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Besides genome editing, CRISPR-Cas12a has recently been used for DNA detection applications with attomolar sensitivity but, to our knowledge, it has not been used for the detection of small molecules. Bacterial allosteric transcription factors (aTFs) have evolved to sense and respond sensitively to a variety of small molecules to benefit bacterial survival. By combining the single-stranded DNA cleavage ability of CRISPR-Cas12a and the competitive binding activities of aTFs for small molecules and double-stranded DNA, here we develop a simple, supersensitive, fast and high-throughput platform for the detection of small molecules, designated CaT-SMelor ( C RISPR-Cas12a- and aT F-mediated s mall m ol e cu l e detect or ). CaT-SMelor is successfully evaluated by detecting nanomolar levels of various small molecules, including uric acid and p -hydroxybenzoic acid among their structurally similar analogues. We also demonstrate that our CaT-SMelor directly measured the uric acid concentration in clinical human blood samples, indicating a great potential of CaT-SMelor in the detection of small molecules. Bacterial allosteric transcription factors can sense and respond to a variety of small molecules. Here the authors present CaT-SMelor which uses Cas12a and allosteric transcription factors to detect small molecules in the nanomolar range.

The nylon 12 (PA12) monomer ω-aminododecanoic acid (ω-AmDDA) could be synthesized from lauric acid (DDA) through multi-enzyme cascade transformation using engineered E. coli, with the P450 catalyzing terminal hydroxylation of DDA as a rate-limiting enzyme. Its activity is jointly determined by the heme domain and the reductase domain. To obtain a P450 mutant with higher activity, directed evolution was conducted using a colorimetric high-throughput screening (HTS) system with DDA as the real substrate. After two rounds of directed evolution, a positive double-site mutant (R14R/D629G) with 90.3% higher activity was obtained. Molecular docking analysis, kinetic parameter determination and protein electrophoresis suggested the improved soluble expression of P450 resulting from the synonymous mutation near the N-terminus and the shortened distance of the electron transfer between FMN and FAD caused by D629G mutation as the major reasons for activity improvement. The significantly increased kcat and unchanged Km provided further evidence for the increase in electron transfer efficiency. Considering the important role of heme in P450, its supply was strengthened by the metabolic engineering of the heme synthesis pathway. By combining P450-directed evolution and enhancing heme synthesis, 2.02 ± 0.03 g/L of ω-AmDDA was produced from 10 mM DDA, with a yield of 93.6%.

Mobile phone–based digital interventions have been shown to be a promising strategy for HIV prevention among men who have sex with men (MSM). This study aimed to evaluate the cost-effectiveness of a mobile phone–based digital intervention for HIV prevention among MSM in China from the perspective of a public health provider. The cost-effectiveness of the mobile phone–based digital intervention was estimated for a hypothetical cohort of 10,000 HIV-negative MSM who were followed for 1 year. A model was developed with China-specific data to project the clinical impact and cost-effectiveness of two mobile phone–based digital strategies for HIV prevention among MSM. The intervention group received an integrated behavioral intervention that included 1) individualized HIV infection risk assessment, 2) recommendation of centers testing for HIV and other STIs, 3) free online order of condoms and HIV and syphilis self-test kits and 4) educational materials about HIV/AIDS. The control group was only given educational materials about HIV/AIDS. Outcomes of interest were the number of HIV infections among MSM averted by the intervention, intervention costs, cost per HIV infection averted by the mobile phone–based digital intervention, and quality-adjusted life-years (QALYs). Univariate and multivariate sensitivity analyses were also conducted to examine the robustness of the results. It is estimated that the intervention can prevent 48 MSM from becoming infected with HIV and can save 480 QALYs. The cost of preventing 1 case of HIV infection was US 2599.87, and the cost-utility ratio was less than 0. Sensitivity analysis showed that the cost-effectiveness of the mobile phone–based digital intervention was mainly impacted by the average number of sexual behaviors with each sexual partner. Additionally, the higher the HIV prevalence among MSM, the greater the benefit of the intervention. Mobile phone–based digital interventions are a cost-effective HIV-prevention strategy for MSM and could be considered for promotion and application among high-risk MSM subgroups.

