Asymptomatic Bloom syndrome diagnosed by chance in a patient with breast cancer.

Bloom syndrome (BS) is a rare genetic disorder caused by biallelic inactivation of the BLM gene, which usually manifests in childhood by significant growth retardation, immune deficiency, characteristic skin lesions, cancer predisposition and other distinguishable disease features. To our knowledge, all prior instances of BS have been identified via intentional analysis of patients with clinical suspicion for this disease or DNA testing of members of affected pedigrees. We describe an incidental finding of BS, which occurred upon routine germline DNA analysis of consecutive breast cancer patients. The person with the biallelic pathogenic BLM c.1642C>T (p.Gln548Ter) variant remained clinically healthy for 38 years until she developed breast cancer. Detailed examination of this woman, which was carried out after the genetic diagnosis, revealed mild features of BS. A sister chromatid exchange (SCE) test confirmed the presence of this syndrome. The tumor exhibited triple-negative receptor status, a high proliferation rate, a low tumor mutation burden (TMB), and a moderate level of chromosomal instability (homologous recombination deficiency (HRD) score = 29). The patient showed normal tolerability to radiotherapy and several regimens of cytotoxic therapy. Thus, some BS patients may remain undiagnosed due to the mild phenotype of their disease. BLM should be incorporated in gene panels utilized for germline DNA testing of cancer patients.

One-pot synthesis and pharmacological evaluation of new quinoline/pyrimido-diazepines as pulmonary antifibrotic agents.

Aim: Pulmonary fibrosis is a life threating disease which requires an immediate treatment and due to the limited medications, this study focused on synthesizing a series of quinoline-based pyrimidodiazepines 4a-f as a novel antifibrotic hit.Materials & methods: The target compounds were synthesized via a one-pot reaction then investigated in a rat model of lung fibrosis induced by bleomycin (BLM).Results: Results revealed significant attenuation of the tested pro-inflammatory cytokines, fibrotic genes and apoptotic markers; however, Bcl-2 was upregulated, indicating a protective effect against fibrosis. Moreover, the molecular docking studies highlighted promising interactions between compounds 4b and 4c and specific amino acids within the protein pockets of caspase-3 (ARG341 and THR177), malondialdehyde (LYS195, LYS118 and ARG188) and TNF-α (SER99 and NME102).Conclusion: Compounds 4b and 4c emerge as promising candidates for further preclinical investigation as pulmonary antifibrotic agents.

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Bone morphogenetic protein 4 ameliorates bleomycin-induced pulmonary fibrosis in mice by repressing NLRP3 inflammasome activation and epithelial-mesenchymal transition.

Background: Idiopathic pulmonary fibrosis (IPF) is a progressive and deadly lung disease with limited therapeutic options. Bone morphogenetic protein 4 (BMP4), a multifunctional growth factor that belongs to the transforming growth factor-ß superfamily, is able to relieve pulmonary fibrosis in mice; nevertheless, the potential mechanism of action remains largely unknown. Growing evidence supports the notion that reiterant damage to the alveolar epithelial cells (AECs) is usually the "prime mover" for pulmonary fibrosis. Here, we examined the effect and mechanisms of BMP4 on bleomycin (BLM)-induced activation of NLR family pyrin domain containing 3 (NLRP3) inflammasome and epithelial-mesenchymal transition (EMT) in vivo and in vitro. Methods: The in vivo impact of BMP4 was investigated in a BLM mouse model. Histopathologic changes were analyzed by hematoxylin-eosin (H&E) and Masson's trichrome staining. The NLRP3 inflammasome activation was determined by quantitative real time polymerase chain reaction (qRT-PCR) and immunofluorescence staining. Biomarkers of EMT were measured by qRT-PCR, Western blot and immunofluorescence staining. The in vitro impact of BMP4 on BLM-induced NLRP3 inflammasome activation and EMT was explored in A549 AECs. We also evaluated whether BMP4 inhibited BLM-activated ERK1/2 signaling to address the possible molecular mechanisms. Results: BMP4 was significantly downregulated in the mouse lungs from BLM-induced pulmonary fibrosis. BMP4+/- mice presented with more severe lung fibrosis in response to BLM, and accelerated NLRP3 inflammasome activation and EMT process compared with that in BMP4+/+ mice. Whereas overexpression of BMP4 by injecting adeno-associated virus (AAV) 9 into mice attenuated BLM-induced fibrotic changes, NLRP3 inflammasome activation, and EMT in the mouse lungs, thus exerting protective efficacy against lung fibrosis. In vitro, BMP4 significantly reduced BLM-induced activation of NLRP3 inflammasome and EMT in human alveolar epithelial A549 cells. Mechanically, BMP4 repressed BLM-induced activation of ERK1/2 signaling in vivo and in vitro, suggesting that ERK1/2 inactivation contributes to BMP4-induced effects on BLM-induced activation of NLRP3 inflammasome and EMT. Conclusions: Our findings suggest that BMP4 can suppress NLRP3 inflammasome activation and EMT in AECs via inhibition of ERK1/2 signaling pathway, thus has a potential for the treatment of pulmonary fibrosis.

