Case Report: Scalp pityriasis versicolor may be a neglected problem.

Pityriasis versicolor, a common skin fungal infection, is typically observed on trunk and limb skin. Here, we highlight an unusual presentation: scalp involvement, often overlooked due to its asymptomatic, mildly scaly patches. We report four pediatric cases, emphasizing the potential underestimation of this scalp variant. This case series underscores the importance of considering this diagnosis in patients with unexplained scalp hypopigmentation, especially in males with short hair who may readily notice these subtle changes. The report contributes to the understanding of this variant's clinical presentation and emphasizes the need for awareness among clinicians to ensure accurate diagnosis and appropriate management.

Mapping global distributions of clay-size minerals via soil properties and machine learning techniques.

Clay-size mineral is a vital ingredient of soil that influences various environment behaviors. It is crucial to establish a global distribution map of clay-size minerals to improve the recognition of environment variations. However, there is a huge gap of lacking some mineral contents in poorly accessible remote areas. In this work, machine learning (ML) approaches were conducted to predict the mineral contents and analyze their global abundance changes through the relationship between soil properties and mineral distributions. The average content of kaolinite, illite, smectite, vermiculite, chlorite, and feldspar were predicated to be 28.69 %, 22.30 %, 12.42 %, 5.43 %, 5.03 %, and 1.44 % respectively. Model interpretation showed that topsoil bulk density and drainage class were the most significant factors for predicting all six minerals. It could be seen from the feature importance analysis that bulk density notably reflected the distribution of 2:1 layered minerals more than that of 1:1 mineral. High drainage favored secondary minerals development, while low drainage was more benefited for primary minerals. Moreover, the content variation of different minerals aligned with the distribution of corresponding soil properties, which affirmed the accuracy of established models. This study proposed a new approach to predict mineral contents through soil properties, which filled a necessary step of understanding the geochemical cycles of soil-related processes.

The application of interdisciplinary and cross-grade learning teaching method in stomatology course.

OBJECTIVES: The first purpose of this project was to determine whether an interdisciplinary and cross-grade teaching model impacts students' learning enthusiasm and their views on this teaching method. The second purpose was to determine whether the model positively impacted students' theoretical course exam scores. METHODS: We recruited 203 pre-clinical undergraduate dental students, including 104 third- and 99 fourth-grade students. The study was conducted in experimental classes for the "Dental Materials" course in the third-grade program (focusing on cement material mixing techniques) and the "Endodontics Practice" course in the fourth-grade program (focusing on the preparation and filling of Class II cavities). The interventions were implemented before, during, and after the class. We assessed students' attitudes toward this teaching method and changes in their course scores. RESULTS: The survey questionnaire assessed the students' levels of learning enthusiasm, professional competence, and classroom effectiveness, all of which demonstrated significant improvement. The average scores for lab operations, quizzes, and usual performance exhibited a substantial increase (p < 0.001). The average score of the final examination increased from 75.61 to 78.17 (p = 0.008). CONCLUSIONS: Significant enhancement in students' learning attitudes, course scores, collaborative abilities, and innovation capacities were observed following the interdisciplinary and cross-grade teaching method. Furthermore, the overall classroom efficiency improved. This teaching method can expand the scope of future research.

Case Report: Itraconazole Oral Solution Continuous Therapy for Infantile Tinea Capitis.

Tinea capitis is a common fungal infection caused by dermatophytes in children, but it is rare in infants. Although oral itraconazole has been widely used to treat tinea capitis, its use in infants is limited due to its low prevalence in this age group. A previous study reported the effectiveness of itraconazole continuous therapy in treating infantile tinea capitis caused by Microsporum canis. However, this approach has not been extended to tinea capitis caused by other fungi. In this study, we present four cases of infantile tinea capitis treated with continuous itraconazole oral solution therapy (5 mg/kg/day). Two patients were infected with M. canis, one patient with Nannizzia gypsea, and another with Trichophyton tonsurans. This study assesses the efficacy and safety of itraconazole oral solution continuous therapy, expanding our understanding by demonstrating its effectiveness for infantile tinea capitis caused by T. tonsurans and N. gypsea.

