Preparation of (S)-epichlorohydrin using a novel halohydrin dehalogenase by selective conformation adjustment.

Chiral epichlorohydrin (ECH) is an attractive intermediate for chiral pharmaceuticals and chemicals preparation. The asymmetric synthesis of chiral ECH using 1,3-dicholoro-2-propanol (1,3-DCP) catalyzed by a haloalcohol dehalogenase (HHDH) was considered as a feasible approach. However, the reverse ring opening reaction caused low optical purity of chiral ECH, thus severely restricts the industrial application of HHDHs. In the present study, a novel selective conformation adjustment strategy was developed with an engineered HheCPS to regulate the kinetic parameters of the forward and reverse reactions, based on site saturation mutation and molecular simulation analysis. The HheCPS mutant E85P was constructed with a markable change in the conformation of (S)-ECH in the substrate pocket and a slight impact on the interaction between 1,3-DCP and the enzyme, which resulted in the kinetic deceleration of the reverse reactions. Compared with HheCPS, the catalytic efficiency (kcat(S)-ECH/Km(S)-ECH) of the reversed reaction dropped to 0.23-fold (from 0.13 to 0.03 mM-1 s-1), while the catalytic efficiency (kcat(1,3-DCP)/Km(1,3-DCP)) of the forward reaction only reduced from 0.83 to 0.71 mM-1 s-1. With 40 mM 1,3-DCP as substrate, HheCPS E85P catalyzed the synthesis of (S)-ECH with the yield up to 55.35% and the e.e. increased from 92.54 to >99%. Our work provided an effective approach for understanding the stereoselective catalytic mechanism as well as the green manufacturing of chiral epoxides.

Anti-neuraminidase immunity in the combat against influenza.

INTRODUCTION: Anti-neuraminidase (NA) immunity correlates with the protection against influenza virus infection in both human and animal models. The aim of this review is to better understand the mechanism of anti-NA immunity, and also to evaluate the approaches on developing NA-based influenza vaccines or enhancing immune responses against NA for current influenza vaccines. AREAS COVERED: In this review, the structure of influenza neuraminidase, the contribution of anti-NA immunity to protection, as well as the efforts and challenges of targeting the immune responses to NA were discussed. We also listed some of the newly discovered anti-NA monoclonal antibodies and discussed their contribution in therapeutic as well as the antigen design of a broadly protective NA vaccine. EXPERT OPINION: Targeting the immune response to both HA and NA may be critical for achieving the optimal protection since there are different mechanisms of HA and NA elicited protective immunity. Monoclonal antibodies (mAbs) that target the conserved protective lateral face or catalytic sites are effective therapeutics. The epitope discovery using monoclonal antibodies may benefit NA-based vaccine elicited broadly reactive antibody responses. Therefore, the potential for a vaccine that elicits cross-reactive antibodies against neuraminidase is a high priority for next-generation influenza vaccines.

Advancing kidney xenotransplantation with anesthesia and surgery - bridging preclinical and clinical frontiers challenges and prospects.

Xenotransplantation is emerging as a vital solution to the critical shortage of organs available for transplantation, significantly propelled by advancements in genetic engineering and the development of sophisticated immunosuppressive treatments. Specifically, the transplantation of kidneys from genetically engineered pigs into human patients has made significant progress, offering a potential clinical solution to the shortage of human kidney supply. Recent trials involving the transplantation of these modified porcine kidneys into deceased human bodies have underscored the practicality of this approach, advancing the field towards potential clinical applications. However, numerous challenges remain, especially in the domains of identifying suitable donor-recipient matches and formulating effective immunosuppressive protocols crucial for transplant success. Critical to advancing xenotransplantation into clinical settings are the nuanced considerations of anesthesia and surgical practices required for these complex procedures. The precise genetic modification of porcine kidneys marks a significant leap in addressing the biological and immunological hurdles that have traditionally challenged xenotransplantation. Yet, the success of these transplants hinges on the process of meticulously matching these organs with human recipients, which demands thorough understanding of immunological compatibility, the risk of organ rejection, and the prevention of zoonotic disease transmission. In parallel, the development and optimization of immunosuppressive protocols are imperative to mitigate rejection risks while minimizing side effects, necessitating innovative approaches in both pharmacology and clinical practices. Furthermore, the post-operative care of recipients, encompassing vigilant monitoring for signs of organ rejection, infectious disease surveillance, and psychological support, is crucial for ensuring post-transplant life quality. This comprehensive care highlights the importance of a multidisciplinary approach involving transplant surgeons, anesthesiologists, immunologists, infectiologists and psychiatrists. The integration of anesthesia and surgical expertise is particularly vital, ensuring the best possible outcomes of those patients undergoing these novel transplants, through safe procedural practices. As xenotransplantation moving closer to clinical reality, establishing consensus guidelines on various aspects, including donor-recipient selection, immunosuppression, as well as surgical and anesthetic management of these transplants, is essential. Addressing these challenges through rigorous research and collective collaboration will be the key, not only to navigate the ethical, medical, and logistical complexities of introducing kidney xenotransplantation into mainstream clinical practice, but also itself marks a new era in organ transplantation.