Assessing the impact of triiodothyronine treatment on the lung microbiome of mice with pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF), an interstitial lung disease, is characterized by the exacerbation of progressive pulmonary fibrosis (PF). IPF primarily affects older individuals and can lead to respiratory failure. This study aimed to assess the effects of triiodothyronine (T3) treatment on the lung microbiome of mice with PF. METHODS: Mice were perfused with bleomycin (BLM) to establish a PF model. Using a randomized design, 40 female specific pathogen-free (SPF) C57BL6/N mice were divided into four groups: saline, saline + T3, BLM, and BLM + T3. Histological morphology was assessed through Hematoxylin and Eosin staining as well as Masson's Trichrome staining. For the identification of lung bacteria, 16S rRNA gene sequencing was employed. An Enzyme-Linked Immunosorbent Assay was used to measure total T3 (TT3), free T3 (FT3, and reverse T3 (rT3) levels in the peripheral serum. RESULTS: T3 treatment ameliorated BLM-induced lung fibrosis and structural damage. The microbiome experienced a decrease in the abundance of Proteobacteria, Bacteroides, and Actinomycetes and an increase in the abundance of Firmicutes when exposed to BLM; however, T3 treatment reversed this effect. The four groups showed no significant difference in alpha microbiome diversity (P > 0.05). Serum concentrations of TT3 and FT3 were positively correlated with microbiome abundance (P < 0.05). Administration of T3 enhanced the microbiota in PF without affecting the diversity and biological functions of the microbiome (P > 0.05). CONCLUSION: The administration of T3 demonstrated a favorable impact on the lung microbiota of mice afflicted with PF, thereby partially substantiating the potential role of T3 as a therapeutic agent in the management of PF.

Whole-Exome Sequencing Identifies Germline BLM Mutation in Ovarian Hepatoid Adenocarcinoma with Favorable Response to Niraparib and Anlotinib Combination Therapy-A Case Report and Literature Review.

Hepatoid adenocarcinoma of the ovary represents a rare and malignant extrahepatic tumor that shares morphological and immunophenotypic similarities with hepatocellular carcinoma. Due to the ambiguous histomorphology and aggressive behavior, the diagnosis and management of hepatoid adenocarcinoma of the ovary present unique challenges. Here, we present a 67-year-old woman with massive ascites and disseminated peritoneal implants at initial diagnosis. She was treated with six cycles of neoadjuvant therapy (albumin-bound paclitaxel + nedaplatin + bevacizumab) and a debulking surgery, followed by eight cycles of postoperative adjuvant therapy (albumin-bound paclitaxel + carboplatin + bevacizumab). Elaborate pathology workup found significant involvement of angiogenesis in the tumor and confirmed the diagnosis via immunohistochemistry. Further molecular characterization of the tumor by whole-exome sequencing (WES) revealed a novel heterozygous germline mutation (NM_000057.2, c.1290_1291delinsATCAGGCCTCCATAG, p.Y430fs1) in gene BLM, likely pathogenic, suggesting a potential candidate for Poly (ADP-ribose) polymerase (PARP) inhibitors. For the maintenance therapy, she received a combination of the PARP inhibitor niraparib and the antiangiogenic anlotinib. As of now, the patient has achieved a partial response, with no apparent evidence of disease progression observed nearly 30 months. Our study sheds light on the WES-based profiling in rare cancers to screen for any treatable targets with otherwise no standard therapeutic options. The promising results with the niraparib-anlotinib combination suggest its potential as a maintenance therapy option for hepatoid adenocarcinoma of the ovary, which warrants validation in future larger cohort.

