Pou3f1 orchestrates a gene regulatory network controlling contralateral retinogeniculate projections.

The balance of contralateral and ipsilateral retinogeniculate projections is critical for binocular vision, but the transcriptional programs regulating this process remain ill defined. Here we show that the Pou class homeobox protein POU3F1 is expressed in nascent mouse contralateral retinal ganglion cells (cRGCs) but not ipsilateral RGCs (iRGCs). Upon Pou3f1 inactivation, the proportion of cRGCs is reduced in favor of iRGCs, leading to abnormal projection ratios at the optic chiasm. Conversely, misexpression of Pou3f1 in progenitors increases the production of cRGCs. Using CUT&RUN and RNA sequencing in gain- and loss-of-function assays, we demonstrate that POU3F1 regulates expression of several key members of the cRGC gene regulatory network. Finally, we report that POU3F1 is sufficient to induce RGC-like cell production, even in late-stage retinal progenitors of Atoh7 knockout mice. This work uncovers POU3F1 as a regulator of the cRGC transcriptional program, opening possibilities for optic nerve regenerative therapies.

Selection into youth cricket academies: The influence of relative age and maturity status.

The aim of the study was to examine the birth quartile and maturity status distributions of male academy cricketers. Participants included 213 junior cricket players, aged between 9 and 18 years. Players were separated into birth quartiles and also grouped as early, average or late maturers. For the whole cohort, there was a medium effect bias towards players born in BQ1, but the number of early, average and late maturers was as expected. However, there were significantly more early maturers in the U10 and U11 groups than expected, and maturity distributions of the BQ groups showed that there was a small effect size bias towards early maturers in BQ4. Selection biases towards cricketers who are born earlier in the competitive year are consistent from U9 to U16, but more prevalent in the U12 and U14 age groups. There is a bias towards early maturers at U10 and U11, but this reduces as age increases. Practitioners working in academy pathways should be encouraged to assess the maturity status of players to assist in the retention and progression of players. Relative age effects should also be considered, and strategies may be required to identify players born later in the year.

Cancer cell seeding density as a mechanism of chemotherapy resistance: a novel cancer cell density index based on IC50-Seeding Density Slope (ISDS) to assess chemosensitivity.

Although the 50% inhibitory concentration (IC50) is a commonly used measurement of chemosensitivity in cancer cells, it has been known to vary with the density of the treated cells (in that more densely seeded cells are more resistant to chemotherapeutic agents). Indeed, density-dependent chemoresistance may be a significant independent mechanism of therapy resistance. We examine the nature of cell density-dependent chemoresistance and explore possible underlying mechanisms. CellTiter-Glo assays and ethidium homodimer staining revealed that response to chemotherapy is density-dependent in all cancer cell lines tested. Our results prompted us to develop a novel cancer cell seeding density index of chemosensitivity, the ISDS (IC50-Seeding Density Slope), which we propose can serve as an improved method of analyzing how cancer cells respond to chemotherapeutic treatment compared to the widely-used IC50. Furthermore, western blot analysis suggests that levels of autophagy and apoptotic markers are modulated by cancer cell density. Cell viability experiments using the autophagy inhibitor chloroquine showed that chloroquine's efficacy was reduced at higher cell densities and that chloroquine and cisplatin exhibited synergy at both higher and lower cell densities in TOV-21G cells. We discuss alternative mechanisms of density-dependent chemoresistance and in vivo/clinical applications, including challenges of adjuvant chemotherapy and minimal residual disease. Taken together, our findings show that cell density is a significant contributor in shaping cancer chemosensitivity, that the ISDS (aka the Ujwal Punyamurtula/Wafik El-Deiry or Ujwal-WAF Index) can be used to effectively assess cell viability and that this phenomenon of density-dependent chemoresistance may be leveraged for a variety of biologic and cancer therapeutic applications.

Numb regulates Tau levels and prevents neurodegeneration in tauopathy mouse models.

Accumulation of the microtubule-associated protein Tau is linked to neuronal cell death in tauopathies, but how intraneuronal Tau levels are regulated in health and disease remains unclear. Here, we show that conditional inactivation of the trafficking adaptor protein Numb in retinal ganglion cells (RGCs) increases Tau levels and leads to axonal blebbing, which is followed by neuronal cell loss in aged mice. In the TauP301S mouse model of tauopathy, conditional inactivation of Numb in RGCs and spinal motoneurons accelerates neurodegeneration, and loss of Numb in motoneurons also leads to precocious hindlimb paralysis. Conversely, overexpression of the long isoform of Numb (Numb-72) decreases intracellular Tau levels and reduces axonal blebbing in TauP301S RGCs, leading to improved electrical activity in cultured neurons and improves performance in a visually guided behavior test in vivo. These results uncover Numb as a key regulator of intracellular Tau levels and identify Numb-72 as a potential therapeutic factor for tauopathies.

Medical Comorbidities and Medication Use Among Homeless Adults Seeking Mental Health Treatment.

Little is known about the medical conditions and medication use of individuals who are homeless and have mental health problems. This study used secondary data (N = 933) from a mental health clinic serving homeless adults. Primary outcomes were the number and types of self-reported medical conditions and medications. About half (52.60%) of participants were taking one or more medications (mean = 1.67; SD = 2.30), most commonly antidepressants, antipsychotics, and anticonvulsants. Most frequently reported medical conditions were headaches/migraines, hypertension, and arthritis with a mean of 3.09 (SD = 2.74) conditions. Age and sex were significant predictors of the number of medical conditions. Age and the length of time homeless were significant predictors of the number of medications taken. Results suggest that those who are older and have been homeless longer appear to be increased risk for health problems and may need more medications to manage these conditions.

Behavioral and subjective effects of marijuana following partial sleep deprivation.

This study tested whether performance would be more impaired when marijuana use followed partial sleep deprivation (PSD) than when marijuana use followed a typical night of sleep. Seven recreational marijuana users (mean 15 of last 30 days) completed six test sessions in a double-blind randomized within-subject design. Each session began with an overnight stay in a sleep laboratory. Bed and wake times were calculated from mean data on individual sleep diaries. Time-in-bed was either regular (mean=8.2 h) or shortened (first 65% of regular time-in-bed deprived). At 3 and 5 h after waking, daytime sleepiness was measured with self-report questionnaires and a sleep latency test. Approximately 6.5 h after waking, subjects smoked a marijuana cigarette (0.003, 2, or 3.5% delta-9 tetrahydrocannabinol [THC]). Test batteries were completed 2, 62, and 122 min after smoking ended. Sleepiness was significantly greater following PSD than after regular sleep. Following regular sleep, heart rate increases with active THC doses were comparable, but heart rate with 2% THC was significantly less elevated following PSD. Ratings of "impaired" and "stoned" increased with both THC doses after regular sleep and were further increased with 3.5% THC after PSD. High-potency marijuana increased body sway similarly across sleep conditions. There were no significant effects of marijuana or PSD, alone or in combination, on brake latency. Thus, while PSD increased the dose-dependence of THC effects on heart rate and subjective impairment, it did not enhance the effects of marijuana on standing balance and brake latency.