bioRxiv Science⌕ Search

bioRxiv · 10.1101/2021.03.04.433320

The enpp4 ectonucleotidase regulates kidney patterning signalling networks in Xenopus embryos

Abstract

The enpp ectonucleotidases regulate lipidic and purinergic signalling pathways by controlling the extracellular concentrations of purines and bioactive lipids. Although both pathways are key regulators of kidney physiology and linked to human renal pathologies, their roles during nephrogenesis remain poorly understood. We previously showed that the pronephros was a major site of enpp expression and now demonstrate an unsuspected role for the conserved vertebrate enpp4 protein during kidney formation in Xenopus. Enpp4 over-expression results in ectopic renal tissues and, on rare occasion, complete mini-duplication of the entire kidney. Enpp4 is required and sufficient for expression of the pronephric markers and regulates the expression of RA, Notch and Wnt pathway members. Enpp4 is a membrane protein that binds, without hydrolyzing, phosphatidylserine and its effects are mediated by the receptor s1pr5, although not via the generation of S1P. Finally, we propose a novel and surprising non-catalytic mechanism by which lipidic signalling regulates nephrogenesis.

Source connections

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Masse, K., Bhamra, S., Paroissin, C., Maneta-Peyret, L., Boue-Grabot, E., Jones, E. A.. 2021-03-05. The enpp4 ectonucleotidase regulates kidney patterning signalling networks in Xenopus embryos. https://doi.org/10.1101/2021.03.04.433320

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

Neural regulation of hatching in amphibians

Many animal embryos hatch in response to threats or opportunities, yet how cue sensing activates hatching is unknown. We screened red-eyed treefrog (Agalychnis callidryas) eggs in the field with small molecules to discover that the neurotransmitter acetylcholine is a key mediator of hatching enzyme release. Using behavioral pharmacology, microscopy, and transcriptional profiling we identify direct cholinergic input on hatching gland cells that triggers enzyme release for egg rupture, and serotonergic transduction of embryonic hypoxia sensing. Independent hypoxia-sensing and mechanosensory predation-detection pathways converge on a hatching decision that elicits acetylcholine-dependent enzyme release and coordinated hatching-specific behavior. Cholinergic regulation of hatching enzyme release is conserved in a distantly related frog and salamander, suggesting a shared ancestral hatching mechanism. These results provide a neural basis for hatching plasticity which may have contributed to the evolution of diverse hatching modes in amphibians.

developmental biology↗

Towards Understanding the Microenvironmental Control of Reindeer Antler Regeneration

Deer antlers are the only mammalian appendages capable of complete periodic regeneration and therefore provide a natural model for investigating mechanisms of skeletal regeneration. However, current knowledge of the structural and molecular characteristics of the regenerative antler microenvironment remains incomplete. Here, we compared antler tip and antler base tissues from Rangifer tarandus (reindeer) with mature metacarpal cortical bone using structural, compositional, histological, and proteomic analyses. Antler tissues exhibited smaller and less crystalline apatite structures, elevated carbonate substitution, and higher organic matrix content compared with metacarpal bone, indicating an immature mineral phase. Antlers also exhibited lower bone mineral density, greater porosity, reduced bone volume fraction, and greater trabecular separation, particularly in central regions, consistent with a dynamic remodeling microenvironment. Histological examination revealed abundant active osteons and extensive osteoid seams in antler tissues, whereas metacarpal bone predominantly comprised mature lamellar bone with limited remodeling activity. Proteomic profiling identified distinct extracellular matrix signatures between antler and metacarpal tissues. Metacarpal bone was enriched in proteins associated with skeletal homeostasis, mechanotransduction, and bone remodeling, whereas antler tissues were enriched in proteins involved in extracellular matrix reorganization, metabolic adaptation, and regeneration. Collectively, these findings indicate that reindeer antlers possess a specialized regenerative skeletal microenvironment characterized by immature mineral organization, active remodeling, and distinct molecular signatures associated with rapid tissue growth. These results provide new insights into the biological basis of mammalian appendage regeneration and may facilitate the development of regenerative strategies for bone repair and skeletal tissue engineering.

developmental biology↗

Endogenous expression of mutant RagC in mice results in early-onset dilated cardiomyopathy with features of the Long-Olsen-Distelmaier syndrome

Dilated cardiomyopathy (DCM) is a severe heart condition often linked to arrhythmias, clots, and heart failure, for which treatments are not yet curative. Recently, de novo mutations in genes encoding components of the Rag GTPase nutrient signaling pathway, particularly in RRAGC, have been found in unrelated patients with a severe, early-onset DCM syndrome called Long-Olsen-Distelmaier. Cancer cell lines, hiPSC-derived cardiomyocytes and zebrafish have been used to study this Ragopathy, but a mammalian model to investigate this syndrome has not been generated. Here, we show that mice engineered to endogenously express mutations in Serine 74 (orthologous to the Serine 75 mutated in patients), exhibit early-onset features of DCM with decreased heart size, fibrosis, diastolic dysfunction and aortic insufficiency, characteristics reminiscent of the human syndrome. Moreover, Rragc-mutant hearts display decreased left ventricular mass and interventricular septum. Endogenous heterozygous expression of Rragc mutant variants result in a milder, sublethal defective physiological cardiac growth with increased systolic and diastolic blood pressure. Mechanistically, active RagC does not cause abnormal increase in cardiomyocyte size, but leads to suppressed transcriptional activity of Tfeb and alterations in cardiomyocyte metabolism. Transcriptional profiling of neonatal mutant hearts reveals multiple signatures of impaired mitochondrial activity. Ex vivo and in vitro analyses of murine cardiomyocyte mitochondria from Rragc-mutant mice show suppressed mitochondrial respiration, disturbed complex IV multimerization and super-complex organization. These data point to abnormal early postnatal heart metabolism by deregulated nutrient - Rag GTPase signaling with a potential molecular explanation to the early onset of DCM in patients with de novo missense mutations in RRAGC, and suggests the relevance of early metabolic interventions in conditions with altered nutrient signaling

developmental biology↗