Author Correction: Lin28 and let-7 regulate the timing of cessation of murine nephrogenesis

The mutual patterning between the developing nephron and its covering tissues-valid reasons to rethink the search for traces left by impaired nephrogenesis

Background

The impairment of nephrogenesis can cause the termination of nephron formation in preterm and low birth weight babies. This leads to oligonephropathy with severe health consequences in later life. Although many clinical parameters are known, surprisingly little information is available regarding the initial damage on the developing nephron. Equally astounding, the first morphological data regarding the specifics of nephron formation in the nephrogenic zone of the fetal human kidney during late gestation has only been published within the past few years. In this context, it was observed that each stage of nephron anlage is surrounded by a specific set of tissues. Although highly relevant for the normal progress of nephron formation, the mutual patterning has not been systematically described.

Results

To contribute, the different stages of nephron anlage in the nephrogenic zone of the fetal human kidney during late gestation were screened by the optical microscope and documented by images. Following this, magnifications (28 × 18 cm) were produced to trace the contours of the developing nephron and its covering tissues. The resulting sketches, almost true to scale, were scanned, edited, and processed by a design program. As a base, first the individual position, size, and shape of the nephrogenic niche, pretubular aggregate, renal vesicles, comma- and S-shaped bodies are presented. Secondly, their structural relations to the renal capsule, collecting duct ampulla, perforating radiate artery, and expanding interstitium are shown. Third of all, the focus is on less considered configurations, such as site-specific approximation, local distancing, punctual adhesion, integration, separation, delamination, formation of congruent and divergent surfaces, and folding and opening of interstitial clefts.

Conclusions

The present contribution illuminates the mutual patterning between the developing nephron and its covering tissues. It is indispensable to know about the microanatomical relations, in order to identify whether the noxae impairing nephrogenesis targets only the developing nephron or also its covering tissues as interacting and controlling instances.

LIN28A inhibits DUSP family phosphatases and activates MAPK signaling pathway to maintain pluripotency in porcine induced pluripotent stem cells

LIN28A, an RNA-binding protein, plays an important role in porcine induced pluripotent stem cells (piPSCs). However, the molecular mechanism underlying the function of LIN28A in the maintenance of pluripotency in piPSCs remains unclear. Here, we explored the function of LIN28A in piPSCs based on its overexpression and knockdown. We performed total RNA sequencing (RNA-seq) of piPSCs and detected the expression levels of relevant genes by quantitative real-time polymerase chain reaction (qRT-PCR), western blot analysis, and immunofluorescence staining. Results indicated that piPSC proliferation ability decreased following LIN28A knockdown. Furthermore, when LIN28A expression in the shLIN28A2 group was lower (by 20%) than that in the negative control knockdown group (shNC), the pluripotency of piPSCs disappeared and they differentiated into neuroectoderm cells. Results also showed that LIN28A overexpression inhibited the expression of DUSP (dual-specificity phosphatases) family phosphatases and activated the mitogen-activated protein kinase (MAPK) signaling pathway. Thus, LIN28A appears to activate the MAPK signaling pathway to maintain the pluripotency and proliferation ability of piPSCs. Our study provides a new resource for exploring the functions of LIN28A in piPSCs.