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Nature Communications Feb 2024Replication fork reversal, a critical protective mechanism against replication stress in higher eukaryotic cells, is orchestrated via a series of coordinated enzymatic...
Replication fork reversal, a critical protective mechanism against replication stress in higher eukaryotic cells, is orchestrated via a series of coordinated enzymatic reactions. The Bloom syndrome gene product, BLM, a member of the highly conserved RecQ helicase family, is implicated in this process, yet its precise regulation and role remain poorly understood. In this study, we demonstrate that the GCFC domain-containing protein TFIP11 forms a complex with the BLM helicase. TFIP11 exhibits a preference for binding to DNA substrates that mimic the structure generated at stalled replication forks. Loss of either TFIP11 or BLM leads to the accumulation of the other protein at stalled forks. This abnormal accumulation, in turn, impairs RAD51-mediated fork reversal and slowing, sensitizes cells to replication stress-inducing agents, and enhances chromosomal instability. These findings reveal a previously unidentified regulatory mechanism that modulates the activities of BLM and RAD51 at stalled forks, thereby impacting genome integrity.
Topics: Humans; DNA Replication; DNA Damage Tolerance; RecQ Helicases; DNA; Proteins; Genomic Instability; Rad51 Recombinase; RNA Splicing Factors
PubMed: 38341452
DOI: 10.1038/s41467-024-45684-3 -
BioRxiv : the Preprint Server For... Dec 2023Bacterial vaginosis (BV), a common syndrome characterized by -deficient vaginal microbiota, is associated with adverse health outcomes. BV often recurs after standard...
Bacterial vaginosis (BV), a common syndrome characterized by -deficient vaginal microbiota, is associated with adverse health outcomes. BV often recurs after standard antibiotic therapy in part because antibiotics promote microbiota dominance by instead of , which has more beneficial health associations. Strategies to promote and inhibit are thus needed. We show that oleic acid (OA) and similar long-chain fatty acids simultaneously inhibit and enhance growth. These phenotypes require OA-inducible genes conserved in and related species, including an oleate hydratase () and putative fatty acid efflux pump (). FarE mediates OA resistance, while OhyA is robustly active in the human vaginal microbiota and sequesters OA in a derivative form that only -harboring organisms can exploit. Finally, OA promotes dominance more effectively than antibiotics in an model of BV, suggesting a novel approach for treatment.
PubMed: 38234804
DOI: 10.1101/2023.12.30.573720 -
The World Journal of Men's Health Apr 2024Non-obstructive azoospermia (NOA) is a common, but complex problem, with multiple therapeutic options and a lack of clear guidelines. Hence, there is considerable...
Global Practice Patterns and Variations in the Medical and Surgical Management of Non-Obstructive Azoospermia: Results of a World-Wide Survey, Guidelines and Expert Recommendations.
PURPOSE
Non-obstructive azoospermia (NOA) is a common, but complex problem, with multiple therapeutic options and a lack of clear guidelines. Hence, there is considerable controversy and marked variation in the management of NOA. This survey evaluates contemporary global practices related to medical and surgical management for patients with NOA.
MATERIALS AND METHODS
A 56-question online survey covering various aspects of the evaluation and management of NOA was sent to specialists around the globe. This paper analyzes the results of the second half of the survey dealing with the management of NOA. Results have been compared to current guidelines, and expert recommendations have been provided using a Delphi process.
RESULTS
Participants from 49 countries submitted 336 valid responses. Hormonal therapy for 3 to 6 months was suggested before surgical sperm retrieval (SSR) by 29.6% and 23.6% of participants for normogonadotropic hypogonadism and hypergonadotropic hypogonadism respectively. The SSR rate was reported as 50.0% by 26.0% to 50.0% of participants. Interestingly, 46.0% reported successful SSR in <10% of men with Klinefelter syndrome and 41.3% routinely recommended preimplantation genetic testing. Varicocele repair prior to SSR is recommended by 57.7%. Half of the respondents (57.4%) reported using ultrasound to identify the most vascularized areas in the testis for SSR. One-third proceed directly to microdissection testicular sperm extraction (mTESE) in every case of NOA while others use a staged approach. After a failed conventional TESE, 23.8% wait for 3 months, while 33.1% wait for 6 months before proceeding to mTESE. The cut-off of follicle-stimulating hormone for positive SSR was reported to be 12-19 IU/mL by 22.5% of participants and 20-40 IU/mL by 27.8%, while 31.8% reported no upper limit.
CONCLUSIONS
This is the largest survey to date on the real-world medical and surgical management of NOA by reproductive experts. It demonstrates a diverse practice pattern and highlights the need for evidence-based international consensus guidelines.
PubMed: 38606867
DOI: 10.5534/wjmh.230339 -
The Journal of Clinical Investigation May 2024The gut microbiota is an integral part of the human metaorganism that is required to shape physiologic host immune responses including host defense against pathogens....
