Elucidation of the molecular mechanism of the breakage-fusion-bridge (BFB) cycle using a CRISPR-dCas9 cellular model.

Chromosome instability (CIN) is frequently observed in many tumors. The breakage-fusion-bridge (BFB) cycle has been proposed to be one of the main drivers of CIN during tumorigenesis and tumor evolution. However, the detailed mechanisms for the individual steps of the BFB cycle warrants further investigation. Here, we demonstrated that a nuclease-dead Cas9 (dCas9) coupled with a telomere-specific single-guide RNA (sgTelo) can be used to model the BFB cycle. First, we showed that targeting dCas9 to telomeres using sgTelo impeded DNA replication at telomeres and induced a pronounced increase of replication stress and DNA damage. Using Single-Molecule Telomere Assay via Optical Mapping (SMTA-OM), we investigated the genome-wide features of telomeres in the dCas9/sgTelo cells and observed a dramatic increase of chromosome end fusions, including fusion/ITS+ and fusion/ITS-.Consistently, we also observed an increase in the formation of dicentric chromosomes, anaphase bridges, and intercellular telomeric chromosome bridges (ITCBs). Utilizing the dCas9/sgTelo system, we uncovered many novel molecular and structural features of the ITCB and demonstrated that multiple DNA repair pathways are implicated in the formation of ITCBs. Our studies shed new light on the molecular mechanisms of the BFB cycle, which will advance our understanding of tumorigenesis, tumor evolution, and drug resistance.

Use of the Western blot technique to identify the immunogenic proteins of Borrelia burgdorferi for developing a Lyme disease vaccine.

BACKGROUND: Lyme disease is a serious infectious disease having a restricted worldwide distribution for which there is no vaccine available for human use. OBJECTIVE: This study was designed to determine common reactive antigens involved in Borrelia burgdorferi (Bb) infection that are recognized in mammalian sera that may be useful for vaccine development. METHODS: Blood samples were collected from patients with documented Lyme disease, and from rabbits and mice experimentally infected with either tick-transmitted or culture-grown Borrelia burgdorferi. All samples were then processed for sera. For performing the Western blots, sonicated Bb organisms (whole cell lysates) and protein ladders were separated by protein gel electrophoresis. Immune reactivities of the electrophoresed proteins with the serum samples were then probed with anti-HRP IgG reagent. RESULTS: Rabbit, mouse and human sera consistently reacted with the 41 kDa band of Bb which corresponded to the flagellin protein - the major protein component of this organism's periplasmic flagella, also known as axial filaments or fibrils. Various other Bb antigens of wide molecular weight ranges were also recognized by rabbit and human sera, and less frequently with mouse sera. CONCLUSION: The strong immune response to the 41 kDa flagellin protein by the different mammalian species suggests the utility of a possible vaccine targeting this protein, although other proteins may also be appropriate, for preventing Lyme disease following a bite from an infected tick.

The psychological burden associated with Ehlers-Danlos syndromes: a systematic review.

CONTEXT: Ehlers-Danlos syndromes (EDS) are disorders of connective tissue that lead to a wide range of clinical presentations. While we are beginning to understand the association between EDS and psychological manifestations, it is critical that we further elucidate the relationship between the two. Understanding the correlation between EDS and mental health will better ensure swift diagnosis and effective treatment for patients. OBJECTIVES: This study aims to systematically examine and report the prevalence of psychiatric disorders in the EDS population. METHODS: The PubMed database was searched on June 14, 2021 for articles published from January 2011 to June 2021. We included original, evidence-based, peer-reviewed journal articles in English that reported information on psychiatric disorders among EDS patients. Psychiatric disorders and psychological conditions were limited to those included in the "psychology" and "mental disorders" Medical Subject Headings (MeSH) search terms defined by the National Library of Medicine. Publications identified utilizing this search strategy by M.K. were imported into the Covidence system, where they first underwent a title and abstract screening process by three independent reviewers (M.K., K.L., H.G.). During the full-text review, two independent reviewers read the full text of the questionable articles to assess their eligibility for inclusion. Studies were excluded if they did not meet our target objective or if they were not in English or if they were opinion pieces, conference abstracts, or review articles. Data were extracted from the shortlisted studies by reviewers. During the data extraction phase, the quality and risk of publication bias were assessed by two independent reviewers utilizing the National Institutes of Health (NIH) Study Quality Assessment Tools. Any disagreements in study selection, data extraction, or quality assessment were adjudicated via discussion between the two reviewers, utilizing a third reviewer as a decider if necessary. RESULTS: Out of 73 articles identified, there were no duplicates. A total of 73 records were screened, but only 40 articles were assessed in full text for eligibility. A total of 23 articles were ultimately included, which collectively discussed 12,298 participants. Ten (43.5%) of the included studies were cross-sectional in design, three (13.0%) were case reports, and three (13.0%) were retrospective chart reviews. The remaining seven (30.4%) articles were either case-control, cohort, qualitative, controlled observational, or validation studies. Twelve (52.2%) of the studies reported data on depression disorders, six of which reported prevalence data. Nine (39.1%) of the studies reported data on anxiety disorders, five of which reported prevalence data. Studies that reported nonprevalence data presented odds-ratio, mean scores on psychiatric evaluations, and other correlation statistics. Psychiatric disorders that were most reported in these articles were mood disorders (n=11), anxiety disorders (n=9), and neurodevelopmental disorders (n=7). Although the reports varied, the highest psychiatric prevalence reports in EDS patients involved language disorders (63.2%), attention-deficit/hyperactivity disorder (ADHD) (52.4%), anxiety (51.2%), learning disabilities (42.4%), and depression (30.2%). CONCLUSIONS: Although mood disorders were cited in more articles, the highest reported prevalence was for language disorders and ADHD. This discrepancy highlights the importance of performing more research to better understand the relationship between EDS and psychiatric disorders.