Stem cells are a kind of specialized cell type with the ability of self-renewal and multilineage differentiation potential. They can proliferate and differentiate into many other cell types under a specific condition. However, proliferation and differentiation behaviors of stem cells depend on their located microenvironment, which is also named stem cell niche. An appropriate spatiotemporal dialog occurs between stem cells and niche to fulfill the balance of their self-renewal and differentiation. This review focused on several different stem cell niches and their relationship with proliferation and differentiation of stem cells.
Cell Differentiation ; Cell Proliferation ; Humans ; Stem Cell Niche ; physiology ; Stem Cells ; cytology ; physiology

OBJECTIVE: This study aimed to investigate the effect of calcium ion (Ca²⁺) on the migration and osteogenic differentiation of human osteoblasts and explore the proper concentration and correlation mechanism. METHODS: A series of Ca²⁺ solutions with different concentrations was prepared. Osteoblast migration was assessed by Transwell assay, and proliferation was studied via the CCK-8 colorimetric assay. The mRNA expression of osteogenic genes was examined via reverse transcription-polymerase chain reaction (RT-PCR), and the mineralized nodule was examined by alizarin red-S method. After calcium sensitive receptor (CaSR) antagonism, Ca²⁺-induced migration and osteogenic differentiation were analyzed. RESULTS: In the migration experiment, 2, 4, and 6 mmol·L⁻¹ Ca²⁺ could promoted osteoblast migration at three timepoints (8, 16, and 24 h), whereas 10 mmol·L⁻¹ Ca²⁺ considerably inhibited migration at 8 h. The Ca²⁺ concentration range of 2-10 mmol·L⁻¹ could promote proliferation, osteogenic differentiation, and mineralization of human osteoblasts. Moreover, mineralization was predominantly induced by 8 and 10 mmol·L⁻¹ Ca²⁺. CaSR antagonism could reduce Ca²⁺-induced migration and osteogenic differentiation of human osteoblasts. CONCLUSIONS Low Ca²⁺ concentration favored osteoblast migration, whereas high Ca²⁺ concentration favored osteogenic differentiation. The Ca²⁺ concentrations of 4 and 6 mmol·L⁻¹ could substantially induce osteoblast migration and osteogenic differentiation, and the Ca²⁺-CaSR pathway participated in signal transduction.
Calcium ; physiology ; Cell Differentiation ; Cell Movement ; Cell Proliferation ; Humans ; Osteoblasts ; Osteogenesis ; physiology ; Signal Transduction

The normal range of oral mucosal cell apoptosis and proliferation rate through a larger sample of non-malnourished crowd was investigated, and the nutritional status of clinical patients was assessed. Of 194 clinical patients selected according to "NRS2002" guidance, there were 167 non-malnourished patients and 27 malnourished cases, respectively. Twelve patients with toxic reactions of grade III after postoperative chemotherapy (POC) were chosen. The oral mucosal epithelial apoptosis and proliferation rate were measured by using flow cytometry. The statistical significance was processed by using unpaired t-test. The results showed that there was no significant difference in gender, age and body weight between malnourished and non-malnourished groups. The normal range of oral mucosal epithelial apoptosis and the proliferation rate was (27.50±1.50)% and (15.12±1.68)% in non-malnourished patients, and that was (19.90±4.14)% and (6.66±5.83)% in the malnourished patients, respectively. It is concluded that the normal range of oral mucosa cell apoptosis and proliferation rate is achieved, which can not be influenced by gender, age, weight and other factors, and could be used as a sensitive and accurate index to assess the nutritional status of clinical patients.
Apoptosis ; physiology ; Cell Proliferation ; Female ; Humans ; Male ; Middle Aged ; Mouth Mucosa ; pathology ; physiology ; Nutritional Status ; physiology