[Construction of ecological network with protected areas as the main region in Guangzhou City, China]. / 以自然保护地为主体的广州市域生态网络构建.

In the context of the national ecological security development strategy, constructing regional ecological networks centered on protected areas and ecological corridors has become an urgent issue in protected areas system development of China. We focused on strengthening ecological connections between protected areas in Guangzhou, identified the ecological resource patches, ecological corridors, and ecological nodes by using Invest model, connectivity analysis, circuit theory models, and graph-theoretical network structure evaluation, and constructed an ecological network for the Guangzhou with nature reserves as the core. The results showed that 52 ecological resource patches were identified in the study area, covering a total area of 1450.01 km2. Nature reserves accounted for 76.4% of the total area, forming the main part of the ecological resource patches. 115 ecological corridors were identified, with a total length of 900.56 km and an average length of 7.83 km. Furthermore, 72 ecological key points were identified, covering a total area of 17.57 km2, and 81 ecological breakpoints, with a total area of 35.9 km2. The network structure indices (α=0.65, ß=2.21, and γ=0.77) indicated a reasonably structured and well-connected network. By exploring pathways for constructing regional ecological networks under the protected areas system and enriching the application of circuit theory models in ecological network construction, this study provides scientific basis for regional ecological security and biodiversity conservation.

Characterization of key aroma-active compounds in different types of Douchi based on molecular sensory science approaches.

To attain the differences in the flavor profile of Douchi, the key aroma-active compounds of three types of Douchi were investigated. The "Sauce-like", "Smoky", "Nutty", "Roast", "Caramel", and "Flower" of Douchi were favored by customers. Further, a total of 179 volatile compounds were identified using HS-SPME-GC-MS, and 29 aroma compounds were detected using GC-O-MS. Based on the quantification, 9, 13, and 10 compounds were regarded as aroma-active compounds in Yangjiang Douchi (YJ), Pingjiang Douchi (PJ), and Liuyang Douchi (LY), respectively. Moreover, the mixture of these aroma-active compounds successfully simulated the main aromas of PJ, LY, and YJ. And omission experiments confirmed that guaiacol was the key aroma compound for LY, benzene acetaldehyde, dimethyl trisulfide, and 2-acetyl pyrrole were important for YJ, benzene acetaldehyde and 3,5-diethyl-2-methyl pyrazine notably contributed to key aroma of PJ.

Causal association between genetically predicted circulating immune cell counts and frailty: a two-sample Mendelian randomization study.

Background: Despite the recognized link between immune responses and frailty, the association between immune cell counts and frailty based on previous observational studies remains disputed, with uncertain causal nexus. This study aimed to elucidate causal association between genetically predicted circulating immune cell counts and frailty. Methods: We conducted the two-sample Mendelian randomization (MR) study with independent genetic variants associated with six immune cell subtype counts from genome-wide association studies in 563,946 European individuals. Frailty summary data, assessed via frailty index (FI), was obtained from study comprising 175,226 subjects. Univariate MR, reverse MR and multivariate MR were conducted to comprehensive investigate the association between immune cell counts and FI, with two-step MR analysis for mediation analysis. Results: Univariate MR evidence indicated that among six leukocyte subtype counts, only elevated eosinophil count was significantly correlated with higher FI (ß = 0.059, 95% confidence interval [CI], 0.042-0.078, P=5.63E-11), with no reverse causal relationship identified in reverse MR. In multivariate MR, the causal effect of eosinophil count retained statistical significance (ß = 0.063, 95% CI, 0.021-0.104, P = 0.003). Ultimately, the two-step MR analysis demonstrated two mediators in this causal pathway: asthma (ß= 0.019, 95% CI, 0.013-0.025, P = 35.84E-10, mediated proportion, 31.732%) and rheumatoid arthritis (ß= 0.004, 95% CI, 0.001-0.006, P=1.75E-03, mediated proportion, 6.411%). Conclusions: Within immune cell subtypes, MR evidence indicated only genetically predicted circulating eosinophil count had irreversible and independent causal effect on frailty, with asthma and rheumatoid arthritis possibly serving as partial mediators. The finding stressed the need for further exploring physiological functions of eosinophils in order to develop effective strategies against frailty.