Osteosarcoma (OS) is a common type of bone tumor for which there has been limited therapeutic progress over the past three decades. The prevalence of transcriptional addiction in cancer cells emphasizes the biological significance and clinical relevance of super-enhancers. In this study, we found that Max-like protein X (MLX), a member of the Myc-MLX network, is driven by super-enhancers. Upregulation of MLX predicts a poor prognosis in osteosarcoma. Knockdown of MLX impairs growth and metastasis of osteosarcoma in vivo and in vitro. Transcriptomic sequencing has revealed that MLX is involved in various metabolic pathways (e.g., lipid metabolism) and can induce metabolic reprogramming. Furthermore, knockdown of MLX results in disturbed transport and storage of ferrous iron, leading to an increase in the level of cellular ferrous iron and subsequent induction of ferroptosis. Mechanistically, MLX regulates the glutamate/cystine antiporter SLC7A11 to promote extracellular cysteine uptake required for the biosynthesis of the essential antioxidant GSH, thereby detoxifying reactive oxygen species (ROS) and maintaining the redox balance of osteosarcoma cells. Importantly, sulfasalazine, an FDA-approved anti-inflammatory drug, can inhibit SLC7A11, disrupt redox balance, and induce massive ferroptosis, leading to impaired tumor growth in vivo. Taken together, this study reveals a novel mechanism in which super-enhancer-driven MLX positively regulates SLC7A11 to meet the alleviated demand for cystine and maintain the redox balance, highlighting the feasibility and clinical promise of targeting SLC7A11 in osteosarcoma.

Background Osteoporosis is a foremost public health challenge, especially with the global aging population. Both frailty and osteoporosis share many risk factors, although the relationship between them remains partially explored. This study aims to explore the correlation between varying frailty statuses and osteoporosis incidence. Methods Participants from the 2017–2018 NHANES were classified into three groups: frailty, prefrailty, and robust, based on the frailty phenotype. The correlation between frailty and osteoporosis prevalence was assessed using weighted multivariate logistic regression models. Causal relationship was verified by Mendelian randomization using frailty data from the U.K. Biobank and osteoporosis data from the FinnGen database. Proteomic analysis including associated protein screening and functional enrichments was performed based on data from the Icelandic cohort. Results The study group comprised 1814 participants. An increased incidence of osteoporosis was observed in older age and lower body mass index populations. A significant frailty–osteoporosis correlation (odds ratio [OR]: 1.37; 95% confidence interval [CI]: 1.14–1.64; p = 0.001) was indicated both in the crude model and after adjustments (OR: 1.23; 95% CI: 1.01–1.51; p = 0.039). The inverse variance weighting method observed a potential effect of frailty on osteoporosis risk (β/SE, 0.209/0.099; OR: 1.233; 95% CI: 1.014–1.499; p = 0.036). Thirteen frailty–osteoporosis‐associated proteins were found, and proteomic enrichment indicated oxidative stress‐related pathways as a hypothesis‐generating mechanism of frailty‐mediated osteoporosis. Conclusions Our findings suggest a potential causal association between frailty and osteoporosis, with risk exacerbating with the progression of frailty severity. Frailty potentially impacts the progression of osteoporosis through response to oxidative stress.

Liquid–liquid phase‐separated (LLPS) transcriptional factor assemblies at super‐enhancers (SEs) provide a conceptual framework for underlying transcriptional control in mammal cells. However, the mechanistic understanding of LLPS in aberrant transcription driven by dysregulation of SEs in human malignancies is still elusive. By integrating SE profiling and core regulatory circuitry (CRC) calling algorithm, the CRC of metastatic and chemo‐resistant osteosarcoma is delineated. CRC components, HOXB8 and FOSL1, produce dense and dynamic phase‐separated droplets in vitro and liquid‐like puncta in cell nuclei. Disruption of CRC phase separation decreases the chromatin accessibility in SE regions and inhibits the release of RNA polymerase II from the promoter of SE‐driven genes. Importantly, absence of CRC key component causes a reduction in osteosarcoma tumor growth and metastasis. Moreover, it is shown that CRC condensates can be specifically attenuated by the H3K27 demethylase inhibitor, GSK‐J4. Pharmacological inhibition of the CRC phase separation results in metastasis suppression and re‐sensitivity to chemotherapy drugs in patient‐derived xenograft model. Taken together, this study reveals a previously unknown mechanism that CRC factors formed LLPS condensates, and provides a phase separation‐based pharmacological strategy to target undruggable CRC components for the treatment of metastatic and chemo‐resistant osteosarcoma. Core regulatory circuitry (CRC) factors forms liquid–liquid phase‐separated condensates at super‐enhancers to regulate chromatin accessibility and oncogenic transcription. Pharmacological inhibition of the CRC phase separation by GSK‐J4 suppresses metastasis and chemoresistance in osteosarcoma patient‐derived xenograft model.