Modeling protective action decision-making in earthquakes by using explainable machine learning and video data.

Earthquakes pose substantial threats to communities worldwide. Understanding how people respond to the fast-changing environment during earthquakes is crucial for reducing risks and saving lives. This study aims to study people's protective action decision-making in earthquakes by leveraging explainable machine learning and video data. Specifically, this study first collected real-world CCTV footage and video postings from social media platforms, and then identified and annotated changes in the environment and people's behavioral responses during the M7.1 2018 Anchorage earthquake. By using the fully annotated video data, we applied XGBoost, a widely-used machine learning method, to model and forecast people's protective actions (e.g., drop and cover, hold on, and evacuate) during the earthquake. Then, explainable machine learning techniques were used to reveal the complex, nonlinear relationships between different factors and people's choices of protective actions. Modeling results confirm that social and environmental cues played critical roles in affecting the probability of different protective actions. Certain factors, such as the earthquake shaking intensity and number of people shown in the environment, displayed evident nonlinear relationships with the probability of choosing to evacuate. These findings can help emergency managers and policymakers design more effective protective action recommendations during earthquakes.

"Access to pharmacy services is difficult in China": a qualitative study from the perspective of transplant recipients to explore their expectations.

PURPOSE: To gain an in-depth and comprehensive understanding of Chinese organ transplant recipients' perceptions, expectations, and suggestions of pharmacy services to hospital pharmacists. METHODS: This qualitative study was conducted in central China, from February to December 2020. Participants were collected with a purposive and snowball sampling method. Focus group discussions were conducted with organ transplant recipients and content analysis was applied to identify themes and subthemes. RESULTS: 21 recipients participated in the qualitative study. Four themes and thirteen subthemes were identified: (1) perceptions of clinical pharmacists and pharmacy services; (2) expectations for pharmacy service content; (3) expectations for pharmacy service form; and (4) difficulties as a special group. CONCLUSION: The pharmacy services provided by Chinese healthcare institutions are inadequate to meet the needs of organ transplant recipients. However, the acceptance and expectation of pharmacy services by transplant recipients are high. Therefore, China should learn from the experience of developed countries and focus on the actual needs of patients to establish a better pharmacy service system for organ transplantation.

Multi-COBRA hemagglutinin formulated with cGAMP microparticles elicit protective immune responses against influenza viruses.

Influenza viruses cause a common respiratory disease known as influenza. In humans, seasonal influenza viruses can lead to epidemics, with avian influenza viruses of particular concern because they can infect multiple species and lead to unpredictable and severe disease. Therefore, there is an urgent need for a universal influenza vaccine that provides protection against seasonal and pre-pandemic influenza virus strains. The cyclic GMP-AMP (cGAMP) is a promising adjuvant for subunit vaccines that promotes type I interferons production through the stimulator of interferon genes (STING) pathway. The encapsulation of cGAMP in acetalated dextran (Ace-DEX) microparticles (MPs) enhances its intracellular delivery. In this study, the Computationally Optimized Broadly Reactive Antigen (COBRA) methodology was used to generate H1, H3, and H5 vaccine candidates. Monovalent and multivalent COBRA HA vaccines formulated with cGAMP Ace-DEX MPs were evaluated in a mouse model for antibody responses and protection against viral challenge. Serological analysis showed that cGAMP MPs adjuvanted monovalent and multivalent COBRA vaccines elicited robust antigen-specific antibody responses after a prime-boost vaccination and antibody titers were further enhanced after second boost. Compared to COBRA vaccine groups with no adjuvant or blank MPs, the cGAMP MPs enhanced HAI antibody responses against COBRA vaccination. The HAI antibody titers were not significantly different between cGAMP MPs adjuvanted monovalent and multivalent COBRA vaccine groups for most of the viruses tested in panels. The cGAMP MPs adjuvanted COBRA vaccines groups had higher antigen-specific IgG2a binding titers than the COBRA vaccine groups with no adjuvant or blank MPs. The COBRA vaccines formulated with cGAMP MPs mitigated disease caused by influenza viral challenge and decreased pulmonary viral titers in mice. Therefore, the formulation of COBRA vaccines plus cGAMP MPs is a promising universal influenza vaccine that elicits protective immune responses against human seasonal and pre-pandemic strains.