Exploring the preventive effects of Jie Geng Tang on pulmonary fibrosis induced in vitro and in vivo: a network pharmacology approach.

Pulmonary fibrosis is a debilitating lung disease marked by excessive fibrotic tissue accumulation, which significantly impairs respiratory function. Given the limitations of current therapies, there is an increasing interest in exploring traditional herbal formulations like Jie Geng Tang (JGT) for treatment. This study examines the potential of JGT and its bioactive component, quercetin, in reversing bleomycin (BLM)-induced pulmonary fibrosis in mice. We employed a BLM-induced MLE-12 cell damage model for in vitro studies and a bleomycin-induced fibrosis model in C57BL/6 mice for in vivo experiments. In vitro assessments showed that JGT significantly enhanced cell viability and reduced apoptosis in MLE-12 cells treated with BLM. These findings underscore JGT's potential for cytoprotection against fibrotic agents. In vivo, JGT was effective in modulating the expression of E-cadherin and vimentin, key markers of the epithelial-mesenchymal transition (EMT) pathway, indicating its role in mitigating EMT-associated fibrotic changes in lung tissue. Quercetin, identified through network pharmacology analysis as a potential key bioactive component of JGT, was highlighted for its role in the regulatory mechanisms underlying fibrosis progression, particularly through the modulation of the IL-17 pathway and Il6 expression. By targeting inflammatory pathways and key processes like EMT, JGT and quercetin offer a potent alternative to conventional therapies, meriting further clinical exploration to harness their full therapeutic potential in fibrotic diseases.

ATM, BLM, and CDH1 gene co-mutations in a high-grade endometrial stromal sarcoma patient with multiple abdominal cavity metastases: a case report and literature review.

BACKGROUND: High-grade endometrial stromal sarcoma (HG-ESS) is a rare malignant tumor with poor prognosis. To overcome the limitations of current treatment for advanced patients, the intervention of targeted drug therapy is urgently needed. CASE PRESENTATION: A 74-year-old married woman who presented with abdominal distension and lower abdominal pain was admitted to Hebei General Hospital. After surgery, immunohistochemical staining revealed a malignant tumor which was consistent with HG-ESS. Tumor recurrence occurred 2 months after surgery. Then the patient underwent chemotherapy with two courses but responded poorly. Subsequently we observed ATM, BLM, and CDH1 co-mutations by Next Generation Sequencing (NGS). Then the patient received pamiparib, which resulted in a 10-month progression-free survival (PFS) and is now stable with the administration of sintilimab in combination with pamiparib and anlotinib. CONCLUSIONS: Due to the successful use of poly ADP-ribose polymerase inhibitor (PARPi) on HG-ESS, we suggest that the selection of effective targeted drugs combined with anti- programmed death-1 (PD-1) drug therapy based on genetic testing may become a new option for the treatment of homologous repair deficient (HR-deficient) HG-ESS.

PA200-Mediated Proteasomal Protein Degradation and Regulation of Cellular Senescence.

Cellular senescence is closely related to DNA damage, proteasome inactivity, histone loss, epigenetic alterations, and tumorigenesis. The mammalian proteasome activator PA200 (also referred to as PSME4) or its yeast ortholog Blm10 promotes the acetylation-dependent degradation of the core histones during transcription, DNA repair, and spermatogenesis. According to recent studies, PA200 plays an important role in senescence, probably because of its role in promoting the degradation of the core histones. Loss of PA200 or Blm10 is a major cause of the decrease in proteasome activity during senescence. In this paper, recent research progress on the association of PA200 with cellular senescence is summarized, and the potential of PA200 to serve as a therapeutic target in age-related diseases is discussed.