The gut microbiota is an integral part of the human metaorganism that is required to shape physiologic host immune responses including host defense against pathogens. Disease-associated gut dysbiosis has been characterized by blooms of pathobionts, which are bacterial species that can drive disease under certain conditions. Pathobionts like Enterobacteriaceae often bloom during flares of inflammatory bowel disease (IBD) and are causally linked with IBD in murine models. In this issue of the JCI, Hecht and colleagues investigated how simple carbohydrates are causally linked to the bloom of the gut pathobiont Klebsiella pneumoniae, which belong to the Enterobacteriaceae family. Notably, the presence of fiber reduced the dissemination of K. pneumoniae into the blood and liver in a colitis model. Their findings provide a diet-related mechanism for gut dysbiosis, which has implications in the management of IBD and other conditions in which gut dysbiosis is an underlying factor.
Topics: Humans; Dysbiosis; Animals; Gastrointestinal Microbiome; Klebsiella pneumoniae; Inflammatory Bowel Diseases; Mice; Dietary Carbohydrates; Klebsiella Infections; Colitis; Dietary Fiber
PubMed: 38690730
DOI: 10.1172/JCI180001 -
The Journal of Pediatrics Dec 2023To describe the clinical presentation, management, and outcomes of Kawasaki disease (KD) in Latin America and to evaluate early prognostic indicators of coronary artery... (Observational Study)
Observational Study
OBJECTIVES
To describe the clinical presentation, management, and outcomes of Kawasaki disease (KD) in Latin America and to evaluate early prognostic indicators of coronary artery aneurysm (CAA).
STUDY DESIGN
An observational KD registry-based study was conducted in 64 participating pediatric centers across 19 Latin American countries retrospectively between January 1, 2009, and December 31, 2013, and prospectively from June 1, 2014, to May 31, 2017. Demographic and initial clinical and laboratory data were collected. Logistic regression incorporating clinical factors and maximum coronary artery z-score at initial presentation (between 10 days before and 5 days after intravenous immunoglobulin [IVIG]) was used to develop a prognostic model for CAA during follow-up (>5 days after IVIG).
RESULTS
Of 1853 patients with KD, delayed admission (>10 days after fever onset) occurred in 16%, 25% had incomplete KD, and 11% were resistant to IVIG. Among 671 subjects with reported coronary artery z-score during follow-up (median: 79 days; IQR: 36, 186), 21% had CAA, including 4% with giant aneurysms. A simple prognostic model utilizing only a maximum coronary artery z-score ≥2.5 at initial presentation was optimal to predict CAA during follow-up (area under the curve: 0.84; 95% CI: 0.80, 0.88).
CONCLUSION
From our Latin American population, coronary artery z-score ≥2.5 at initial presentation was the most important prognostic factor preceding CAA during follow-up. These results highlight the importance of early echocardiography during the initial presentation of KD.
Topics: Child; Humans; Coronary Aneurysm; Immunoglobulins, Intravenous; Latin America; Mucocutaneous Lymph Node Syndrome; Retrospective Studies
PubMed: 36775190
DOI: 10.1016/j.jpeds.2023.02.001 -
BioRxiv : the Preprint Server For... Apr 2024Bloom Syndrome helicase (Blm) is a RecQ family helicase involved in DNA repair, cell-cycle progression, and development. Pathogenic variants in human cause the...
Bloom Syndrome helicase (Blm) is a RecQ family helicase involved in DNA repair, cell-cycle progression, and development. Pathogenic variants in human cause the autosomal recessive disorder Bloom Syndrome, characterized by predisposition to numerous types of cancer. Prior studies of mutants lacking helicase activity or protein have shown sensitivity to DNA damaging agents, defects in repairing DNA double-strand breaks (DSBs), female sterility, and improper segregation of chromosomes in meiosis. Blm orthologs have a well conserved and highly structured RecQ helicase domain, but more than half of the protein, particularly in the N-terminus, is predicted to be unstructured. Because this region is poorly conserved across multicellular organisms, we compared closely related species to identify regions of conservation, potentially indicating important functions. We deleted two of these -conserved regions in using CRISPR/Cas9 gene editing and assessed the effects on different Blm functions. Each deletion had distinct effects on different Blm activities. Deletion of either conserved region 1 (CR1) or conserved region 2 (CR2) compromised DSB repair through synthesis-dependent strand annealing and resulted in increased mitotic crossovers. In contrast, CR2 is critical for embryonic development but CR1 is not as important. CR1 deletion allows for proficient meiotic chromosome segregation but does lead to defects in meiotic crossover designation and patterning. Finally, deletion of CR2 does not lead to significant meiotic defects, indicating that while each region has overlapping functions, there are discreet roles facilitated by each. These results provide novel insights into functions of the N-terminal disordered region of Blm.
PubMed: 38659896
DOI: 10.1101/2024.04.12.589165 -
Cureus May 2024Bloom syndrome (BS) is a rare autosomal recessive genetic disorder characterized by photosensitivity, rashes on the nose and cheeks, short stature, and a predisposition...
