Dolutegravir Impairs Stem Cell-Based 3D Morphogenesis Models in a Manner Dependent on Dose and Timing of Exposure: An Implication for Its Developmental Toxicity.

Dolutegravir (DTG) is an antiretroviral drug of the integrase strand transfer inhibitor (INSTI) class used to treat human immunodeficiency virus infection. It is the recommended first-line regimen for most people, including women of childbearing age. However, some human and animal studies have suggested that DTG causes birth defects, although its developmental toxicity remains controversial. Here, we investigated the adverse effects of DTG using pluripotent stem cell-based in vitro morphogenesis models that have previously been validated as effective tools to assess the developmental toxicity of various chemicals. DTG diminished the growth and axial elongation of the morphogenesis model of mouse pluripotent stem cells at exposures of 2 µM and above in a concentration-dependent manner. Concomitantly, DTG altered the expression profiles of developmental regulator genes involved in embryonic patterning. The adverse effects were observed when the morphogenesis model was exposed to DTG at early stages of development, but not at later stages. The potency and molecular impact of DTG on the morphogenesis model were distinct from other INSTIs. Last, DTG altered the growth and gene expression profiles of the morphogenesis model of human embryonic stem cells at 1 µM and above. These studies demonstrate that DTG impairs morphological and molecular aspects of the in vitro morphogenesis models in a manner dependent on dose and timing of exposure through mechanisms that are unrelated to its action as an INSTI. This finding will be useful for interpreting the conflicting outcomes regarding the developmental toxicity of DTG in human and animal studies.

Stratified layer analysis reveals intrinsic leptin stimulates cryptal mesenchymal cells for controlling mucosal inflammation.

Mesenchymal cells in the crypt play indispensable roles in the maintenance of intestinal epithelial homeostasis through their contribution to the preservation of stem cells. However, the acquisition properties of the production of stem cell niche factors by the mesenchymal cells have not been well elucidated, due to technical limitations regarding the isolation and subsequent molecular and cellular analyses of cryptal mesenchymal cells. To evaluate the function of mesenchymal cells located at the large intestinal crypt, we established a novel method through which cells are harvested according to the histologic layers of mouse colon, and we compared cellular properties between microenvironmental niches, the luminal mucosa and crypts. The gene expression pattern in the cryptal mesenchymal cells showed that receptors of the hormone/cytokine leptin were highly expressed, and we found a decrease in Wnt2b expression under conditions of leptin receptor deficiency, which also induced a delay in cryptal epithelial proliferation. Our novel stratified layer isolation strategies thus revealed new microenvironmental characteristics of colonic mesenchymal cells, including the intrinsic involvement of leptin in the control of mucosal homeostasis.