The potential ameliorating effect of vitamin E on bleomycin - induced lung fibrosis in adult albino rats.

Lung fibrosis is a critical interstitial lung disease with poor prognosis. There is an urgent need to develop a proper and cost-effective therapeutic modality that can reverse and/or ameliorate lung fibrosis. Vitamin E is one of the widely investigated dietary antioxidants which has been linked to improvement of many health problems. The current study was conducted to evaluate the possible roles of vitamin E in prevention and treatment of bleomycin (BLM) induced lung fibrosis. Physiological, anatomical, histopathological and immunohistochemical studies were done to assess and compare between the structure and function of the lung tissue in lung fibrosis model, early and late treated groups with vitamin E. Furthermore, measurement of transforming growth factor-ß(TGF-ß), E-cadherin, Smad-3, BAX, BCL2, malondialdehyde (MDA), and superoxide dismutase (SOD) were done. The study revealed that administration of vitamin E helped to improve signs of lung fibrosis, as reflected by amelioration of structure and functions of lungs as well as the decrease in TGF-ß levels and inhibition of α-SMA/collagen I profibrotic pathway. These findings highlight the importance of administration of vitamin E as a prophylactic agent prior to BLM therapy and as an adjuvant treatment in cases of lung fibrosis.

An Assessment of Administration Route on MSC-sEV Therapeutic Efficacy.

Mesenchymal stem/stromal cell-derived small extracellular vesicles (MSC-sEVs) are promising therapeutic agents. In this study, we investigated how the administration route of MSC-sEVs affects their therapeutic efficacy in a mouse model of bleomycin (BLM)-induced skin scleroderma (SSc). We evaluated the impact of topical (TOP), subcutaneous (SC), and intraperitoneal (IP) administration of MSC-sEVs on dermal fibrosis, collagen density, and thickness. All three routes of administration significantly reduced BLM-induced fibrosis in the skin, as determined by Masson's Trichrome staining. However, only TOP administration reduced BLM-induced dermal collagen density, with no effect on dermal thickness observed for all administration routes. Moreover, SC, but not TOP or IP administration, increased anti-inflammatory profibrotic CD163+ M2 macrophages. These findings indicate that the administration route influences the therapeutic efficacy of MSC-sEVs in alleviating dermal fibrosis, with TOP administration being the most effective, and this efficacy is not mediated by M2 macrophages. Since both TOP and SC administration target the skin, the difference in their efficacy likely stems from variations in MSC-sEV delivery in the skin. Fluorescence-labelled TOP, but not SC MSC-sEVs when applied to skin explant cultures, localized in the stratum corneum. Hence, the superior efficacy of TOP over SC MSC-sEVs could be attributed to this localization. A comparison of the proteomes of stratum corneum and MSC-sEVs revealed the presence of >100 common proteins. Most of these proteins, such as filaggrin, were known to be crucial for maintaining skin barrier function against irritants and toxins, thereby mitigating inflammation-induced fibrosis. Therefore, the superior efficacy of TOP MSC-sEVs over SC and IP MSC-sEVs against SSc is mediated by the delivery of proteins to the stratum corneum to reinforce the skin barrier.

Suppressors of Blm-deficiency identify three novel proteins that facilitate DNA repair in Ustilago maydis.

