results showed that the contents of Cr, Ni, Cu, Zn, and Pb in road fugitive dust seriously exceeded the background values of Yunnan soil. The enrichment factors showed that most of the heavy metals in PM2.5 of road fugitive dust in the five cities of Yunnan were moderately enriched and strongly enriched, which were greatly influenced by human activities. The results of correlation analysis and principal component analysis showed that the heavy metals in PM2.5 of road fugitive dust in Yunnan were all affected by soil and traffic sources. The other sources varied greatly in different cities:Kunming was affected by iron and steel melting sources, Baoshan and Yuxi were affected by non-ferrous metal smelting sources, and Zhaotong was affected by coal sources. Health risk analysis showed that Cr, Pb, and As in road fugitive dust PM2.5 had non-carcinogenic risk in children in Kunming, Yuxi, and Zhaotong, respectively, and Cr in Kunming also had a lifetime carcinogenic risk.

H2O as the Hydrogen Donor: Stereo-Selective Synthesis of E- and Z-Alkenes by Palladium-Catalyzed Semihydrogenation of Alkynes.

It is very desirable to develop a facile controllable method for selective semihydrogenation of alkynes to alkenes with a cheap and safe hydrogen donor but remains a big challenge. H2O is one of the best choices of the transfer hydrogenation agent of the world, and the development of methods for synthesizing E- and Z-alkenes using H2O as the hydrogen source is worthwhile. In this article, a palladium-catalyzed synthesis of E- and Z-alkenes from alkynes using H2O as the hydrogenation agent was reported. The use of di-tert-butylphosphinous chloride (t-Bu2PCl) and triethanolamine/sodium acetate (TEOA/NaOAc) was essential for the stereo-selective semihydrogenation of alkynes. The general applicability of this procedure was highlighted by the synthesis of more than 48 alkenes, with good yields and high stereoselectivities.

Distribution of environmentally persistent free radicals in size-segregated PMs emitted from residential biomass fuel combustion.

Environmentally persistent free radicals (EPFRs) are considered as an emerging pollutant due to their potential environmental risks, but the distribution characteristics of particulate matters (PMs)-EPFRs from residential combustion source are poorly understood. In this study, biomass (corn straw, rice straw, pine and jujube wood) combustion was studied in lab-controlled experiments. More than 80% of PM-EPFRs were distributed in PMs with aerodynamic diameter (dae) ≤ 2.1 µm, and their concentration in fine PMs was about 10 times that in coarse PM (2.1 µm ≤ dae ≤ 10 µm). The detected EPFRs were carbon-centered free radicals adjacent to oxygen atoms or a mixture of oxygen- and carbon-centered radicals. The concentrations of EPFRs in coarse and fine PMs were positively correlated with char-EC, but the EPFRs in fine PMs exhibited a negative correlation with soot-EC (p < 0.05). The increase of PM-EPFRs signals with the increased dilution ratio during pine wood combustion was more significant than that from rice straw, which may be resulted from the interactions between the condensable volatiles and the transition metals. Our study provides useful information for better understanding the formation of combustion-derived PM-EPFRs, and will be instructive for its purposeful emissions control.

Epididymis cell atlas in a patient with a sex development disorder and a novel NR5A1 gene mutation.

This study aims to characterize the cell atlas of the epididymis derived from a 46,XY disorders of sex development (DSD) patient with a novel heterozygous mutation of the nuclear receptor subfamily 5 group A member 1 (NR5A1) gene. Next-generation sequencing found a heterozygous c.124C>G mutation in NR5A1 that resulted in a p.Q42E missense mutation in the conserved DNA-binding domain of NR5A1. The patient demonstrated feminization of external genitalia and Tanner stage 1 breast development. The surgical procedure revealed a morphologically normal epididymis and vas deferens but a dysplastic testis. Microfluidic-based single-cell RNA sequencing (scRNA-seq) analysis found that the fibroblast cells were significantly increased (approximately 46.5%), whereas the number of main epididymal epithelial cells (approximately 9.2%), such as principal cells and basal cells, was dramatically decreased. Bioinformatics analysis of cell-cell communications and gene regulatory networks at the single-cell level inferred that epididymal epithelial cell loss and fibroblast occupation are associated with the epithelial-to-mesenchymal transition (EMT) process. The present study provides a cell atlas of the epididymis of a patient with 46,XY DSD and serves as an important resource for understanding the pathophysiology of DSD.

ß-Defensin 19/119 mediates sperm chemotaxis and is associated with idiopathic infertility.

Sperm chemotaxis is required for guiding sperm toward the egg. However, the molecular identity of physiological chemoattractant and its involvement in infertility remain elusive. Here, we identify DEFB19/119 (mouse/human orthologs) as a physiological sperm chemoattractant. The epithelia of the female reproductive tract and the cumulus-oocyte complex secrete DEFB19/119 that elicits calcium mobilization via the CatSper channel and induces sperm chemotaxis in capacitated sperm. Manipulating the level of DEFB19 in mice determines the number of sperm arriving at the fertilization site. Importantly, we identify exon mutations in the DEFB119 gene in idiopathic infertile women with low level of DEFB119 in the follicular fluid. The level of DEFB119 correlates with the chemotactic potency of follicular fluid and predicts the infertile outcome with positive correlation. This study reveals the pivotal role of DEFB19/119 in sperm chemotaxis and demonstrates its potential application in the diagnosis of idiopathic infertility.

