NHE1/SLC9A1 is a ubiquitous isoform of vertebrate Na+/H+ exchangers (NHEs) functioning in maintaining intracellular concentrations of Na+ and H+ ions. Calcineurin homologous protein-1 (CHP1) binds to the hydrophilic region of NHE1 and regulates NHE1 activity but reportedly does not play a role in translocating NHE1 from the endoplasmic reticulum to the plasma membrane. However, an antiport function of NHE1 requiring CHP1 remains to be clarified. Here we established CHP1-deficient chicken B lymphoma DT40 cells by gene targeting to address CHP1 function. CHP1-deficient cells showed extensive decreases in Na+/H+ activities in intact cells. Although NHE1 mRNA levels were not affected, NHE1 protein levels were significantly reduced not only in the plasma membrane but in whole cells. The expression of a CHP1 transgene in CHP1-deficient cells rescued NHE1 protein expression. Expression of mutant forms of CHP1 defective in Ca2+ binding or myristoylation also partially decreased NHE1 protein levels. Knockdown of CHP1 also caused a moderate decrease in NHE1 protein in HeLa cells. These data indicate that CHP1 primarily plays an essential role in stabilization of NHE1 for reaching of NHE1 to the plasma membrane and its exchange activity. membrane protein; transporter; antiporter; quality control; degradation 相似文献
Cells in the white matter of the adult brain have a characteristic distribution pattern in which several cells are contiguously connected to each other, making a linear array (LA) resembling pearls-on-a-string parallel to the axon axis. We have been interested in how this pattern of cell distribution changes during aging and remyelination after demyelination. In the present study, with a multiplex staining method, semi-quantitative analysis of the localization of oligodendrocyte lineage cells (oligodendrocyte progenitors, premyelinating oligodendrocytes, and mature oligodendrocytes), astrocytes, and microglia in 8-week-old (young adult) and 32-week-old (aged) corpus callosum showed that young adult cells still include immature oligodendrocytes and that LAs contain a higher proportion of microglia than isolated cells. In aged mice, premyelinating oligodendrocytes were decreased, but microglia continued to be present in the LAs. These results suggest that the presence of microglia is important for the characteristic cell localization pattern of LAs. In a cuprizone-induced demyelination model, we observed re-formation of LAs after completion of cuprizone treatment, concurrent with remyelination. These re-formed LAs again contained more microglia than the isolated cells. This finding supports the hypothesis that microglia contribute to the formation and maintenance of LAs. In addition, regardless of the distribution of cells (LAs or isolated cells), astrocytes were found to be more abundant than in the normal corpus callosum at 24 weeks after cuprizone treatment when remyelination is completed. This suggests that astrocytes are involved in maintaining the functions of remyelinated white matter.
Homeostatic regulation of epidermal keratinocytes is controlled by the local cytokine milieu. However, a role for suppressor of cytokine signaling (SOCS), a negative feedback regulator of cytokine networks, in skin homeostasis remains unclear. Keratinocyte specific deletion of Socs3 (Socs3 cKO) caused severe skin inflammation with hyper-production of IgE, epidermal hyperplasia, and S100A8/9 expression, although Socs1 deletion caused no inflammation. The inflamed skin showed constitutive STAT3 activation and up-regulation of IL-6 and IL-20 receptor (IL-20R) related cytokines, IL-19, IL-20 and IL-24. Disease development was rescued by deletion of the Il6 gene, but not by the deletion of Il23, Il4r, or Rag1 genes. The expression of IL-6 in Socs3 cKO keratinocytes increased expression of IL-20R-related cytokines that further facilitated STAT3 hyperactivation, epidermal hyperplasia and neutrophilia. These results demonstrate that skin homeostasis is strictly regulated by the IL-6-STAT3-SOCS3 axis. Moreover, the SOCS3-mediated negative feedback loop in keratinocytes has a critical mechanistic role in the prevention of skin inflammation caused by hyperactivation of STAT3. 相似文献
A serum factor preparation extensively purified from bovine serum stimulated cathepsin D-release from the rat blood cells in a concentration-dependent fashion within a range of physiological concentrations of the factor. Among the blood cells only the erythrocytes (or ghosts) were responsive to the factor, and the leucocytes and lymphocytes were unresponsive. The effects of Ca2+-concentrations, SH- blocking reagents, protease-inhibitors, calmodulin-inhibitors, calmodulin or EGTA-pretreatment of the ghosts on cathepsin D-release from the erythrocytes of ghosts in the presence or the absence of serum factor were investigated. The results suggested that the serum factor may first activate the Ca2+-calmodulin system via the mobilization of "Ca2+-pool" and then the calmodulin-dependent SH-protease in the erythrocyte plasma membranes. The activated protease in turn may break the linkage between cathepsin D and the plasma membranes, liberating cathepsin D activity into the incubation medium. The name of "calciferin" was proposed for the serum factor. 相似文献