First Report of Charcoal Rot on Tobacco Caused by Macrophomina phaseolina in Hunan Province, China.

Flue-cured tobacco (Nicotiana tabacum L.) is a significant cash crop globally. In August 2022, necrotic lesions on stem associated with root rot and wilting were observed on flue-cured tobacco (Cv. Yunyan 87) in fields located in Banxin village (27.95N,109.60E) of Fenghuang county in Xiangxi Autonomous Prefecture, Hunan Province, China. The affected and damaged area of tobacco is approximately 10 hectares, with adisease incidence of 60%. Lots of small black speckling within the lower stem of the affected plant, vascular tissue changed to black, dry rot, and looked like charcoal breezes. Small pieces were cut from healthy and diseased tissues, surface sterilized with 5% NaClO for 3 min and 75% ethanol for 1 min, rinsed with sterile distilled water and air-drying, incubated on oat medium incubated at 28℃ for five days. These isolates grew fast and produced typical black microsclerotia. The morphological were septate hyphae and microsclerotia. The microsclerotia were black and regularly round, with a 42.5 - 92.9 µm diameter. These morphological features were consistent with Macrophomina phaseolina (Smith and Wyllie 1999). The internal transcribed spacer (ITS) rDNA and translation elongation factor 1-α (TEF1-α) genes of three representative isolates were amplified and sequenced using the primers ITS1/ITS4 and EF1-728F/EF2R (Machado et al. 2019). Our resulting sequences (GenBank accessions OR435093, OR435101, OR435102 for ITS; OR891780, OR891781 and OR891782 for EF1-α) showed 99-100% similarity with M. phaseolina by NCBI blast. Phylogenetic analysis was conducted using MEGA-X software with the NJ method. The combined sequences grouped with isolates to M. phaseolina with 100% bootstrap support. The strain XF22 has been sent to the China General Microbiological Culture Collection Center (CGMCC3.25349). Pathogenicity tests were conducted by inoculating potted plants (six plants per isolate, three times) from 45 day-old tobacco seedlings cv. Yunyan 87. Stems were randomly gently scratched with sterile needles, and a 5 mm agar disc with mycelium of the pathogen was attached to the surface of each wound, with a sterilized agar disc as control. Inoculated seedlings were incubated in growth chambers at 26℃ and 60% RH with a 12 h photoperiod/day. After ten days, symptoms that brown or black lesions on the inoculated lesions were dotted with numerous black, hard microsclerotia similar to those naturally occurring on the diseased plants, but not on the control plants. The same pathogen was re-isolated consistently, fulfilling Koch's postulates. Based on morphological, molecular, and pathogenicity test results, these isolates were identified as M. phaseolina. Charcoal rot of tobacco, caused by M. phaseolina was previously found in Guangxi in 1989 (Zhu et al. 2002), while this is the first report of M. phaseolina causing charcoal rot on flue-cured tobacco in Hunan, China. We speculate that the planting area is influenced by the preceding crop sesame. The soil carries M. phaseolina, which can cause stem rot of sesame, leading to the occurrence of tobacco charcoal rot. Our results indicated that charcoal rot caused by M. phaseolina is a new threat to flue-cured tobacco production and lue-cured tobacco might be acting as a reservoir and spreading this pathogen to other economically crops in China.

IFT27 regulates the long-term maintenance of photoreceptor outer segments in zebrafish.