Bloom syndrome (BS) is a rare autosomal recessive genetic disorder characterized by photosensitivity, rashes on the nose and cheeks, short stature, and a predisposition to develop cancers. In this report, we discuss the diagnosis and management of a 34-year-old Canadian male BS patient, originally from Honduras, who developed B-cell lymphoma and a subsequent non-small cell lung carcinoma (NSCLC). Given the radiosensitivity of the patient due to his BS diagnosis and the early stage of the low-grade B-cell lymphoma, we relied on surveillance as the clinical approach to his management. The treatment for NSCLC was initiated in stage III of the disease and was palliative in intent. Chemotherapy (12 rounds of paclitaxel, with the dosage gradually increasing from 48 mg to 58 mg and finally to 72 mg) was employed to shrink the left upper lobe (LUL) lung mass. Subsequently, radiotherapy (3000 cGY in 20 fractions) was administered to improve symptoms further. The radiotherapy dose schedule was modified given the patient's BS diagnosis to avoid excessive toxicity. The palliative treatment course was well tolerated by the patient and resulted in symptom relief. However, his cancer progressed over the course of the treatment, ultimately resulting in his death 18 months after the initial diagnosis of NSCLC; no autopsy was performed. We believe this report will spur clinicians to engage in fruitful discussions about tailoring chemotherapy and radiation therapy regimens for treating cancer in BS patients.
PubMed: 38860091
DOI: 10.7759/cureus.60107 -
Translational Oncology May 2024Cancer management in Africa faces diverse challenges due to limited resources, health system challenges, and other matters. Identifying hereditary cancer syndromic cases...
Cancer management in Africa faces diverse challenges due to limited resources, health system challenges, and other matters. Identifying hereditary cancer syndromic cases is crucial to improve clinical management and preventive care in these settings. This study aims to explore the clinicopathological features and genetic factors associated with hereditary cancer in Tunisia, a North African country with a rising cancer burden MATERIALS AND METHODS: Clinicopathological features and personal/family history of cancer were explored in 521 patients. Genetic analysis using Sanger and next-generation sequencing was performed for a set of patients RESULTS: Hereditary breast and ovarian cancer syndrome was the most frequent cluster in which 36 BRCA mutations were identified. We described a subgroup of patients with likely ''breast cancer-only syndrome'' among this cluster. Two cases of Li-Fraumeni syndrome with distinct TP53 mutations namely c.638G>A and c.733G>A have been identified. Genetic investigation also allowed the identification of a new BLM homozygous mutation (c.3254dupT) in one patient with multiple primary cancers. Phenotype-genotype correlation suggests the diagnosis of Bloom syndrome. A recurrent MUTYH mutation (c.1143_1144dup) was identified in three patients with different phenotypes CONCLUSION: Our study calls for comprehensive genetic education and the implementation of genetic screening in Tunisia and other African countries health systems, to reduce the burden of hereditary diseases and improve cancer outcomes in resource-stratified settings.
PubMed: 38387387
DOI: 10.1016/j.tranon.2024.101912 -
American Journal of Human Genetics May 2024
PubMed: 38701747
DOI: 10.1016/j.ajhg.2024.04.008 -
Scientific Reports May 2024Prostate cancer (PCa) ranks as the second most prevalent cancer among males globally. However, the exact mechanisms underlying its progression remain inadequately...
Prostate cancer (PCa) ranks as the second most prevalent cancer among males globally. However, the exact mechanisms underlying its progression remain inadequately elucidated. The present study sought to investigate the role and underlying molecular mechanism of hsa_circ_0001671 (circ_0001671) in the pathogenic behavior of PCa cells. Guided by the ceRNA theory, miR-27b-3p was employed to identify circRNAs that could potentially regulate Bloom Syndrome Protein (BLM). A series of experimental approaches including bioinformatics, luciferase assays, Fluorescent In Situ Hybridization (FISH), RNA-pulldown, and RNA Immunoprecipitation (RIP) were utilized to validate the miRNA sponge function of circ_0001671. Divergent primer PCR, RNase R treatments, and Sanger sequencing were conducted for the identification of circ_0001671. Quantitative RT-PCR and Western blot analyses were performed to validate gene expression levels. Both in vitro and in vivo experiments were conducted to assess the functional role of circ_0001671 in PCa cells.It was observed that the expression levels of circ_0001671 and BLM were significantly elevated in PCa tissues and cell lines, whereas miR-27b-3p showed decreased expression. Circ_0001671 was found to promote cellular proliferation, migration, and invasion, while inhibiting apoptosis. In vivo assays confirmed that circ_0001671 facilitated tumor growth. Further mechanistic studies revealed that circ_0001671 acted as a competing endogenous RNA (ceRNA) for BLM by sponging miR-27b-3p. The oncogenic role of circ_0001671 in PCa was shown to be modulated through the miR-27b-3p/BLM axis. In conclusion, circ_0001671 exerts an oncogenic effect in prostate cancer through the regulation of BLM by sponging miR-27b-3p, thus suggesting a novel molecular target for the treatment of PCa.
Topics: Humans; MicroRNAs; Prostatic Neoplasms; Male; RNA, Circular; Gene Expression Regulation, Neoplastic; Cell Proliferation; Cell Line, Tumor; Disease Progression; Animals; Mice; Cell Movement; Mice, Nude; Apoptosis
PubMed: 38806577
DOI: 10.1038/s41598-024-63068-x