Structural and in vivo-in vitro myocardial injury protection features of two novel polysaccharides from Allium macrostemon Bunge and Allium chinense G. Don.

This study aimed to investigate the structural characteristics, in vivo antiatherosclerosis activity, and in vitro myocardial injury protection effects of polysaccharides from Allium macrostemon Bunge and Allium chinense G. Don. Thus, crude polysaccharides of Allium macrostemon Bunge and Allium chinense G. Don significantly reduced serum lipid levels, improved cardiac myocyte morphology and arrangement, and relieved the development of myocardial fibrosis. Meanwhile, the lesion areas of the aorta and aortic valve had evident visual improvements. Furthermore, two main novel purified polysaccharides, namely, AMB-1 and ACGD-1, were isolated and characterized from crude Allium macrostemon Bunge and Allium chinense G. Don fractions, respectively. The purified polysaccharides mainly consisted of fructose and glucose and had molecular weights of 25.22 and 19.53 kDa, respectively. In addition, Fourier transform infrared spectroscopy, methylation, and nuclear magnetic resonance data revealed the primary structures of the AMB1 (or ACGD1) backbone with branched side chains. Scanning electron microscope analysis showed that the purified polysaccharides were both piled together in a lamellar or clastic form with a smooth surface along with linear or irregular bulges. Moreover, the purified polysaccharides both showed nontoxicity on H9c2 cells and effectively dropped hypoxia/reoxygenation-induced apoptosis by the BCL-2/BAX pathway. Overall, the characterization of the structural properties and in vivo and in vitro myocardial injury protection effects of Allium macrostemon Bunge and Allium chinense G. Don polysaccharides enriched our understanding of their nutritional and medicinal values. To the best of our knowledge, this is the first study on the structural characteristics and bioactivities of Allium chinense G. Don polysaccharides.

Activities of BiFeO3/carbon-dots catalysts in piezo-photocatalytic degradation of ciprofloxacin upon light/ultrasonic excitation.

Designing catalysts that can effectively make use of renewable energy benefits to solve the current challenges of environmental pollution and increasing energy demands. Piezo-photocatalysis that can utilize solar energy and natural vibration-energy has emerged as a "green" technique. In this work, we fabricated BiFeO3/C nano composites that can harvest solar and vibration energies and degrade organic pollutants. The incorporated carbon quantum dots bring about more efficient visible light absorbance and separation of photoinduced electron-hole pairs. The piezoelectric polarization further suppresses the recombination of photoinduced electron-hole pairs. The catalysts own higher reaction rates in piezo-photocatalysis and the BiFeO3/C-0.12 shows the highest degradation efficiency (k-value of 0.0835 min-1).

Enhanced EPR effects by tumour stromal cell mimicking nanoplatform on invasive pituitary adenoma.

Rapid advances in nanomedicine have enabled potential applications in cancer therapy. The enhanced permeability and retention (EPR) effect is the primary rationale for the passive targeting of nanoparticles in oncology. However, growing evidence indicates that the accumulation of nanomaterials via the EPR effect could be more efficient. Inspired by our clinical observation of the Gap Junction connecpion between folliculostellate cells and pituitary adenoma cells, we designed a novel drug delivery system that targets tumours by coating folliculostellate cell (FS) membranes onto PLGA nanoparticles (NPs). The resulting FSNPs, inheriting membrane proteins from the folliculostellate cell membrane, significantly enhanced the EPR effect compared to nanoparticles without cancer cell membranes. We further demonstrated that mitotane encapsulation improved the therapeutic efficacy of mitotane in both heterotopic and orthotopic pituitary adenoma models. Owing to its significant efficacy, our FS cell membrane-coated nanoplatforms has the potential to be translated into clinical applications for the treatment of invasive pituitary adenoma.