Approximately a quarter of Retinitis Pigmentosa (RP) is caused by mutations in transport-related genes in cilia. IFT27 (Intraflagellar Transport 27), a core component of the ciliary intraflagellar transport (IFT) system, has been implicated as a significant pathogenic gene in RP. The pathogenic mechanisms and subsequent pathology related to IFT27 mutations in RP are largely obscure. Here, we utilized TALEN technology to create an ift27 knockout (ift27-/-) zebrafish model. Electroretinography (ERG) detection showed impaired vision in this model. Histopathological examinations disclosed that ift27 mutations cause progressive degeneration of photoreceptors in zebrafish, and this degeneration was late-onset. Immunofluorescence labeling of outer segments showed that rods degenerated before cones, aligning with the conventional characterization of RP. In cultured human retinal pigment epithelial cells, we found that IFT27 was involved in maintaining ciliary morphology. Furthermore, decreased IFT27 expression resulted in the inhibition of the Hedgehog (Hh) signaling pathway, including decreased expression of key factors in the Hh pathway and abnormal localization of the ciliary mediator Gli2. In summary, we generated an ift27-/- zebrafish line with retinal degeneration which mimicked the symptoms of RP patients, highlighting IFT27's integral role in the long-term maintenance of cilia via the Hh signaling pathway. This work may furnish new insights into the treatment or delay of RP caused by IFT27 mutations.

Secondary Metabolites from the Genus Eurotium and Their Biological Activities.

Eurotium is the teleomorph genus associated with the section Aspergillus. Eurotium comprises approximately 20 species, which are widely distributed in nature and human environments. Eurotium is usually the key microorganism for the fermentation of traditional food, such as Fuzhuan brick tea, Liupao tea, Meju, and Karebushi; thus, Eurotium is an important fungus in the food industry. Eurotium has been extensively studied because it contains a series of interesting, structurally diverse, and biologically important secondary metabolites, including anthraquinones, benzaldehyde derivatives, and indol diketopiperazine alkaloids. These secondary metabolites have shown multiple biological activities, including antioxidative, antimicrobial, cytotoxic, antitumor, insecticidal, antimalarial, and anti-inflammatory activities. This study presents an up-to-date review of the phytochemistry and biological activities of all Eurotium species. This review will provide recent advances on the secondary metabolites and their bioactivities in the genus Eurotium for the first time and serve as a database for future research and drug development from the genus Eurotium.

Identification of Differential Circular RNA Expression Profiles and Functional Networks in Human Macrophages Induced by Virulent and Avirulent Mycobacterium tuberculosis Strains.

Circular RNAs (circRNAs) are noncoding RNAs with diverse functions. However, most Mycobacterium tuberculosis (M.tb)-related circRNAs remain undiscovered. In this study, we infected THP-1 cells with virulent and avirulent M.tb strains and then sequenced the cellular circRNAs. Bioinformatic analysis predicted 58,009 circRNAs in all the cells. In total, 2035 differentially expressed circRNAs were identified between the M.tb-infected and uninfected THP-1 cells and 1258 circRNAs were identified in the virulent and avirulent M.tb strains. Further, the top 10 circRNAs were confirmed by Sanger sequencing, among which four circRNAs, namely circSOD2, circCHSY1, circTNFRSF21, and circDHTKD1, which were highly differentially expressed in infected cells compared with those in uninfected cells, were further confirmed by ring formation, specific primers, and RNase R digestion. Next, circRNA-miRNA-mRNA subnetworks were constructed, such as circDHTKD1/miR-660-3p/IL-12B axis. Some of the individual downstream genes, such as miR-660-3p and IL-12B, were previously reported to be associated with cellular defense against pathological processes induced by M.tb infection. Because macrophages are important immune cells and the major host cells of M.tb, these findings provide novel ideas for exploring the M.tb pathogenesis and host defense by focusing on the regulation of circRNAs during M.tb infection.

Ferroptosis: action and mechanism of chemical/drug-induced liver injury.