Dragon-Boat-Type Heptathienoacenes: Synthesis, Structures, and Their Applications in OFETs.

A novel synthetic strategy for efficient construction of dragon-boat-type heptathienoacenes (DBHTs) via the α-ß position carbon-carbon cross-coupling between two dithienothiophenes is employed. Their crystal structures are confirmed by X-ray single-crystal analysis. The first thin film FET devices of heptathienoacenes are fabricated using OTS-treated SiO2/Si substrates, in which DBHT-5-based devices exhibit an unprecedented highest hole mobility value of 1.15 cm2 V-1 s-1 and on/off ratios over 106 with a threshold voltage of 0 V.

Mass Concentration, Source and Health Risk Assessment of Volatile Organic Compounds in Nine Cities of Northeast China.

From April 2008 to July 2009, ambient measurements of 58 volatile organic compounds (VOCs), including alkanes, alkenes, and aromatics, were conducted in nine industrial cities (Shenyang, Fushun, Changchun, Jilin, Harbin, Daqing, Huludao, Anshan and Tianjin) of the Northeast Region, China (NRC). Daqing had the highest concentration of VOCs (519.68 ± 309.88 µg/m3), followed by Changchun (345.01 ± 170.52 µg/m3), Harbin (231.14 ± 46.69 µg/m3), Jilin (221.63 ± 34.32 µg/m3), Huludao (195.92 ± 103.26 µg/m3), Fushun (135.43 ± 46.01 µg/m3), Anshan (109.68 ± 23.27 µg/m3), Tianjin (104.31 ± 46.04 µg/m3), Shenyang (75.2 ± 40.09 µg/m3). Alkanes constituted the largest percentage (>40%) in concentrations of the quantified VOCs in NRC, and the exception was Tianjin dominated by aromatics (about 52.34%). Although alkanes were the most abundant VOCs at the cities, the most important VOCs contributing to ozone formation potential (OFP) were alkenes and aromatics. Changchun had the highest OFP (537.3 µg/m3), Tianjin had the lowest OFP (111.7 µg/m3). The main active species contributing to OFP in the nine cities were C2~C6 alkanes, C7~C8 aromatic hydrocarbons, individual cities (Daqing) contained n-hexane, propane and other alkane species. Correlation between individual hydrocarbons, B/T ratio and principal component analysis model (PCA) were deployed to explore the source contributions. The results showed that the source of vehicle exhausts was one of the primary sources of VOCs in all nine cities. Additionally, individual cities, such as Daqing, petrochemical industry was founded to be an important source of VOCs. The results gained from this study provided a large of useful information for better understanding the characteristics and sources of ambient VOCs incities of NRC. The non-carcinogenic risk values of the nine cities were within the safe range recognized by the U.S. Environmental Protection Agency (HQ < 1), and the lifetime carcinogenic risk values of benzene were 3.82 × 10−5~1.28 × 10−4, which were higher than the safety range specified by the US Environmental Protection Agency (R < 1.00 × 10−6). The results of risk values indicated that there was a risk of cancer in these cities.

Interfering with CSE1L/CAS inhibits tumour growth via C3 in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. However, the treatment regimens for TNBC are limited. Chromosome segregation 1-like (CSE1L), also called cellular apoptosis susceptibility protein (CAS), is highly expressed in breast cancer and plays a crucial role in the progression of various tumours. However, the involvement of CAS in TNBC remains elusive. In this study, we showed that the expression of CAS was higher in TNBC samples than in non-TNBC samples in the Gene Expression Omnibus database. Knockdown of CAS inhibited MDA-MB-231 cell growth, migration and invasion. Further RNA-seq analysis revealed that complement pathway activity was significantly elevated. Of note, complement component 3 (C3), the key molecule in the complement pathway, was significantly upregulated, and the expression of C3 was negatively correlated with that of CAS in breast cancer. Lower C3 expression was related to poor prognosis. Interestingly, the expression level of C3 was positively correlated with the infiltration of multiple immune cells. Taken together, our findings suggest that CAS participates in the development of TNBC through C3-mediated immune cell suppression and might constitute a potential therapeutic target for TNBC.

[Pollution Characteristics and Health Risk of Heavy Metals in Fugitive Dust Around Zhaotong City].