Exploring the problems and coping strategies of pharmacy internship in large general hospitals in China: from the perspective of preceptors.

OBJECTIVE: The role of the Hospital Pharmacy Preceptor (HPP) is pivotal in upholding the excellence of experiential training and fostering the professional growth of pharmacy interns. However, there is a lack of studies that provide an overview of pharmacy internships from the perspective of HPP. This study explores the experience and expectations of HPPs regarding existing problems and possible coping strategies in intern teaching. METHODS: This is a qualitative study that was conducted through individual interviews and focus group discussions. HPPs were invited as participants from large-scale tertiary hospitals in representative provinces of mainland China. Interview and focus group discussion data were analyzed using thematic analysis to see emerging themes from the data. Nvivo 12 was utilized for data management and processing. RESULTS: Eight individual interviews and two focus group discussions were conducted, involving 14 HPPs as participants. Upon the examination of the interviews and focus group data, four themes were summarized regarding HPPs' perceptions: 1) current presenting problems; 2) possible coping strategies; 3) something HPPs should do; 4) something interns should do. CONCLUSION: This study found that from the HPPs' perspective, the hospital-based pharmacy internship still has some problems from policy to practice, which need to be addressed by the joint efforts of the state, schools, internship bases, pharmacy preceptors, and students.

Psychological Status, Influencing Factors and Intervention Countermeasures of Hospital Pharmacists in Extreme Working Environments in the Post-Pandemic Era--An Embedded Mixed Study.

Objective: The study explores the psychological state and related influences of hospital pharmacists enclosed in extreme work environments in the post-epidemic era, and also explores potential measures to alleviate negative emotions. Methods: An embedded mixed research methodology was used. In the qualitative research phase, semi-structured interviews were carried out with 30 pharmacists consistently confined to their work environments. The data were managed and analyzed using NVivo12 software. In the quantitative research phase, 146 pharmacists with experience in extreme work environments were selected, and the data were collected through questionnaires (GAD-7 and CD-RISC-25) and self-administered questions generated during the qualitative phase. The Shapiro-Wilk test was utilized to assess data normality. Spearman correlation was conducted to evaluate correlations among self-designed questions, resilience, and anxiety. Results: The results from interviews with 30 pharmacists revealed four factors influencing the psychological state of pharmacists in the post-epidemic era: personal factors, interpersonal relationships, environmental factors, and policy and public opinion. Mitigation measures for negative emotions encompass material security, life adjustment, epidemic prevention policy, public opinion information, and organizational management. The results of a quantitative study of 146 pharmacists showed that only 1% had severe anxiety, but the psychological resilience scores were generally low, and 62% had poor psychological resilience, with scores below 73. Simultaneously, it was observed that, except religious beliefs, factors influencing psychological status in extreme work environments were significantly negatively correlated with personal anxiety levels and significantly positively correlated with psychological resilience. Conclusion: Our study holds significance in unraveling the psychological aspects of pharmacists as healthcare workers. It also offers insights into how healthcare organizations respond to the negative emotions experienced by healthcare workers in emergencies or extreme environments.

Organ donation decision-making in ICU patients: from the perspectives of organ coordinators and physicians in China - a qualitative study.

OBJECTIVES: Intensive care unit (ICU) dying patients are the most important source of organ donation. This study explores the reasons affecting organ donation in the Chinese sociocultural context from the perspectives of coordinators and physicians, and further seeks countermeasures to alleviate the shortage of organs. DESIGN AND SETTING: Semistructured interviews conducted in a large tertiary hospital in China. PARTICIPANTS AND METHOD: 15 respondents (including 8 organ coordinators and 7 ICU physicians) were interviewed. Participants were invited to describe the factors that influence organ donation and the underlying reasons behind it. Bronfenbrenner's socioecological system model was used as theoretical support to construct a theoretical model of the factors influencing organ donation. Respondents participated in semistructured qualitative interviews that were audio-recorded and transcribed. The relevant data were analysed using thematic analysis. RESULTS: Four themes that influenced organ donation were identified including the influence of the deceased person's attributes, immediate family members, surrounding people and the environment, and the social-level factors. In addition, we obtained four strategies from the interviews to improve the organ shortage to ameliorate the current supply-demand imbalance in organ donation. These include multilevel publicity, relevant policy support, increasing other forms of supply and reducing organ demand. CONCLUSIONS: Factors affecting organ donation after the death of a Chinese citizen include the personal characteristics of the donor, the decisions of family members such as immediate family members and the indirect influence of surrounding people such as collateral family members, in addition to factors related to the humanistic environment, religious beliefs and social opinion.