Drug-induced liver injury (DILI) is characterized by hepatocyte injury, cholestasis injury, and mixed injury. The liver transplantation is required for serious clinical outcomes such as acute liver failure. Current studies have found that many mechanisms were involved in DILI, such as mitochondrial oxidative stress, apoptosis, necroptosis, autophagy, ferroptosis, etc. Ferroptosis occurs when hepatocytes die from iron-dependent lipid peroxidation and plays a key role in DILI. After entry into the liver, where some drugs or chemicals are metabolized, they convert into hepatotoxic substances, consume reduced glutathione (GSH), and decrease the reductive capacity of GSH-dependent GPX4, leading to redox imbalance in hepatocytes and increase of reactive oxygen species (ROS) and lipid peroxidation level, leading to the undermining of hepatocytes; some drugs facilitated the autophagy of ferritin, orchestrating the increased ion level and ferroptosis. The purpose of this review is to summarize the role of ferroptosis in chemical- or drug-induced liver injury (chemical/DILI) and how natural products inhibit ferroptosis to prevent chemical/DILI.

Preparation and antibacterial activity of coronarin E derivatives.

Coronarin E is a main diterpene ever isolated from Hedychium yunnanense. With the aim to enlarge its potential application, four butenolide derivatives (compounds 4a, 4b, 5a and 5b) were obtained from coronarin E via synthetic method, and their antibacterial effects were also evaluated. It is noteworthy that compounds 5a and 5b exhibited stronger antibacterial activities against most of the tested bacterial strains than ampicillin and kanamycin, two first- and second-line antimicrobials in clinical. For example, minimum inhibitory concentration (MIC) of 5a, 5b, ampicillin and kanamycin against Acinetobacter baumanii were 2, 1, 8 and 4 µg/mL, respectively, and MIC of the four compounds mentioned above against Klebsiella pneumonia were 1, 0.5, 16 and 4 µg/mL, respectively. The current studies not only enrich the structural diversity of diterpenes derived from Hedychium genus, but also provide potent candidates for the development of antibacterial medicines.

Heat-induced antigen retrieval utilizing modified Tris-EDTA buffer for reprobing of Western blots on nitrocellulose paper.

The development of heat-induced antigen retrieval technologies with Tris-EDTA buffer has dramatically improved immunostaining of specific antigens for routine immunohistochemical detection (Krenacs et al., 2010) [1]. However, little evidence exists on whether heat-Induced antigen retrieval utilizing Tris-EDTA buffer can strip western blot (WB) membranes and allow sequential reprobing. Here, we serendipitously discover that ∼95 °C Tris-EDTA buffer with 0.01% Tween 20 could repeatedly strip the Nitrocellulose membranes (NC). After electroblotting, NC blots were soaked into Tris-EDTA stripping buffer (∼95 °C, 10-25min) and we could perform at least five rounds (the following antibodies used: Vinculin, Atg7, Caspase-3, UBA5, JNK and ERK1/2) stripping in sequential chemiluminescent detections. The NC membranes also show clear western signals and background without losing transferred proteins during the reprobing process of WB. Hence, this study report additional new roles of the heat-Induced antigen retrieval Tris-EDTA buffer with 0.01% Tween 20. The method is simpler, more affordable and harmless for the nitrocellulose paper, which will be helpful for effective reprobing in western blotting applications.

Time-Restricted Feeding Ameliorates Uterine Epithelial Estrogen Receptor α Transcriptional Activity at the Time of Embryo Implantation in Mice Fed a High-Fat Diet.