In order to explore the pollution characteristics and health risks of heavy metals in fugitive dust around the urban areas of Zhaotong City, road dust and soil dust samples were collected in the Zhaoyang District of Zhaotong City in May 2019. The dust samples were suspended using a particle resuspension system to obtain PM2.5 (particulate matter with an aerodynamic diameter less than or equal to 2.5 µm). The concentrations of Ca, Al, Fe, Mg, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb in PM2.5 were quantified by ICP-MS and ICP-OES. By analyzing 10 types of heavy metals in PM2.5, the results showed that the average concentration of Mn was the highest in the soil fugitive dust, followed by Cr, Ni, Zn, Cu, Co, Pb, V, As, and Cd. The average concentration of Zn in the road fugitive dust was the highest, followed by Mn, Cu, Cr, Pb, Ni, As, Co, V, and Cd. The enrichment factor (EF) indicated that Cd was strongly enriched in the two types of fugitive dust. The EFs of Cu, Zn, and Pb in road fugitive dust showed a moderate enrichment, and they were higher than those in soil fugitive dust. Correlation and principal component analysis showed that heavy metals in the two types of fugitive dust were affected by coal burning sources. At the same time, heavy metals in soil fugitive dust were affected by agricultural activity sources, and heavy metals in road fugitive dust were affected by traffic sources. The results of the health risk assessment indicated that the carcinogenic risks of Cr, Co, Ni, As, and Cd in soil fugitive dust were higher than those in road fugitive dust. The non-carcinogenic risks of heavy metals in the two types of fugitive dust for children were higher than those for adults, and the non-carcinogenic risks of Cu, Zn, and Pb in road fugitive dust were higher than those in soil fugitive dust.

The N501Y Mutation of SARS-CoV-2 Spike Protein Impairs Spindle Assembly in Mouse Oocytes.

The COVID-19 pandemic has been continuing for one and a half year and caused a profound effect on human health. Although advanced researches and literatures are gathered, the influences of SARS-CoV-2 on the reproduction systems are largely unknown, especially on the female reproductive functions. The purpose of this study was to investigate the effect of N501Y mutant spike protein of SARS-Cov-2 on oocyte maturation. We demonstrated that the N501Y mutant of SARS-CoV-2 spike protein impaired the mouse oocyte maturation accompanied by abnormal spindle assembly. Furthermore, the mean spindle length and the plate width were significantly increased in the N501Y-treated group compared to the control group. These results indicated the potential impairment of maturation of the oocytes caused by the infection of SARS-CoV-2, albeit current results were derived from mouse oocytes. The present study provided a theoretical basis for the attention of female reproductive health during the COVID-19 pandemic and shed light on the potential risk of SARS-CoV-2 in the successful rate of assisted reproduction.

Concentrations, Source Characteristics, and Health Risk Assessment of Toxic Heavy Metals in PM2.5 in a Plateau City (Kunming) in Southwest China.

To explore the mass concentration levels and health risks of heavy metals in the air in dense traffic environments, PM2.5 samples were collected at three sites in the city of Kunming in April and October 2013, and January and May 2014. Ten heavy metals--V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd and Pb--were analyzed by ICP-MS, and the results showed PM2.5 concentrations significantly higher in spring and winter than in summer and autumn, especially for Zn and Pb. The concentration of heavy metals on working days is significantly higher, indicating that vehicle emissions are significant contributors. An enrichment factor analysis showed that Cr, Mn, Ni, Cu, Zn, As, Cd and Pb come mainly from anthropogenic sources, while V and Co may be both anthropogenic and natural. The correlation and principal component analysis (PCA) showed that Ni, Cu, Zn, Cd and Pb mainly come from vehicles emissions and metallurgical industries; Cr and Mn, from vehicles emissions and road dust; and As, mainly from coal combustion. The health risk assessment shows that the non-carcinogenic risk thresholds of the heavy metals in PM2.5 to children and adult men and women are all less than 1. The carcinogenic risk of Cr for men and women in traffic-intensive areas exceeds 10-4, reaching 1.64 × 10-4 and 1.4 × 10-4, respectively.

Spatio-temporal landscape of mouse epididymal cells and specific mitochondria-rich segments defined by large-scale single-cell RNA-seq.

Spermatozoa acquire their fertilizing ability and forward motility during epididymal transit, suggesting the importance of the epididymis. Although the cell atlas of the epididymis was reported recently, the heterogeneity of the cells and the gene expression profile in the epididymal tube are still largely unknown. Considering single-cell RNA sequencing results, we thoroughly studied the cell composition, spatio-temporal differences in differentially expressed genes (DEGs) in epididymal segments and mitochondria throughout the epididymis with sufficient cell numbers. In total, 40,623 cells were detected and further clustered into 8 identified cell populations. Focused analyses revealed the subpopulations of principal cells, basal cells, clear/narrow cells, and halo/T cells. Notably, two subtypes of principal cells, the Prc7 and Prc8 subpopulations were enriched as stereocilia-like cells according to GO analysis. Further analysis demonstrated the spatially specific pattern of the DEGs in each cell cluster. Unexpectedly, the abundance of mitochondria and mitochondrial transcription (MT) was found to be higher in the corpus and cauda epididymis than in the caput epididymis by scRNA-seq, immunostaining, and qPCR validation. In addition, the spatio-temporal profile of the DEGs from the P42 and P56 epididymis, including transiting spermatozoa, was depicted. Overall, our study presented the single-cell transcriptome atlas of the mouse epididymis and revealed the novel distribution pattern of mitochondria and key genes that may be linked to sperm functionalities in the first wave and subsequent wave of sperm, providing a roadmap to be emulated in efforts to achieve sperm maturation regulation in the epididymis.