To identify new molecular components of the Brh2-governed homologous recombination (HR)-network in the highly radiation-resistant fungus Ustilago maydis, we undertook a genetic screen for suppressors of blm-KR hydroxyurea (HU)-sensitivity. Twenty DNA-damage sensitive mutants were obtained, three of which showing slow-growth phenotypes. Focusing on the "normally" growing candidates we identified five mutations, two in previously well-defined genes (Rec2 and Rad51) and the remaining three in completely uncharacterized genes (named Rec3, Bls9 and Zdr1). A common feature among these novel factors is their prominent role in DNA repair. Rec3 contains the P-loop NTPase domain which is most similar to that found in U. maydis Rec2 protein, and like Rec2, Rec3 plays critical roles in induced allelic recombination, is crucial for completion of meiosis, and with regard to DNA repair Δrec3 and Δrec2 are epistatic to one another. Importantly, overexpression of Brh2 in Δrec3 can effectively restore DNA-damage resistance, indicating a close functional connection between Brh2 and Rec3. The Bls9 does not seem to have any convincing domains that would give a clue as to its function. Nevertheless, we present evidence that, besides being involved in DNA-repair, Bls9 is also necessary for HR between chromosome homologs. Moreover, Δbls9 showed epistasis with Δbrh2 with respect to killing by DNA-damaging agents. Both, Rec3 and Bls9, play an important role in protecting the genome from mutations. Zdr1 is Cys2-His2 zinc finger (C2H2-ZF) protein, whose loss does not cause a detectable change in HR. Also, the functions of both Bls9 and Zdr1 genes are dispensable in meiosis and sporulation. However, Zdr1 appears to have overlapping activities with Blm and Mus81 in protecting the organism from methyl methanesulfonate- and diepoxybutane-induced DNA-damage. Finally, while deletion of Rec3 and Zdr1 can suppress HU-sensitivity of blm-KR, Δgen1, and Δmus81 mutants, interestingly loss of Bls9 does not rescue HU-sensitivity of Δgen1.

Human Muse cells isolated from preterm- and term-umbilical cord delivered therapeutic effects in rat bleomycin-induced lung injury model without immunosuppressant.

BACKGROUND: Bleomycin (BLM)-induced lung injury is characterized by mixed histopathologic changes with inflammation and fibrosis, such as observed in human patients with bronchopulmonary dysplasia, idiopathic pulmonary fibrosis, and chronic obstructive pulmonary disease. Although no curative therapies for these lung diseases exist, stem cell therapy has emerged as a potential therapeutic option. Multilineage-differentiating stress-enduring (Muse) cells are endogenous pluripotent- and macrophage-like stem cells distributed in various adult and fetal tissues as stage-specific embryonic antigen-3-positive cells. They selectively home to damaged tissue by sensing sphingosine-1-phosphate and replace the damaged/apoptotic cells by in vivo differentiation. Clinical trials for some human diseases suggest the safety and therapeutic efficacy of intravenously injected human leukocyte antigen-mismatched allogenic Muse cells from adult bone marrow (BM) without immunosuppressant. Here, we evaluated the therapeutic effects of human Muse cells from preterm and term umbilical cord (UC), and adult BM in a rat BLM-induced lung injury model. METHODS: Rats were endotracheally administered BLM to induce lung injury on day 0. On day 3, human preterm UC-Muse, term UC-Muse, or adult BM-Muse cells were administered intravenously without immunosuppressants, and rats were subjected to histopathologic analysis on day 21. Body weight, serum surfactant protein D (SP-D) levels, and oxygen saturation (SpO2) were monitored. Histopathologic lung injury scoring by the Ashcroft and modified American Thoracic Society document scales, quantitative characterization of engrafted Muse cells, RNA sequencing analysis, and in vitro migration assay of infused Muse cells were performed. RESULTS: Rats administered preterm- and term-UC-Muse cells exhibited a significantly better recovery based on weight loss, serum SP-D levels, SpO2, and histopathologic lung injury scores, and a significantly higher rate of both Muse cell homing to the lung and alveolar marker expression (podoplanin and prosurfactant protein-C) than rats administered BM-Muse cells. Rats receiving preterm-UC-Muse cells showed statistically superior results to those receiving term-UC-Muse cells in many of the measures. These findings are thought to be due to higher expression of genes related to cell migration, lung differentiation, and cell adhesion. CONCLUSION: Preterm UC-Muse cells deliver more efficient therapeutic effects than term UC- and BM-Muse cells for treating BLM-induced lung injury in a rat model.

Circ_0001671 regulates prostate cancer progression through miR-27b-3p/BLM axis.

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.

Extrachromosomal telomere DNA derived from excessive strand displacements.

