Inversin (NPHP2) and Vangl2 are required for normal zebrafish cloaca formation.

Nephronophthisis (NPH), an autosomal recessive ciliopathy, results from mutations in more than 20 different genes (NPHPs). These gene products form protein complexes that regulate trafficking within the cilium, a microtubular structure that plays a crucial role in developmental processes. Several NPHPs, including NPHP2/Inversin, have been linked to extraciliary functions. In addition to defining a specific segment of primary cilia (Inversin compartment), NPHP2 participates in planar cell polarity (PCP) signaling along with Dishevelled and Vangl family members. We used the mutant zebrafish line invssa36157, containing a stop codon at amino acid 314, to characterize tissue-specific functions of zebrafish Nphp2. The invssa36157 line exhibits mild ciliopathy phenotypes and increased glomerular and cloaca cyst formation. These mutants showed enhanced susceptibility to the simultaneous depletion of the nphp1/nphp2/nphp8 module, known to be involved in the cytoskeletal organization of epithelial cells. Notably, simultaneous depletion of zebrafish nphp1 and vangl2 led to a pronounced increase in cloaca malformations in the invssa36157 mutant embryos. Time-lapse imaging showed that the pronephric cells correctly migrated towards the ectodermal cells in these embryos, but failed to form the cloaca opening. Despite these abnormal developments, cellular fate does not seem to be affected in nphp1 and vangl2 MO-depleted invssa36157 mutants, as shown by in situ hybridizations for markers of pronephros and ectodermal cell development. However, significantly reduced apoptotic activity was observed in this double knockdown model, signifying the role of apoptosis in cloacal morphogenesis. Our findings underscore the critical interplay of nphp1, nphp2/Inversin, and vangl2 in orchestrating normal cloaca formation in zebrafish, shedding light on the complex molecular mechanisms underlying ciliopathy-associated phenotypes.

Objectively Measured Physical Activity and Sedentary Time of Suburban Toddlers Aged 12-36 Months.

Low levels of physical activity may predispose children to the development of obesity and related chronic diseases in later life. The aims of this study were as follows: (1) quantitatively describe the levels of habitual physical activity in a contemporary sample of suburban children aged 12 to 36 months; (2) assess for gender differences in physical activity and sedentary behavior; (3) examine the specific effects of ethnicity, gender and overweight status on the objectively measured physical activity; and (4) quantify the tracking of physical activity in a subset of children over 1 year. During year one, 142 participants wore the GT3X Actigraph for 3 days. At a 1-year follow-up, a subset of 25 participants wore the Actigraph for 7 consecutive days. GLM and t-tests as appropriate were carried out to assess the influence of gender on the physical activity level. Spearman rank correlations, percentage agreement and kappa statistics assessed the tracking of physical activity. The results showed no significant gender differences in any anthropometric measurements, sedentary behavior or MVPA (p > 0.05). There were also no significant gender, ethnicity or overweight interaction for sedentary behavior, time spent in light PA and time spent in MVPA (p > 0.05). For tracking, there was a moderate strength of agreement for MVPA. Considering the disproportionate effects of obesity in minority groups, culturally appropriate interventions targeting the reduction in sedentary behavior are urgently required.