The purpose of this study was to clarify the characteristic child-rearing problems for mothers of multiple children who conceived after infertility treatment as compared to mothers of multiple children who conceived spontaneously. The subjects were 990 mothers of multiple children: 359 who conceived after infertility treatment and 631 who conceived spontaneously. Mothers who conceived after infertility treatment were more delighted when informed of a multiple pregnancy than those who conceived spontaneously. In addition, with respect to anxiety during twin pregnancies, mothers of twins who conceived after infertility treatment showed lower rates of anxiety about nursing the infants and economic concerns than those of twins who conceived spontaneously. However, after delivery, mothers who conceived after infertility treatment showed a higher rate of depressive symptoms than those who conceived spontaneously. After adjusting for each associated factor using logistic regression, the risk of depressive symptoms in mothers who conceived after infertility treatment was significantly associated with disabled multiple children and the methods for alleviating stress. The odds ratio indicated that mothers with at least one disabled child were twice as likely to have depressive symptoms as mothers with no disabled children. Furthermore, the odds ratio indicated that mothers who used no methods for alleviating stress were twice as likely to have depressive symptoms than those who did. 相似文献
Summary Platelet-rich plasma (PRP) has been used to promote periodontal regeneration following the premise that constituent transforming
growth factor-β1 (TGF-β1) and platelet-derived growth factor-AB will stimulate cell proliferation at the site of application.
In previous studies, we demonstrated that PRP mimics TGF-β1 to modulate proliferation in a cell type-specific manner, that
fibrin clot formation by PRP upregulates type I collagen, and that an unidentified factor(s) in PRP increases alkaline phosphatase
(ALP) activity in human periodontal ligament (PDL) cell cultures. We have now examined the effects of PRP on in vitro mineralization.
Platelet-rich plasma and PDL cells were prepared from human adult volunteers or rats. After 20 d of continuous treatment with
PRP in dexamethazone (Dex)-containing osteogenic medium, PRP time dependently promoted mineralization by rat PDL cells but
failed to fully induce the osteoblastic phenotype. Furthermore, when human PDL cells were induced to increase ALP activity
in osteogenic medium that lacked Dex, a condition that should delay (or suppress) osteoblastic differentiation, transmission
electron microscopy revealed that mineralized spicules were initially deposited onto PRP-derived platelet aggregates. Taken
together with our previous data, these findings suggest that PRP provides platelet aggregates as nuclei to initiate mineralization
while stimulating PDL cell proliferation, differentiation, and collagen production. The combination of these effects may effectively
mediate PRP's ability to promote regeneration of periodontal tissue, including skeletal tissue, at the site of injury. 相似文献
Expression of somatostatin in the brain declines during aging in various mammals including apes and humans. A prominent decrease in this neuropeptide also represents a pathological characteristic of Alzheimer disease. Using in vitro and in vivo paradigms, we show that somatostatin regulates the metabolism of amyloid beta peptide (Abeta), the primary pathogenic agent of Alzheimer disease, in the brain through modulating proteolytic degradation catalyzed by neprilysin. Among various effector candidates, only somatostatin upregulated neprilysin activity in primary cortical neurons. A genetic deficiency of somatostatin altered hippocampal neprilysin activity and localization, and increased the quantity of a hydrophobic 42-mer form of Abeta, Abeta(42), in a manner similar to presenilin gene mutations that cause familial Alzheimer disease. These results indicate that the aging-induced downregulation of somatostatin expression may be a trigger for Abeta accumulation leading to late-onset sporadic Alzheimer disease, and suggest that somatostatin receptors may be pharmacological-target candidates for prevention and treatment of Alzheimer disease. 相似文献