Isomerase and epimerase: overview and practical application in production of functional sugars.

The biosynthesis of functional sugars has gained significant attention due to their potential health benefits and increasing demand in the food industry. Enzymatic synthesis has emerged as a promising approach, offering high catalytic efficiency, chemoselectivity, and stereoselectivity. However, challenges such as poor thermostability, low catalytic efficiency, and food safety concerns have limited the commercial production of functional sugars. Protein engineering, including directed evolution and rational design, has shown promise in overcoming these barriers and improving biocatalysts for large-scale production. Furthermore, enzyme immobilization has proven effective in reducing costs and facilitating the production of functional sugars. To ensure food safety, the use of food-grade expression systems has been explored. However, downstream technologies, including separation, purification, and crystallization, still pose challenges in terms of efficiency and cost-effectiveness. Addressing these challenges is crucial to optimize the overall production process. Despite the obstacles, the future outlook for functional sugars is promising, driven by increasing awareness of their health benefits and continuous technological advancements. With further research and technological breakthroughs, industrial-scale production of functional sugars through biosynthesis will become a reality, leading to their widespread incorporation in various industries and products.

Designing a novel (R)-ω-transaminase for asymmetric synthesis of sitagliptin intermediate via motif swapping and semi-rational design.

The application of (R)-ω-transaminases as biocatalysts for chiral amine synthesis has been hampered by inadequate stereoselectivity and narrow substrate spectrum. Herein, an effective evolution strategy for (R)-ω-transaminase designing for the asymmetric synthesis of sitagliptin intermediate is presented. Since natural transaminases lack activity toward bulky prositagliptin ketone, transaminase scaffolds with catalytic machinery and activity toward the truncated prositagliptin ketone were firstly screened based on substrate walking principle. A transaminase chimera was established synchronously conferring catalytic activity and (R)-selectivity toward prositagliptin ketone through motif swapping, followed by stepwise evolution. The process resulted in a "best" engineered variant MwTAM8, which exhibited 79.2-fold higher activity than the chimeric scaffold MwTAMc. Structural analysis revealed that the heightened activity is mainly due to the enlarged and adaptive substrate pocket and tunnel. The novel (R)-transaminase exhibited unsatisfied industrial operation stability, which is expected to further modify the protein to enhance its tolerance to temperature, pH, and organic solvents to meet sustainable industrial demands. This study underscores a useful evolution strategy of engineering biocatalysts to confer new properties and functions on enzymes for synthesizing high-value drug intermediates.

Efficient biosynthesis of Vibegron intermediate using a novel carbonyl reductase based on molecular modification of hydrogen bonding network regulation.

Vibegron is a novel, potent, highly selective ß3-adrenergic receptor agonist for the treatment of overactive bladder with higher therapeutic capacity and lower side effects. Methyl(2S,3R)-2-((tert-butoxycarbonyl)amino)-3-hydroxy-3-phenylpropanoate ((2S,3R)-aminohydroxy ester) is a key chiral intermediate for the synthesis of Vibegron. A novel carbonyl reductase from Exiguobacterium sp. s126 (EaSDR6) was isolated using data mining technology from GenBank database with preferable catalytic activity. Hydrogen bond network regulation was performed using site-directed saturation mutagenesis and combination mutagenesis. The mutant EaSDR6A138L/S193A was obtained with the activity improvement by 4.58 folds compared with the wild type EaSDR6. The Km of EaSDR6A138L/S193A was decreased from 1.57 mM to 0.67 mM, kcat was increased by 2.17 folds, and the overall catalytic efficiency kcat/Km was increased by 5.07 folds. The organic-aqueous biphasic bioreaction system for the asymmetric synthesis of (2S,3R)-aminohydroxy ester was constructed for the first time. Under the substrate concentration of 150 g/L, the yield of (2S,3R)-aminohydroxy ester was > 99.99%, the e.e. was > 99.99%, and the spatiotemporal yield was 1.55 g/(L·h·g DCW) after 12 h reaction. While the substrate concentration was increased to 200 g/L and the reaction lasted for 36 h, the yield of (2S,3R)-aminohydroxy ester was > 99.99%, the e.e. was > 99.99% and the spatiotemporal yield was 1.05 g/(L·h·g DCW). The substrate concentration and spatiotemporal yield were higher than ever reported.

