Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P41181 (collecting duct)
 5,183 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Confluent cultures of two renal collecting duct cell lines (M-1 and mIMCD-K2 cells derived from cortical and inner medullary collecting ducts, respectively) express endothelin1 (ET1), transforming growth factor-beta (TGF beta; both TGF beta 1 and TGF beta 2), and both types of the TGF beta receptor. Experiments were performed to test whether endogenous TGF beta may be a paracrine modulator of ET1 expression in these cells. Treatment of M-1 and mIMCD-K2 cells with TGF beta 2 antisense oligodeoxynucleotides (ODN) significantly reduced ET1 messenger RNA (mRNA) and ET secretion (as well as TGF beta 2 mRNA) in a concentration-dependent manner, whereas control ODN were without significant effects. To produce ET inhibition, antisense ODN had to be present in the basolateral medium, whereas its sole presence in the apical medium was without effect. In addition, a pan-specific TGF beta antibody caused a significant reduction of ET1 mRNA expression and ET1 secretion. M-1 cells were found to express high levels of the mRNA for plasminogen activator of both tissue and urokinase types. Addition of the nonspecific serine protease inhibitor aprotinin (50 micrograms/ml) to the medium for 24 h significantly reduced the secretion of ET1. These results suggest that secretion of endogenous TGF beta, at least in part activated by the plasminogen/plasmin system, participates in the regulation of ET1 synthesis and secretion by collecting duct cell lines.
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PMID:Regulation of endothelin production and secretion in cultured collecting duct cells by endogenous transforming growth factor-beta. 889 74

An apical serine protease, channel-activating protease 1 (CAP1), augments sodium transport in A6 cells. Prostasin, a novel serine protease originally purified from seminal fluid, has been proposed to be the mammalian ortholog of CAP1. We have recently found functional evidence for a similar protease activity in the M-1 cortical collecting duct cell line. The purposes of the present studies were to determine whether prostasin (or CAP1) is present in collecting duct cells by use of mouse M-1 cells, to sequence mouse prostasin, and to further characterize the identity of the serine protease activity and additional functional features in M-1 cells. Using mouse expressed sequence tag sequences that are highly homologous to the published human prostasin sequence as templates, reverse transcription-polymerase chain reaction and RACE (rapid amplification of cDNA ends) were used to sequence mouse prostasin mRNA, which shows 99% identical to published mouse CAP1 sequence. A single 1800-bp transcript was found by Northern analysis, and this was not altered by aldosterone. Equivalent short-circuit current (I(eq)), which represents sodium transport in these cells, dropped to 59+/-3% of control value within 1 hour of incubation with aprotinin, a serine protease inhibitor. Trypsin increased the I(eq) in aprotinin-treated cells to the value of the control group within 5 minutes. Application of aprotinin not only inhibited amiloride sensitive I(eq) but also reduced transepithelial resistance (R(te)) to 43+/-2%, an effect not expected with simple inhibition of sodium channels. Trypsin partially reversed the effect of aprotinin on R(te). Another serine protease inhibitor, soybean trypsin inhibitor (STI), decreased I(eq) in M-1 cells. STI inhibited I(eq) gradually over 6 hours, and the inhibition of I(eq) by 2 inhibitors was additive. STI decreased transepithelial resistance much less than did aprotinin. Neither aldosterone nor dexamethasone significantly augmented protease activity or prostasin mRNA levels, and in fact, dexamethasone decreased prostasin mRNA expression. In conclusion, although prostasin is present in M-1 cells and probably augments sodium transport in these cells, serine proteases probably have other effects (eg, resistance) in the collecting duct in addition to effects on sodium channels. Steroids do not alter these effects in M-1 cells. Additional proteases are likely also present in mouse collecting duct cells.
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PMID:Serine protease activity in m-1 cortical collecting duct cells. 1196 40

A serine protease, prostasin, has been shown to stimulate the activity of amiloride-sensitive sodium channels (ENaC). Prostasin is a glycosylphosphatidylinositol-anchored protein that is found free in physiologic fluids and tissue culture medium, but the mechanism by which prostasin is secreted from the cells has not been elucidated. The current studies found that serine protease inhibitor aprotinin blocked the secretion of prostasin in a mouse cortical collecting duct (CCD) cell line (M-1 cells). A synthetic serine protease inhibitor, nafamostat mesilate (NM), which is commonly used for the treatment of pancreatitis and disseminated intravascular coagulation in Japan, also inhibited the secretion of prostasin in M-1 cells. Continuous infusion of NM into rats resulted in a substantial decrease in urinary prostasin and urinary sodium excretion. p-guanidinobenzoic acid and 6-amidino-2-naphtol, catalytically inactive metabolites of NM, had no effect on prostasin secretion both in M-1 cells and in rats. These findings suggest that a serine protease-sensitive mechanism is involved in the secretion of prostasin in vitro as well as in vivo. Potassium secretion in the CCD is tightly linked to sodium reabsorption through EnaC; therefore, NM-induced decrease in prostasin secretion and subsequent inhibition of ENaC activity could account for the side effects of hyponatremia and/or hyperkalemia that are found sometimes in patients treated with NM. The results indicate an important role for prostasin in sodium reabsorption in the kidney under pathophysiologic conditions.
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PMID:Inhibition of prostasin secretion by serine protease inhibitors in the kidney. 1250 33

Prostasin, a glycosylphosphatidylinositol-anchored serine protease, regulates epithelial sodium channel (ENaC) activity. Sodium reabsorption through ENaC in distal nephron segments is a rate-limiting step in transepithelial sodium transport. Recently, proteolytic cleavage of ENaC subunits by prostasin has been shown to activate ENaC. Therefore, we hypothesized that serine protease inhibitors could inhibit ENaC activity in the kidney, leading to a decrease in blood pressure. We investigated the effects of camostat mesilate, a synthetic serine protease inhibitor, and FOY-251, an active metabolite of camostat mesilate, on sodium transport in the mouse cortical collecting duct cell line (M-1 cells) and on blood pressure in Dahl salt-sensitive rats. Treatment with camostat mesilate or FOY-251 decreased equivalent current (Ieq) in M-1 cells in a dose-dependent manner and inhibited the protease activity of prostasin in vitro. Silencing of the prostasin gene also reduced equivalent current in M-1 cells. The expression level of prostasin protein was not changed by application of camostat mesilate or FOY-251 to M-1 cells. Oral administration of camostat mesilate to Dahl salt-sensitive rats fed a high-salt diet resulted in a significant decrease in blood pressure with elevation of the urinary Na/K ratio, decrease in serum creatinine, reduction in urinary protein excretion, and improvement of renal injury markers such as collagen 1, collagen 3, transforming growth factor-beta1, and nephrin. These findings suggest that camostat mesilate can decrease ENaC activity in M-1 cells probably through the inhibition of prostasin activity, and that camostat mesilate can have beneficial effects on both hypertension and kidney injury in Dahl salt-sensitive rats. Camostat mesilate might represent a new class of antihypertensive drugs with renoprotective effects in patients with salt-sensitive hypertension.
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PMID:Camostat mesilate inhibits prostasin activity and reduces blood pressure and renal injury in salt-sensitive hypertension. 1914 83