Alternative lengthening of telomeres (ALT) is a telomere maintenance mechanism mediated by break-induced replication, evident in approximately 15% of human cancers. A characteristic feature of ALT cancers is the presence of C-circles, circular single-stranded telomeric DNAs composed of C-rich sequences. Despite the fact that extrachromosomal C-rich single-stranded DNAs (ssDNAs), including C-circles, are unique to ALT cells, their generation process remains undefined. Here, we introduce a method to detect single-stranded telomeric DNA, called 4SET (Strand-Specific Southern-blot for Single-stranded Extrachromosomal Telomeres) assay. Utilizing 4SET, we are able to capture C-rich single-stranded DNAs that are near 200 to 1500 nucleotides in size. Both linear C-rich ssDNAs and C-circles are abundant in the fractions of cytoplasm and nucleoplasm, which supports the idea that linear and circular C-rich ssDNAs are generated concurrently. We also found that C-rich ssDNAs originate during Okazaki fragment processing during lagging strand DNA synthesis. The generation of C-rich ssDNA requires CST-PP (CTC1/STN1/TEN1-PRIMASE-Polymerase alpha) complex-mediated priming of the C-strand DNA synthesis and subsequent excessive strand displacement of the C-rich strand mediated by the DNA Polymerase delta and the BLM helicase. Our work proposes a model for the generation of C-rich ssDNAs and C-circles during ALT-mediated telomere elongation.

BLM helicase unwinds lagging strand substrates to assemble the ALT telomere damage response.

The Bloom syndrome (BLM) helicase is critical for alternative lengthening of telomeres (ALT), a homology-directed repair (HDR)-mediated telomere maintenance mechanism that is prevalent in cancers of mesenchymal origin. The DNA substrates that BLM engages to direct telomere recombination during ALT remain unknown. Here, we determine that BLM helicase acts on lagging strand telomere intermediates that occur specifically in ALT-positive cells to assemble a replication-associated DNA damage response. Loss of ATRX was permissive for BLM localization to ALT telomeres in S and G2, commensurate with the appearance of telomere C-strand-specific single-stranded DNA (ssDNA). DNA2 nuclease deficiency increased 5'-flap formation in a BLM-dependent manner, while telomere C-strand, but not G-strand, nicks promoted ALT. These findings define the seminal events in the ALT DNA damage response, linking aberrant telomeric lagging strand DNA replication with a BLM-directed HDR mechanism that sustains telomere length in a subset of human cancers.

A case of Bloom syndrome manifesting with therapy-related myelodysplastic syndromes harboring a novel BLM gene variant.

Bloom syndrome (BS) is an autosomal recessive genetic disorder caused by variants in the BLM gene. BS is characterized by distinct facial features, elongated limbs, and various dermatological complications including photosensitivity, poikiloderma, and telangiectatic erythema. The BLM gene encodes a RecQ helicase critical for genome maintenance, stability, and repair, and a deficiency in functional BLM protein leads to genomic instability and high predisposition to various types of cancers, particularly hematological and gastrointestinal malignancies. Here, we report a case of BS with a previously unreported variant in the BLM gene. The patient was a 34-year-old woman who presented with short stature, prominent facial features, and a history of malignancies, including lymphoma, breast cancer, and myelodysplastic syndromes (MDS). She was initially treated with azacitidine for MDS and showed transient improvement, but eventually died at age of 35 due to progression of MDS. Genetic screening revealed compound heterozygous variants in the BLM gene, with a recurrent variant previously reported in BS in one allele and a previously unreported variant in the other allele. Based on her characteristic clinical features and the presence of heterozygous variants in the BLM gene, she was diagnosed with BS harboring compound heterozygous BLM variants.

Characteristics of potential adopters of wild horses and their willingness-to-pay for wild horses.

