[Primary culture and identification of rat glomerular microvascular endothelial cells].

The aim of the present study was to establish a simple and efficient method for isolation and culture of primary rat glomerular microvascular endothelial cells in vitro. The bilateral kidneys were taken from 7-10-day old Sprague-Dawley rats, and the renal cortex was separated. Glomeruli were obtained by cutting and continuously passing 200-mesh and 300-mesh sieves. After type IV collagenase digestion for 15-20 min, renal microvascular globules were collected for inoculation and culture. The cultured cells were identified by cell morphology observation and immunocytochemical staining with factor VIII related antigen. The results showed that the renal microvascular globules were irregularly spherical, without cysts, and the capillary loop structure was clear; after 3 days of primary culture, short spindle-shaped cells crawled out around the renal microvascular globules and gradually formed cell colonies, showing an "island-like shape" distribution; 4-5 days later, the cell colonies fused with each other; 6 days later, the cells covered the bottom of the dish, showing a typical monolayer, paving stone-like, mosaic arrangement. The immunocytochemical staining of factor VIII related antigen showed that the cytoplasm was lightly stained brownish red, and factor VIII related antigen-positive rate of cells was nearly 100%. The above results suggested that this study successfully established a method combining continuous screening and collagenase digestion for culture of primary rat glomerular microvascular endothelial cells in vitro. It provides an important tool cell for studying the mechanism of the occurrence and development of diabetic nephropathy.

Derivation of new pluripotent stem cells from human extended pluripotent stem cells with formative features and trophectoderm potential.

Previous studies have demonstrated the existence of intermediate stem cells, which have been successfully obtained from human naive pluripotent stem cells (PSCs) and peri-implantation embryos. However, it is not known whether human extended pluripotent stem cells (hEPSCs) can be directly induced into intermediate stem cells. Moreover, the ability of extra-embryonic lineage differentiation in intermediate stem cells has not been verified. In this issue, we transformed hEPSCs into a kind of novel intermediate pluripotent stem cell resembling embryonic days 8-9 (E8-E9) epiblasts and proved its feature of formative epiblasts. We engineered hEPSCs from primed hPSCs under N2B27-LCDM (N2B27 plus Lif, CHIR, DiH and MiH) conditions. Then, we added Activin A, FGF and XAV939 to modulate signalling pathways related to early humans' embryogenesis. We performed RNA-seq and CUT&Tag analysis to compare with AF9-hPSCs from different pluripotency stages of hPSCs. Trophectoderm (TE), primordial germ cells-like cells (PGCLC) and endoderm, mesoderm, and neural ectoderm induction were conducted by specific small molecules and proteins. AF9-hPSCs transcription resembled that of E8-E9 peri-implantation epiblasts. Signalling pathway responsiveness and histone methylation further revealed their formative pluripotency. Additionally, AF9-hPSCs responded directly to primordial germ cells (PGCs) specification and three germ layer differentiation signals in vitro. Moreover, AF9-hPSCs could differentiate into the TE lineage. Therefore, AF9-hPSCs represented an E8-E9 formative pluripotency state between naïve and primed pluripotency, opening new avenues for studying human pluripotency development during embryogenesis.

A prime editor efficiently repaired human induced pluripotent stem cells with AR gene mutation (c.2710G > A; p. V904M).

Prime Editor (PE) is a precise genome manipulation technology based on the CRISPR-Cas9 system, while its application in human induced pluripotent stem cells (iPSCs) remains limited. Here, we established a repaired hiPS cell line (SKLRMi001-A-1) from hiPSCs with androgen receptor (AR) mutation (c.2710G > A; p.V904M). The repaired iPSC line expressed pluripotency markers, retained normal karyotype, showed the capability of differentiating into three germ layers and was absence of mycoplasma infection. The repaired iPSC line will help to elucidate the mechanism of androgen insensitivity syndrome (AIS) and benefit treatment for AIS in the future.

[Primary culture and identification of mouse brain microvascular endothelial cells].

Objective To develop and establish a simple and repeatable method of primary culture of mouse brain microvascular endothelial cells (BMECs) of relatively high purity. Methods Isolated and cultured from the brain tissue of ICR mice aged 2-3 weeks old, the mouse BMECs were gained through physical fragmentation methods such as cutting up and passing through cell sieve, BSA density gradient centrifugation and chemical enzyme digestion. The digestion time of 1 g/L type II collagenase was strictly controlled within 15-20 minutes. The cultured cells were identified by cell morphological observation and immunocytochemical staining to detect factor VII-associated antigen. Results In 24 hours after seeding, the spindle-shaped or polygon-shaped cells began to migrate from the micro vessel segment and gradually gathered and grew in clusters; after 7 days, the fused cells showed a typical single layer and arranged in the shape of paving stone. VII-associated antigen showed positive in the cytoplasm which was brown red. The purity of microvascular endothelial cells was above 95%. Conclusion We have successfully established a simple and repeatable primary culture method for mouse BMECs of relatively high purity.