FOXC2 controls adult lymphatic endothelial specialization, function, and gut lymphatic barrier preventing multiorgan failure.

The mechanisms maintaining adult lymphatic vascular specialization throughout life and their role in coordinating inter-organ communication to sustain homeostasis remain elusive. We report that inactivation of the mechanosensitive transcription factor Foxc2 in adult lymphatic endothelium leads to a stepwise intestine-to-lung systemic failure. Foxc2 loss compromised the gut epithelial barrier, promoted dysbiosis and bacterial translocation to peripheral lymph nodes, and increased circulating levels of purine metabolites and angiopoietin-2. Commensal microbiota depletion dampened systemic pro-inflammatory cytokine levels, corrected intestinal lymphatic dysfunction, and improved survival. Foxc2 loss skewed the specialization of lymphatic endothelial subsets, leading to populations with mixed, pro-fibrotic identities and to emergence of lymph node-like endothelial cells. Our study uncovers a cross-talk between lymphatic vascular function and commensal microbiota, provides single-cell atlas of lymphatic endothelial subtypes, and reveals organ-specific and systemic effects of dysfunctional lymphatics. These effects potentially contribute to the pathogenesis of diseases, such as inflammatory bowel disease, cancer, or lymphedema

Astrocytes grown in Alvetex® 3 dimensional scaffolds retain a non-reactive phenotype

yesProtocols which permit the extraction of primary astrocytes from either embryonic or postnatal mice are well established however astrocytes in culture are different to those in the mature CNS. Three dimensional (3D) cultures, using a variety of scaffolds may enable better phenotypic properties to be developed in culture. We present data from embryonic (E15) and postnatal (P4) murine primary cortical astrocytes grown on coated coverslips or a 3D polystyrene scaffold, Alvetex. Growth of both embryonic and postnatal primary astrocytes in the 3D scaffold changed astrocyte morphology to a mature, protoplasmic phenotype. Embryonic-derived astrocytes in 3D expressed markers of mature astrocytes, namely the glutamate transporter GLT-1 with low levels of the chondroitin sulphate proteoglycans, NG2 and SMC3. Embroynic astrocytes derived in 3D show lower levels of markers of reactive astrocytes, namely GFAP and mRNA levels of LCN2, PTX3, Serpina3n and Cx43. Postnatal-derived astrocytes show few protein changes between 2D and 3D conditions. Our data shows that Alvetex is a suitable scaffold for growth of astrocytes, and with appropriate choice of cells allows the maintenance of astrocytes with the properties of mature cells and a non-reactive phenotype.BBSR

Function of the Evx-2 gene in the morphogenesis of vertebrate limbs

Vertebrate gene members of the HoxD complex are essential for proper development of the appendicular skeletons. Inactivation of these genes induces severe alterations in the size and number of bony elements. Evx-2, a gene related to the Drosophila even-skipped (eve) gene, is located close to Hoxd-13 and is expressed in limbs like the neighbouring Hoxd genes. To investigate whether this tight linkage reflects a functional similarity, we produced a null allele of Evx-2. Furthermore, and because Hoxd-13 function is prevalent over that of nearby Hoxd genes, we generated two different double mutant loci wherein both Evx-2 and Hoxd-13 were inactivated in cis. The analysis of these various genetic configurations revealed the important function of Evx-2 during the development of the autopod as well as its genetic interaction with Hoxd-13. These results show that, in limbs, Evx-2 functions like a Hoxd gene. A potential evolutionary scenario is discussed, in which Evx-2 was recruited by the HoxD complex in conjunction with the emergence of digits in an ancestral tetrapod