Engineering of human mesenchymal stem cells resistant to multiple natural killer subtypes.

Mesenchymal stem cells (MSCs) as a therapeutic promise are often quickly cleared by innate immune cells of the host including natural killer (NK) cells. Efforts have been made to generate immune-escaping human embryonic stem cells (hESCs) where T cell immunity is evaded by defecting ß-2-microglobulin (B2M), a common unit for human leukocyte antigen (HLA) class I, and NK cells are inhibited via ectopic expression of HLA-E or -G. However, NK subtypes vary among recipients and even at different pathologic statuses. It is necessary to dissect and optimize the efficacy of the immune-escaping cells against NK subtypes. Here, we first generated B2M knockout hESCs and differentiated them to MSCs (EMSCs) and found that NK resistance occurred with B2M-/- EMSCs expressing HLA-E and -G only when they were transduced via an inducible lentiviral system in a dose-dependent manner but not when they were inserted into a safe harbor. HLA-E and -G expressed at high levels together in transduced EMSCs inhibited three major NK subtypes, including NKG2A+ /LILRB1+ , NKG2A+ /LILRB1- , and NKG2A- /LILRB1+ , which was further potentiated by IFN-γ priming. Thus, this study engineers MSCs with resistance to multiple NK subtypes and underscores that dosage matters when a transgene is used to confer a novel effect to host cells, especially for therapeutic cells to evade immune rejection.

Liver Fibrosis Can Be Induced by High Salt Intake through Excess Reactive Oxygen Species (ROS) Production.

High salt intake has been known to cause hypertension and other side effects. However, it is still unclear whether it also affects fibrosis in the mature or developing liver. This study demonstrates that high salt exposure in mice (4% NaCl in drinking water) and chick embryo (calculated final osmolality of the egg was 300 mosm/L) could lead to derangement of the hepatic cords and liver fibrosis using H&E, PAS, Masson, and Sirius red staining. Meanwhile, Desmin immunofluorescent staining of mouse and chick embryo livers indicated that hepatic stellate cells were activated after the high salt exposure. pHIS3 and BrdU immunohistological staining of mouse and chick embryo livers indicated that cell proliferation decreased; as well, TUNEL analyses indicated that cell apoptosis increased in the presence of high salt exposure. Next, dihydroethidium staining on the cultured chick hepatocytes indicated the excess ROS was generated following high salt exposure. Furthermore, AAPH (a known inducer of ROS production) treatment also induced the liver fibrosis in chick embryo. Positive Nrf2 and Keap1 immunohistological staining on mouse liver suggested that Nrf2/Keap1 signaling was involved in high salt induced ROS production. Finally, the CCK8 assay was used to determine whether or not the growth inhibitory effect induced by high salt exposure can be rescued by antioxidant vitamin C. Meanwhile, the RT-PCR result indicated that the Nrf2/Keap1 downsteam genes including HO-1, NQO-1, and SOD2 were involved in this process. In sum, these experiments suggest that high salt intake would lead to high risk of liver damage and fibrosis in both adults and developing embryos. The pathological mechanism may be the result from an imbalance between oxidative stress and the antioxidant system.

Role of Slit2/Robo1 in trophoblast invasion and vascular remodeling during ectopic tubal pregnancy.

INTRODUCTION: For ectopic tubal pregnancy to be viable, it requires a supporting vascular network and functioning trophoblast. Slit2/Robo1 signaling plays an important role in placental angiogenesis during normal pregnancy. Hence, we here investigated whether or not Slit2/Robo1 signaling also had an impact in ectopic tubal pregnancy. METHODS: The Slit2 and Robo1 expression pattern relevant to trophoblast invasive behavior and vascular remodeling was studied in human tubal placenta obtained from patients with ectopic pregnancy (5-8weeks gestation), The trophoblast development, vascular architecture and Robo1 expression pattern were observed in Slit2 overexpression (Slit2-Tg) and C57BL mice placenta (E13.5 and E15.5). RESULTS: Marked with CK-7 and Vimentin, the vessel profiles of fallopian tube were classified into four stages. In the presence of extravillous trophoblast (EVT), stellate-shaped and polygonal-shaped EVTs were observed, and the stellate-shaped EVT showed the higher Slit2 expression (P < 0.01) but lower Robo1 expression (P < 0.05) than polygonal-shaped cells. By contrast, a temporary Slit2 up-regulation in remodeling vessel and Slit2 down-regulation in remodeled vessel of polygonal-shape extravillous trophoblast cells occurred in tubal pregnancies. In Slit2-Tg mice E13.5 and E15.5 placenta, Slit2 overexpression promoted vascular remodeling by increasing in the diameter of the maternal blood sinusoids and fetal capillaries, but enhanced the thickness of trophoblast and vasculature at E15.5 Slit2-Tg mice. CONCLUSIONS: The varying Slit2 and Robo1 expression in EVTs was associated with trophoblast invasion and probably plays an important role in the events of blood vessel remodeling of the fallopian tube tissues.

High salt intake negatively impacts ovarian follicle development.

Many human disorders induce high salinity in tissues and organs, interfering with their normal physiological functions. Using a mouse model, we demonstrated that high salt intake caused infertility. Specifically, we established that high salinity dramatically affects ovarian follicle development and the extent of follicular atresia. However, it did not significantly influence the primordial follicles. TUNEL assays revealed that high salt intake inhibited follicle development by inducing the granulosa and theca cells that surround the oocytes to undergo apoptosis. Furthermore, immunohistological staining for the proliferation markers Ki67 and PH3 showed that high salt intake also repressed granulosa cell proliferation. In vitro testing of granulosa cells also confirmed that high salt significantly repressed cell proliferation and promoted cell apoptosis. In summary, high salt consumption negatively impacts reproductive functions in female mice by interfering with ovarian folliculogenesis.