Co-exposure to cannabis and nicotine during pregnancy alters fetal lung development

Abstract

Rationale: The co-use of cigarettes and cannabis is increasing especially in regions where recreational marijuana use has become legal. However, the use of these dependent substances during pregnancy poses a serious risk on fetal development and health (low birth weight, preterm birth, and perinatal death). Nevertheless, the impact of co-exposure to the most prominent cannabinoids found in Cannabis sativa (Trans-Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD)) with nicotine on fetal lung development is not well understood. This study aims to determine the effect of nicotine, CBD, and THC, alone or combined, on human lung development through investigating cellular senescence. Methods: In vitro human fetal lung explants from 10–20 weeks gestation were cultured on air-liquid interface and treated with physiological concentrations of CBD, THC, and nicotine, alone or combined, for 72h. Similarly, lung mesenchymal cells (LMCs) were isolated from the same samples and treated for 48h. Both culture types were either fixed for immunofluorescent staining or used for RNA extraction and qRT-PCR. Results: Our results showed that nicotine and CBD induce thickening of the mesenchymal compartment of lung explants. Furthermore, treatment with either CBD or THC, or the two combined, induced an increase in epithelial cysting. Ki-67 staining demonstrated increased proliferation following treatment with nicotine, THC and CBD+THC+nicotine. ACTA2 staining, a marker for smooth muscle cells, decreased following treatment with THC, CBD, and nicotine as well as all 3 combined, while the senescence marker p21 increased following exposure to nicotine, CBD+THC, as well as CBD+THC+nicotine. qRT-PCR data showed decreased expression of ACTA2 in the presence of CBD, THC, CBD+THC, and CBD+THC+nicotine, and increased expression of CDKN1A (encoding p21) and CDKN2A (encoding p16) in response to CBD+THC+nicotine. LMCs treated with nicotine, CBD, and THC demonstrated an increase in cell proliferation and senescence as shown by Ki-67 and p21 staining respectively, and a decrease in ACTA2. These data were confirmed by qRT-PCR that showed a decrease in ACTA2 for the LMCs treated with either nicotine or CBD+THC+nicotine and an increase in senescence genes CDKN1A and CDKN2A. Moreover, the expression of these genes was higher in the LMCs derived from second trimester samples in comparison to those of the first trimester. Conclusion: Our results showed that the co-exposure to nicotine and cannabis induces senescence and alters lung fetal cellular proliferation, especially when used in conjunction. Furthermore, this effect appears to be age dependent. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.