BACKGROUND: More than 30% of reproductive-age women are obese or overweight. Obesity and exposure to a high-fat diet (HFD) detrimentally affect endometrial development and embryo implantation. We previously reported that time-restricted feeding (TRF) improved ovarian follicular development, but whether and how TRF modulates embryo implantation are poorly understood. OBJECTIVE: We investigated the effect of TRF on embryo implantation. METHODS: In TRF group, mice had 10 h of food free access from 9 pm to 7 am, and fed a normal diet or a HFD. Tail vein injection of Chicago blue dye was used to examine embryo implantation sites at day 5.5 (D5.5) of pregnancy. Serum collected at D0.5 and D4.5 of pregnancy was used to examine the level of estradiol (E2) and progesterone. Uterine estrogen receptor (ER) and progesterone receptor levels and their targeted aquaporins (AQPs) were measured. LC-MS was used to analyze bile acid (BA) composition, and primary hepatocytes were used to test the effects of BA on the expression level of SULT1E1, a key enzyme in estrogen inactivation and elimination. RESULTS: We found that TRF prevented HFD-induced embryo loss and alleviated the defect in luminal closure on D4.5 of pregnancy. The cyclic changes of E2 level were lost in mice fed ad libitum but not in TRF mice on the HFD. The HFD increased ER-α expression and transcriptional activity, which induced AQP3 and AQP5 expression on D4.5 of pregnancy. TRF prevented the negative effect of the HFD on uterine luminal closure. Furthermore, in vitro and in vivo results showed that BA suppressed estrogen degradation by activating liver SULT1E1 expression. CONCLUSIONS: Our findings demonstrated that TRF prevented HFD-induced defects in luminal closure, thereby improving embryonic implantation, and provide novel insights into the effects of dietary intervention on obesity and associated infertility.

Liver-derived FGF21 is required for the effect of time-restricted feeding on high-fat diet-induced fatty liver in mice.

Nonalcoholic fatty liver disease (NAFLD), which leads to insulin resistance, steatosis, and even hepatocellular carcinoma, is the most common chronic liver disease worldwide, however, effective treatment is still lacking. This study determined the role of liver FGF21 and the mechanisms underlying the protective effects of time-restricted feeding (TRF) in NAFLD. FGF21 liver knockout (FGF21 LKO) mice and C57BL/6 wild-type (WT) mice were fed either a normal or a high-fat diet (HFD) for 16 weeks. Mice with diet-induced obesity (DIO) were also used. The mice were fed either ad libitum or in a time-restricted manner. Serum FGF21 levels were significantly increased after 16 weeks of TRF. TRF prevented body weight gain, improved glucose homeostasis, and protected against high-fat diet-induced hepatosteatosis and liver damage. The expression of genes related to liver lipogenesis and inflammation was reduced in TRF mice, but the expression of genes involved in fatty acid ß-oxidation was increased. However, those beneficial effects of TRF were blunted in the FGF21 LKO mice. Moreover, TRF promoted improvements in insulin sensitivity and liver damage in DIO mice. Our data show that liver FGF21 signaling was involved in the effect of TRF on high-fat diet-induced fatty liver.

Work-Related Factors Associated With the Pelvic Floor Dysfunction Among a Sample of Female Nurses in China.

BACKGROUND: Female nurses are a high-risk group for pelvic floor dysfunction (PFD). Predictors of female nurses' PFD among work-related factors are not well known. The aim of this study was to investigate the prevalence of PFD and its association with workplace conditions among female nurses in China. METHODS: An online cross-sectional survey was conducted in May 2021. A sample of 380 registered nurses working in six tertiary hospitals in Nanjing, China participated. Data on individual characteristics, work-related factors, the Pelvic Floor Distress Inventory-20 and Pelvic Floor Impact Questionnaire-7 were used. FINDINGS: The overall prevalence of PFD among nurses was 83.9%, with 43.9% of participants experiencing pelvic organ prolapse, 66.6% experiencing anorectal dysfunction and 60.5% experiencing lower urinary tract symptoms. In terms of work-related factors, PFD was associated with heavy lifting, pushing, and carrying at work, delayed toileting at work and fluid intake. Female nurses with PFD reported lower quality of life (QoL) relative to nurses without PFD. CONCLUSIONS/APPLICATION TO PRACTICE: Our findings provide initial insights into workplace conditions that promote PFD among female nurses. Occupational health nurses should consider providing educational information for female workers who are potentially at risk for PFD and consider integrating screening of PFD into practice.

Inactivation of horseradish peroxidase with crotonic acid for reprobing of western blotting.