LncRNA SOCS2-AS1 promotes the progression of papillary thyroid cancer by destabilizing p53 protein.

Long noncoding RNAs (lncRNAs) have been shown to contribute to tumorigenesis and cancer progression. However, neither the dysregulation nor the functions of anti-sense lncRNAs in papillary thyroid carcinoma (PTC) have been exhaustively studied. In this study, we accessed The Cancer Genome Atlas (TCGA) database and discovered that the natural antisense lncRNA SOCS2-AS1 is highly expressed in PTC and that patients with a higher level of SOCS2-AS1 had a poor prognosis. Furthermore, loss- and gain-function assays demonstrated that SOCS2-AS1 promotes PTC cell proliferation and growth both in vitro and in vivo. In addition, we demonstrated that SOCS2-AS1 regulates the rate of fatty acid oxidation (FAO) in PTC cells. Analysis of the mechanism revealed that SOCS2-AS1 binds to p53 and controls its stability in PTC cell lines. Overall, our findings showed that the natural antisense lncRNA SOCS2-AS1 stimulates the degradation of p53 and enhances PTC cell proliferation and the FAO rate.

Genetic structure and characteristics of Tibetan chickens.

Tibetan chicken is one of the most common and widely distributed highland breeds, and is often used as a model organism for understanding genetic adaptation to extreme environments in Tibet. Despite its apparent geographical diversity and large variations in plumage patterns, the genetic differences within breed were not accounted for in most studies and have not been systematically investigated. In order to reveal and genetically differentiate the current existing TBC sub-populations that might have major implications for genomic research in TBCs, we systematically evaluated the population structure and demography of current TBC populations. Based on 344 whole-genome sequenced birds including 115 Tibetan chickens that were mostly sampled from family-farms across Tibet, we revealed a clear separation of Tibetan chickens into 4 sub-populations that broadly aligns with their geographical distribution. Moreover, population structure, population size dynamics, and the extent of admixture jointly suggest complex demographic histories of these sub-populations, including possible multiple origins, inbreeding, and introgressions. While most of the candidate selected regions found between the TBC sub-populations and Red Jungle fowls were nonoverlapping, 2 genes RYR2 and CAMK2D were revealed as strong selection candidates in all 4 sub-populations. These 2 previously identified high altitude associated genes indicated that the sub-populations responded to similar selection pressures in an independent but functionally similar fashion. Our results demonstrate robust population structure in Tibetan chickens that will help inform future genetic analyses on chickens and other domestic animals alike in Tibet, recommending thoughtful experimental design.

Bio-inspired self-assembled bacteriochlorin nanoparticles for superior visualization and photothermal ablation of tumors.

BACKGROUND: Although hyperthermia-based photothermal therapy (PTT) has achieved great success in the battle against malignant tumors, various commonly used photothermal sensitizers still suffer from non-selective tumor accumulation, limited photothermal conversion efficiency, potential toxicity and side effects, as well as complex and low cost-effective preparation process. Therefore, novel photothermal sensitizers are urgently required. The well-organized self-assembling of natural bacteriochlorophylls with superior photothermal property may provide an interesting option for the engineering of ideal PTS. METHODS: Inspired by the self-assembly peripheral light-harvesting antennas of natural bacteriochlorin in microorganisms, a biomimetic light-harvesting nanosystem (Nano-Bc) was developed via bacteriochlorophylls self-arranging in aqueous phase. The characterization of Nano-Bc were measured using DLS, TEM, UV-vis-near-infrared spectroscopy and preclinical PA imaging system. The cytotoxicity of Nano-Bc was quantitatively evaluated via a standard MTT assay using mouse breast cancer 4T1 cells, and the in vivo photothermal eradication of tumor was investigated in the 4T1 breast tumor-bearing mouse model. RESULTS: The obtained bacteriochlorin nanoparticles (Nano-Bc) exhibited ultra-high photothermal performance within the biological transparent window, showing superior heating capacity compared to commonly used photothermal sensitizers of organic dye indocyanine green and inorganic gold nanorods. Guiding by the inherent photoacoustic imaging of Nano-Bc, complete tumor elimination in vitro and vivo was evidenced upon laser irradiation. CONCLUSION: The green and facile preparation, ultra-high photothermal effect in the transparent window, excellent photoacoustic imaging capacity, and great biosafety prompt, the bio-inspired Nano-Bc as a promising theranostic platform against cancer in the areas of healthcare.

