Loss of TDP-43 in male germ cells causes meiotic failure and impairs fertility in mice.

Meiotic arrest is a common cause of human male infertility, but the causes of this arrest are poorly understood. Transactive response DNA-binding protein of 43 kDa (TDP-43) is highly expressed in spermatocytes in the preleptotene and pachytene stages of meiosis. TDP-43 is linked to several human neurodegenerative disorders wherein its nuclear clearance accompanied by cytoplasmic aggregates underlies neurodegeneration. Exploring the functional requirement for TDP-43 for spermatogenesis for the first time, we show here that conditional KO (cKO) of the Tardbp gene (encoding TDP-43) in male germ cells of mice leads to reduced testis size, depletion of germ cells, vacuole formation within the seminiferous epithelium, and reduced sperm production. Fertility trials also indicated severe subfertility. Spermatocytes of cKO mice showed failure to complete prophase I of meiosis with arrest at the midpachytene stage. Staining of synaptonemal complex protein 3 and γH2AX, markers of the meiotic synaptonemal complex and DNA damage, respectively, and super illumination microscopy revealed nonhomologous pairing and synapsis defects. Quantitative RT-PCR showed reduction in the expression of genes critical for prophase I of meiosis, including Spo11 (initiator of meiotic double-stranded breaks), Rec8 (meiotic recombination protein), and Rad21L (RAD21-like, cohesin complex component), as well as those involved in the retinoic acid pathway critical for entry into meiosis. RNA-Seq showed 1036 upregulated and 1638 downregulated genes (false discovery rate <0.05) in the Tardbp cKO testis, impacting meiosis pathways. Our work reveals a crucial role for TDP-43 in male meiosis and suggests that some forms of meiotic arrest seen in infertile men may result from the loss of function of TDP-43.

Results of Testing Children for Severe Acute Respiratory Syndrome Coronavirus-2 Through a Community-based Testing Site.

OBJECTIVE: To describe the demographics, clinical features, and test results of children referred from their primary provider for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in the community setting. STUDY DESIGN: Retrospective cross-sectional study of children ≤22 years of age who were tested for SARS-CoV-2 at a community-based specimen collection site in Washington, DC, affiliated with a large children's hospital between March 21 and May 16, 2020. RESULTS: Of the 1445 patients tested at the specimen collection site for SARS-CoV-2 virus, 408 (28.2%) had a positive polymerase chain reaction test. The daily positivity rate increased over the study period, from 5.4% during the first week to a peak of 47.4% (Ptrend < .001). Patients with fever (aOR, 1.7; 95% CI, 1.3-2.3) or cough (aOR, 1.4; 95% CI, 1.1-1.9) and those with known contact with someone with confirmed SARS-CoV-2 infection (aOR, 1.6; 95% CI, 1.0-2.4.) were more likely have a positive test, but these features were not highly discriminating. CONCLUSIONS: In this cohort of mildly symptomatic or well children and adolescents referred to a community drive-through/walk-up SARS-CoV-2 testing site because of risk of exposure or clinical illness, 1 in 4 patients had a positive test. Children and young adults represent a considerable burden of SARS-CoV-2 infection. Assessment of their role in transmission is essential to implementing appropriate control measures.

Intravitreal Methotrexate for Recalcitrant Epiretinal Membrane Reproliferation.

This article reports a case of a 65-year-old woman with recalcitrant recurrent epiretinal membrane (ERM) treated with revision vitrectomy and membrane peeling followed by 12 weekly intravitreal methotrexate injections. Visual acuity and central macular thickness significantly improved, and no ERM recurrence developed 7 months after surgery. This case represents the first documented use of methotrexate to treat surgically resistant ERM reproliferation and indicates a potential for its use in cases that do not respond to standard treatment. [Ophthalmic Surg Lasers Imaging Retina. 2022;53:49-51.].