Inactivation of horseradish peroxidase (HRP) treatment is a conventional preference to stripping for sequential detections of different proteins of chemiluminescent western blotting (WB). However, little evidence exists on whether other chemical substances treatment can affects the biological activity of HRP during stripping and re-probing of WB blots. Here, we successfully develop 20% crotonic acid (CA) as an alternative to stripping to inhibit HRP used for sequential chemiluminescent WB on polyvinylidene difluoride (PVDF) and Nitrocellulose (NC) membrane. Moreover, NC blots incubation in CA (40 °C, 30min) allow us to perform three round HRP inhibition in sequential detections without losing transferred proteins and damaging membrane. Hence, the method will help us save time and valuable samples without the need to rerun gels.

Epidemiology of Tinea Capitis in Children in Beijing and Adjacent Regions, China: A 15-Year Retrospective Study.

BACKGROUND: Tinea capitis is the most common dermatophytosis in children. Due to many factors, the types of pathogenic fungi of tinea capitis vary all over the world, and the pathogenic fungi of tinea capitis may change over time even in the same region. OBJECTIVES: To investigated the epidemiological characteristics and pathogenic strains distribution of tinea capitis in children in Beijing and adjacent regions. Patients/Methods Through retrospective study and epidemiological analysis, we investigated the epidemiological characteristics of tinea capitis in children in Beijing and adjacent regions over 15 years. RESULTS: A total of 1739 children with tinea capitis were retrospectively investigated from January 2006 to December 2020, including 1100 boys and 639 girls. A total of 67.4% of tinea capitis patients were between 1 and 5 years of age. A decreasing trend in tinea capitis was observed before 2009, while for the following 12 years, the incidence rate of tinea capitis fluctuated little. Zoophilic isolates (primarily Microsporum canis) were responsible for 88.4% of tinea capitis. Males are at greater risk for M. canis infection (p = 0.02). CONCLUSION: Zoophilic species were responsible for approximately nine-tenth of the tinea capitis cases. The incidence of tinea capitis decreased before 2009.

The attenuated Mycoplasma bovis strain promotes apoptosis of bovine macrophages by upregulation of CHOP expression.

Mycoplasma bovis (M. bovis) is one of the major pathogens in the bovine respiratory disease complex, which includes pneumonia, mastitis, and arthritis and causes a great economic loss in the cattle industry. In China, a live-attenuated vaccine strain M. bovis P150 was obtained by a continuous culture of the wild-type strain M. bovis HB0801 (P1) in vitro for 150 passages. Using the infected bovine macrophage cell line BoMac, this work attempted to investigate the mechanism of P150 attenuation and protective immune response. To begin, we show that M. bovis P150 effectively triggered cytotoxicity and apoptosis in BoMac, although with lower intracellular survival than P1. The transcriptomes of BoMac after infection with M. bovis strains P1 and P150 were sequenced, and bioinformatic analysis identified 233 differentially expressed genes (DEGs), with 185 upregulated and 48 downregulated. Further Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analyses revealed that the majority of the DEGs were linked to CHOP complex, MAP kinase phosphatase activity and were involved in the IL-17 signaling pathway in immune response, MAPK signaling pathway in signal transduction, and p53 signaling pathway in cell growth and death. Among them, the level of C/EBP homologous protein (CHOP) was significantly upregulated in P150-infected BoMac compared to P1-infected cells at different time points, along with its upstream and downstream genes phosphorylated-PERK, phosphorylated-EIF2α, ATF4, and GADD45A increased in the PERK-dependent ER stress response. The role of CHOP in apoptosis was further verified by M. bovis-induced siCHOP knockdown in BoMac cells. The results showed that CHOP knockdown enhanced P150-induced apoptosis and dramatically increased the M. bovis P1 and P150 intracellular survival, particularly for P150. These data suggest that P150 infection upregulates CHOP expression, which can increase apoptosis and mediate a crosstalk between ER stress and apoptosis during infection, and hence, contribute to high cytotoxicity and low intracellular survival.