Nephronectin (NPNT) is a novel extracellular matrix protein and a new ligand of integrin α8β1. Recent studies showed that NPNT is highly expressed in kidney, lung, thyroid, etc, and it may play an important role in many pathological conditions. NPNT is involved in the process of kidney development and acute kidney injury, regulates proliferation and differentiation of osteoblast, and induces the vasculogenesis in vitro. NPNT may play a key role in pathological osteoporosis and therefore be a new therapeutic target of bone diseases. NPNT gene variants are not only associated with lung function, but also potentially implicated in chronic airway diseases development. Moreover, NPNT is also an important factor that mediates pathology of cardiac, epidermis, breast, liver and teeth diseases. In this paper, we reviewed some research progresses on the structure, distribution, physiological and pathophysiological functions of NPNT.
Cell Differentiation ; Cell Proliferation ; Extracellular Matrix Proteins ; physiology ; Humans ; Kidney ; physiology ; Osteoblasts ; cytology ; Osteoporosis

OBJECTIVETo explore the effects and mechanism of mesangial cell (MC) on proliferation and function of osteoblast in vitro from growth factors.

METHODSOsteoblast cultured in vitro were divided into normal blood serum group and MC group and cultured supernatant fluid by 10% serum culture medium and 20% MC culture medium. MTF was used to checked the proliferation of osteoblast at the end of 24, 48, 72, 120 h; Expression of BGP and OPN were tested 72 h and 144 h after culture; Expression of IGF-alpha and TGF-beta were tested 144 h after culture.

RESULTSThe proliferation of osteoblast in MC group was obviously higher than normal blood serum group in different times (P < 0.05); The level of BGP and OPN of osteoblast was obviously higher than normal blood serum group (11.3%, 16.4%, 55.0% and 39.6%); and the level of IGF-alpha and TGF-beta of osteoblast was obviously higher than normal blood serum group (10.1% and 47.7%).

CONCLUSIONMC can directly act on osteoblast, promote the proliferation and function of osteoblast by promoting secretion of TGF-beta.

Animals ; Cell Proliferation ; Male ; Mesangial Cells ; physiology ; Osteoblasts ; physiology ; Osteopontin ; physiology ; Rats ; Rats, Sprague-Dawley ; Transforming Growth Factor beta ; physiology

Mechanics plays an important role in regulating cell function. Hydrodynamics has become a hot topic of research in recent years. As an important factor, hydrodynamic pressure has significant influence on the form, cytoskeleton, proliferation, apoptosis and secretion function of cells. Many researches indicated that there are close relationships between kidney diseases and hydrodynamics which should be studied deeply.
Apoptosis ; physiology ; Cell Proliferation ; Cytoskeleton ; physiology ; Humans ; Hydrodynamics ; Hydrostatic Pressure ; Kidney ; cytology ; Pressure

Hippo signaling pathway is highly conservative in evolution. MST1/2, LATS1/2, and the effector protein YAP/TAZ are the core members of this signaling pathway in mammalian cells. There have been many studies on YAP/TAZ and its downstream, however, the upstream regulatory factors of the Hippo signaling pathway remain unclear, and become one of the hot research directions of this pathway at present. In addition, Hippo signaling pathway can cross-talk with other signaling pathways such as Wnt and Notch signaling pathways, and plays an important role in controlling organ size, maintaining tissue homeostasis, and promoting tissue repair and regeneration. Abnormal Hippo signaling pathway may lead to the occurrence of a variety of tumors, especially gastrointestinal cancers such as liver cancer, colorectal cancer and gastric cancer. The abnormal expression of its members in gastrointestinal cancers is related to cancer cell proliferation, apoptosis, invasion and migration. Hippo signaling pathway is vital for liver repair and regeneration. Its inactivation will lead to the occurrence of primary liver cancer. The mechanism of YAP in liver cancer mainly depends on TEAD-mediated gene transcription. Hippo signaling pathway is also important for maintaining intestinal homeostasis, and its imbalance can lead to the occurrence and recurrence of colorectal cancer. In primary and metastatic gastric cancer, the expression of YAP/TAZ is significantly up-regulated, but the specific molecular mechanism is unclear. This article summarizes the recent progress on Hippo signaling pathway and its upstream regulatory factors, its roles in the development of gastrointestinal cancers and related molecular mechanisms; and also discusses the future research directions of Hippo signaling pathway.
Apoptosis ; physiology ; Cell Proliferation ; physiology ; Gastrointestinal Neoplasms ; physiopathology ; Humans ; Signal Transduction

AIMTo explore the effects of tRNA on the growth of mammalian cells.