An overabundance of wild horses and burros on federal lands can lead to suboptimal welfare when there are insufficient forage and water resources. Placing some of these animals in private homes has been identified as a key part of the solution. A nationwide online survey completed by 2,247 current and former horse owners is used to assess the feasibility of accommodating this strategy. The survey tool addressed basic horse ownership and demographic information, previous experience with wild horses, and hypothetical wild horse adoption scenarios. Results suggest that most respondents are receptive to the idea of adopting a wild horse, with previous adopters and younger potential adopters showing greater willingness-to-pay. By reducing existing barriers to adoption, which includes educating the horse-owning public on adoption requirements, expanding the training of wild horses, and targeting certain age groups of potential adopters, our study suggests that it may be possible to increase the annual number of adoptions over current levels. With appropriate and informed strategies, enhanced welfare of privately adopted and on-range animals can be achieved.

Genetic variation in the BLM gene and its expression in the ovaries is closely related to kidding number in goats.

Bloom (BLM) helicase plays an important role in DNA replication and the maintenance of genome integrity. BLM protein deficiency, which plays a vital role in the sperm-egg union and germ-cell development during reproduction, can lead to severe DNA damage in goats. However, the effect of BLM protein deficiency on goat litter size has not been reported. Herein, we studied the association between the genetic variation in the BLM gene and the number of kids per litter in Guizhou white goats. We explored differences in the expression of the BLM protein in the follicles of single and multi-kid nanny goats. We also analyzed the effects of dysregulated BLM gene expression on the proliferation and apoptosis of ovarian granulosa cells and the expression of genes related to follicle development in goats. Five single nucleotide polymorphism (SNP) loci, including the non-synonymous mutations g.38179 A > G, g.40626 G > C and g.89621 T > G; the intron synonymous mutation g.56961 G > A and the exon synonymous mutation g.65796 C > T were found in the BLM gene. All SNPs loci were in Hardy-Weinberg equilibrium, and correlation analysis showed that the g.65796 C > T and g.89621 T > G loci polymorphism was strongly associated with litter size in the first three litters (P < 0.05). The diplogenotype Hap 2/2 (AAGGAACCTT) showed no significant difference in litter size between different births, indicating that the diploid genotype is stable in different litter sizes. Bioinformatics analysis showed that three non-synonymous mutation loci (p.T488A, p.A662S, and p.S1373A) could affect BLM protein stability, and mutations in p.T488A and p.S1373A led to changes in amino acid polarity and associated interactions. qPCR results showed that the expression level of the BLM gene in the uterus and ovaries of TT genotype nanny goats was significantly higher than that of GG genotype nanny goats. Indirect immunofluorescence assay (IF) showed that the BLM protein was significantly overexpressed in both the primordial and growing follicles of nanny goats with multiple kids (P < 0.01). Disrupting BLM gene expression in the ovarian granulosa cells down-regulated the expression of the Cyp19A1 gene. It also significantly inhibited the proliferation of follicles and induces early apoptosis of the granulosa cells. These findings confirm that polymorphism in the BLM gene is closely related to the littering traits of Guizhou white goats, and it affects the reproductive performance of nanny goats by regulating the development of the oocytes and granulosa cells. This work provides new evidence on the regulatory effect of the BLM gene on the litter size of nanny goats.

BLM and BRCA1-BARD1 coordinate complementary mechanisms of joint DNA molecule resolution.

The Bloom syndrome helicase BLM interacts with topoisomerase IIIα (TOP3A), RMI1, and RMI2 to form the BTR complex, which dissolves double Holliday junctions and DNA replication intermediates to promote sister chromatid disjunction before cell division. In its absence, structure-specific nucleases like the SMX complex (comprising SLX1-SLX4, MUS81-EME1, and XPF-ERCC1) can cleave joint DNA molecules instead, but cells deficient in both BTR and SMX are not viable. Here, we identify a negative genetic interaction between BLM loss and deficiency in the BRCA1-BARD1 tumor suppressor complex. We show that this is due to a previously overlooked role for BARD1 in recruiting SLX4 to resolve DNA intermediates left unprocessed by BLM in the preceding interphase. Consequently, cells with defective BLM and BRCA1-BARD1 accumulate catastrophic levels of chromosome breakage and micronucleation, leading to cell death. Thus, we reveal mechanistic insights into SLX4 recruitment to DNA lesions, with potential clinical implications for treating BRCA1-deficient tumors.