Background Tuberculosis (TB) infection poses a significant risk to patients undergoing hematopoietic stem cell transplantation (HSCT), particularly those with latent TB infection (LTBI). Despite the recognized vulnerability of these patients, data on TB prophylaxis and its outcomes in pediatric HSCT recipients remain limited. Methods We conducted a retrospective study of 714 pediatric HSCT recipients at Shenzhen Children’s Hospital from January 2018 to December 2021. Patients were categorized into LTBI high-risk and low-risk groups based on positive interferon-gamma release assay (IGRA) results and radiological findings indicative of prior TB infection. The high-risk group received isoniazid (INH) prophylaxis, while the low-risk group did not receive routine TB prophylaxis. Patient outcomes, including TB incidence, drug toxicity, and post-HSCT complications, were monitored over two years. Results The high-risk group comprised of 69 patients, and the low-risk group included 620 patients. No significant differences were observed between the groups regarding patient characteristics, HSCT type, or donor source. Over the follow-up period, no confirmed TB cases occurred in the high-risk group receiving INH prophylaxis, whereas one patient (0.31%) in the low-risk group developed TB. Mild hepatic toxicity (grade 1) was observed in 27.54% of patients in the high-risk group, with one case of grade 3 toxicity (1.45%) requiring INH discontinuation. No severe renal toxicity or fatal adverse events were reported. Post-HSCT complications included acute graft-versus-host disease (11.59%), chronic graft-versus-host disease (13.04%), and invasive fungal infections (4.35%), with no significant differences in outcomes between the groups. Full graft chimerism was achieved in 98.55% of patients, and no deaths occurred during the study period. Conclusions INH prophylaxis effectively prevented TB reactivation in LTBI high-risk pediatric HSCT recipients without significant adverse events. A risk-based stratification approach to TB prophylaxis is both safe and effective, minimizing unnecessary drug exposure while protecting vulnerable patients.

A parafoil delivery system has usually been used in the fields of military and civilian airdrop supply and aircraft recovery in recent years. However, since the altitude of the unpowered parafoil is monotonically decreasing, it is limited by the initial flight altitude. Thus, combining the multiple constraints, such as the ground obstacle avoidance and flight time, it puts forward a more stringent standard for the real-time performance of trajectory planning of the parafoil delivery system. Thus, to enhance the real-time performance, we propose a new parafoil trajectory planning method based on an improved twin delayed deep deterministic policy gradient. In this method, by pre-evaluating the value of the action, a scale of noise will be dynamically selected for improving the globality and randomness, especially for the actions with a low value. Furthermore, not like the traditional numerical computation algorithm, by building the planning model in advance, the deep reinforcement learning method does not recalculate the optimal flight trajectory of the system when the parafoil delivery system is launched at different initial positions. In this condition, the trajectory planning method of deep reinforcement learning has greatly improved in real-time performance. Finally, several groups of simulation data show that the trajectory planning theory in this paper is feasible and correct. Compared with the traditional twin delayed deep deterministic policy gradient and deep deterministic policy gradient, the landing accuracy and success rate of the proposed method are improved greatly.

Osteosarcoma, the most prevalent malignant bone tumor among adolescents, frequently exhibits limited responsiveness to immunotherapy, a challenge attributed to poorly understood underlying mechanisms. Here, we identify enhanced polyamine biosynthesis as a key driver of osteosarcoma progression and immunotherapy resistance. We show that osteosarcoma cell proliferation and tumor growth rely on polyamine availability and that disruption of polyamine synthesis significantly boosts the cytotoxic efficacy of TCR-engineered T cells against osteosarcoma cells. Mechanistically, we reveal that the knockdown of antizyme inhibitor 1 ( AZIN1 ) or suppression of polyamine production reduces MYC expression, leading to diminished tumor cell viability via the downregulation of cell cycle-related genes. Furthermore, reduced MYC levels are associated with changes in the expression of immunomodulatory cytokines and human leukocyte antigen molecules, pointing to a potential link with enhanced T-cell-mediated cytotoxicity. Collectively, our findings establish a pivotal role for the AZIN1-polyamine axis in osteosarcoma proliferation and immune evasion, and support the development of novel immunotherapeutic strategies targeting polyamine biosynthesis to combat this aggressive cancer.

Over the past decade, small RNA technologies have been proposed for improved control of parasitic worms. Although achievements have been made in the identification of target candidates and in the improvement of reverse genetic tools, few of those have been tested in domestic animals. In this work, crucial genes (i.e., daf-9/cyp-22a1 , bli-5 and HCON_00083600 ) involved in the developmental transition (i.e., activation, moulting and haem utilisation) from the infective L3 stage to the parasitic L4 stage of Haemonchus contortus (the barber’s pole worm commonly found in small ruminants) in vitro were identified and verified using RNA interference (RNAi) technologies during the adaptation to parasitism of this parasite in vivo. Silencing each of the daf-9/cyp-22a1 , bli-5 and HCON_00083600 genes in the infective larvae of H. contortus resulted in compromised larval development and viability in vitro, and silencing of either the daf-9/cyp-22a1 , bli-5 or HCON_00083600 gene led to a marked reduction in the faecal egg count and worm burden in sheep. In conclusion, the results demonstrate that genes involved in larval activation, moulting and haem utilisation of H. contortus are target candidates, and the application of RNAi technologies for better control of these and related parasitic nematodes is promising, preferably with an improved RNAi tool for efficient and long-lasting effects in host animals.