METHODSL929, NIH3T3, MCF-7 and PC12 cells were seeded in 96 well culture plate individually, and incubated at 37 degrees C in 5% CO2 for 4 h, the tRNAs from different species were added to the culture media individually. After certain time of incubation, the viability of the cells was evaluated by the MTT methods. Sub-confluent L929 cells were incubated with 200 microg/ml ytRNA for different times, then the cells were pooled and analyzed with flow cytometry assay.

RESULTStRNA specifically inhibited the growth of L929 cells in a dose-dependent manner. The sizes of tRNA-treated cells showed larger sizes and longer processes than those of untreated cells. Flow cytometric analysis further showed that most of tRNA-treated cells were arrested in S phase of the cell cycle.

CONCLUSIONThe cell growth inhibitory effects of tRNAs were caused mainly by their degraded fragments. The results suggested that tRNA or its degraded fragments might play important roles in regulation of cell proliferation.

Animals ; Cell Cycle Checkpoints ; physiology ; Cell Line ; Cell Proliferation ; Fibroblasts ; cytology ; Flow Cytometry ; Mice ; RNA, Transfer ; physiology

Nucleotides have unambiguously emerged as a family of mediators of intercellular communication, which bind a class of plasma membrane receptors, P2 purinergic receptors, to trigger intercellular signaling. P2 receptors can be further divided into two structurally and functionally different sub-famlies, the P2X and P2Y receptors. Different blood cells express diverse spectrum of P2 receptors at different levels. Extracellular adenosine triphosphate (ATP) exerts different effects on blood cells, regulating cell proliferation, differentiation, migration, chemotaxis, release of cytokines or lysosomal constituents, and generation of reactive oxygen or nitrogen species. The relationship between abnormal P2 receptors and human diseases attracts more and more attention. This review briefly discusses the expression and function of P2 receptors in hematopoietic system.
Adenosine Triphosphate ; Blood Cells ; physiology ; Cell Differentiation ; Cell Movement ; Cell Proliferation ; Hematopoiesis ; Humans ; Receptors, Purinergic P2 ; physiology ; Signal Transduction

This study examined the biological characteristics of normal and degenerated rabbit nucleus pulposus (NP) cells in vitro in order to provide seed cells for intervertebral disc (IVD) tissue engineering. A total of 8 adult New Zealand white rabbits underwent annulus puncture to establish models of intervertebral disc degeneration (IDD). Four weeks later, normal and degenerated NP cells were obtained. Cell morphology was observed by light and electron microscopy. Cell viability was measured by MTT assay. Cell cycle and expression of extracellular matrix (ECM)-related genes (aggrecan and type II collagen) were determined by using flow cytometry and RT-PCR respectively. The growth curve of normal NP cells showed that the cells at passage 4 tended to slowly grow on the fifth day of culture. The density of normal NP cells at passages 5 to 7 was significantly less than that of the first-passage cells 2 or 3 days after seeding (P<0.05). The degenerated NP cells at passage 3 showed slow growth at 4th day. After 5 passages, the degenerated NP cells assumed stagnant growth and the growth seemed to stop at passage 7. The MTT assay revealed that for both normal and degenerated NP cells, the absorbance (A) value at passages 4-7 was obviously decreased as compared with that at passage 1 (P<0.05). Cell cycle analysis showed that the proportion of normal NP cells at Gl phase was 65.4%±3.5%, significantly lower than that of degenerated NP cells at the same cell cycle phase with the value being 77.6%±4.8%. The degenerated NP cells were predominantly arrested at G1 phase and failed to enter S phase. The expression of type II collagen and aggrecan was significantly decreased with passaging. It was concluded that normal NP cells possessed good viability and proliferative capacity by the third passage, and they could secrete large amounts of ECM within this period. The normal NP cells may serve as seed cells for IVD tissue engineering.
Animals ; Apoptosis ; physiology ; Cell Cycle ; physiology ; Cell Proliferation ; Cell Size ; Cell Survival ; physiology ; Cells, Cultured ; Intervertebral Disc ; cytology ; physiopathology ; Intervertebral Disc Degeneration ; pathology ; physiopathology ; Rabbits ; Reference Values