Testis-specific knockout of Kdm2a reveals nonessential roles in male fertility but partially compromises spermatogenesis.

Lysine-specific histone demethylase 2 (Kdm2a) is a regulatory factor of histone modifications that participates in gametogenesis and embryonic development. The mis-regulation of Kdm2a can lead to aberrant gene expression, thereby contributing to abnormal cell proliferation, differentiation, apoptosis, and tumorigenesis. However, due to the potential confounding effects that are secondary to the loss of Kdm2a function from the soma in existing whole-animal mutants, the in vivo function of Kdm2a in spermatogenesis for male fertility remains unknown. Herein, we focus on exploring the spatiotemporal expression profile and biological functions of Kdm2a in the spermatogenesis and fertility of male mice. A testis-specific knockout Kdm2a model (Kdm2a cKO) was established by using the Stra8-Cre/loxP recombinase system to explore the roles of Kdm2a in male fertility. Our results showed that Kdm2a was ubiquitously expressed and dynamically distributed in multiple tissues and cell types in the testis of mice. Surprisingly, Kdm2a-deficient adult males were completely fertile and comparable with their control (Kdm2aflox/flox) counterparts. Despite the significantly reduced total number of sperm and density of seminiferous tubules in Kdm2a cKO testis accompanied by the degeneration of spermatogenesis, the fertilization ability and embryonic developmental competence of the Kdm2a cKO were comparable with those of their control littermates, suggesting that Kdm2a disruption did not markedly affect male fertility, at least during younger ages. Furthermore, Kdm2a homozygous mutants exhibited a lower total number and motility of sperm than the control group and showed notably affected serum 17ß-estradiol concentration. Interestingly, the transcriptome sequencing revealed that the loss of Kdm2a remarkably upregulated the expression level of Kdm2b. This effect, in turn, may induce compensative effects in the case of Kdm2a deficiency to maintain normal male reproduction. Together, our results reveal that Kdm2a shows spatiotemporal expression during testicular development and that its loss is insufficient to compromise the production of spermatozoa completely. The homologous Kdm2b gene might compensate for the loss of Kdm2a. Our work provides a novel Kdm2a cKO mouse allowing for the efficient deletion of Kdm2a in a testis-specific manner, and further investigated the biological function of Kdm2a and the compensatory effects of Kdm2b. Our study will advance our understanding of underlying mechanisms in spermatogenesis and male fertility.

Aberrant m5C hypermethylation mediates intrinsic resistance to gefitinib through NSUN2/YBX1/QSOX1 axis in EGFR-mutant non-small-cell lung cancer.

BACKGROUND: RNA 5-methylcytosine (m5C) modification plays critical roles in the pathogenesis of various tumors. However, the function and molecular mechanism of RNA m5C modification in tumor drug resistance remain unclear. METHODS: The correlation between RNA m5C methylation, m5C writer NOP2/Sun RNA methyltransferase family member 2 (NSUN2) and EGFR-TKIs resistance was determined in non-small-cell lung cancer (NSCLC) cell lines and patient samples. The effects of NSUN2 on EGFR-TKIs resistance were investigated by gain- and loss-of-function assays in vitro and in vivo. RNA-sequencing (RNA-seq), RNA bisulfite sequencing (RNA-BisSeq) and m5C methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) were performed to identify the target gene of NSUN2 involved in EGFR-TKIs resistance. Furthermore, the regulatory mechanism of NSUN2 modulating the target gene expression was investigated by functional rescue and puromycin incorporation assays. RESULTS: RNA m5C hypermethylation and NSUN2 were significantly correlated with intrinsic resistance to EGFR-TKIs. Overexpression of NSUN2 resulted in gefitinib resistance and tumor recurrence, while genetic inhibition of NSUN2 led to tumor regression and overcame intrinsic resistance to gefitinib in vitro and in vivo. Integrated RNA-seq and m5C-BisSeq analyses identified quiescin sulfhydryl oxidase 1 (QSOX1) as a potential target of aberrant m5C modification. NSUN2 methylated QSOX1 coding sequence region, leading to enhanced QSOX1 translation through m5C reader Y-box binding protein 1 (YBX1). CONCLUSIONS: Our study reveals a critical function of aberrant RNA m5C modification via the NSUN2-YBX1-QSOX1 axis in mediating intrinsic resistance to gefitinib in EGFR-mutant NSCLC.