Psychiatry related information on TRPC7

• BACKGROUND: As altered storage-operated calcium (Ca(2+)) entry (SOCE) may affect Ca(2+) homeostasis in bipolar disorder (BD), we determined whether changes occur in the expression of TRPC7 and SERCA2s, proteins implicated or known to be involved in SOCE, in B lymphoblast cell lines (BLCLs) from BD-I patients and comparison subjects [1].

High impact information on TRPC7

• In DT40 B lymphocytes, Canonical Transient Receptor Potential 7 (TRPC7) functions as a diacylglycerol-activated non-selective cation channel [2].
• Native TRPC7 channel activation by an inositol trisphosphate receptor-dependent mechanism [2].
• These responses were absent in TRPC7-/- cells but could be restored by transfection with human TRPC7 [3].
• In comparison with untransfected cells depletion of intracellular calcium stores in hTRP7-expressing cells, using either carbachol or thapsigargin, produced a marked increase in the subsequent level of Ca(2+) influx [4].
• For functional analysis, we heterologously expressed hTRP7 cDNA in an human embryonic kidney cell line [4].

Biological context of TRPC7

• Semiquantitative RT-PCR demonstrated significant up-regulation of TrpC1 in TAL and TNL (P < or = 0.01) and TrpC6 (P < or = 0.01) and TrpC7 (P < or = 0.05) in TAL samples [5].
• Altered TRPC7 gene expression in bipolar-I disorder [1].
• CONCLUSIONS: Reduced TRPC7 gene expression may be a trait associated with pathophysiological disturbances of Ca(2+) homeostasis in a subgroup of BD-I patients [1].
• Gene silencing of the Ca2+-permeable transient receptor potential cation channel TRPC7 significantly blunted PGE2-induced triggering of PS exposure and DNA fragmentation [6].
• In conclusion, K562 cells express Ca2+-permeable TRPC7 channels, which are activated by PGE2 and participate in the triggering of apoptosis [6].

Anatomical context of TRPC7

• We knocked out TRPC7 in DT40 B-cells, which expresses both forms of Ca2+ entry [3].
• At the mRNA level hTRP7 was widely expressed in tissues of the central nervous system, as well as some peripheral tissues such as pituitary gland and kidney [4].
• TRPC7 is a receptor-operated DAG-activated channel in human keratinocytes [7].
• In summary, these findings indicate that a major GnRH molecule in hake pituitary gland is Trp7, Leu8-GnRH, while tilapia brain contains both Trp7, Leu8-GnRH and Gln8-GnRH [8].
• (D-Pro4 D- Trp7 ,9,10)SP4-11 (SPA) has been shown to be a competitive antagonist of the histamine releasing action of substance P in rat peritoneal mast cells [9].

Associations of TRPC7 with chemical compounds

• However, when stably expressed in HEK-293 cells, TRPC7 can be activated by either Ca(2+) store depletion or PLC activation [10].
• TRPM2 (previously designated TRPC7 or LTRPC2) is a Ca2+-permeable nonselective cation channel that contains a C-terminal enzymatic domain with pyrophosphatase activity, which specifically binds ADP-ribose [11].
• In contrast, treatment with the thrombin-tethered ligand receptor peptide TRP-7 (SFLLRNP) induced IL-6 production, but at lower levels than that induced by native alpha-thrombin [12].
• In amphibians only mammalian GnRH ([Arg8] GnRH) and type II GnRH (chicken GnRH II, [His5, Trp7, Tyr8] GnRH) have been identified [13].
• The immunoreactive peak in the final purification step had a retention time identical to that of Trp7, Leu8-GnRH and an UV absorbance (280 nm) peak appropriate for two tryptophan residues in the peptide, as in Trp7, Leu8-GnRH [8].

Other interactions of TRPC7

• RESULTS: TRPC7 mRNA levels were significantly lower in BLCLs from BD-I patients with high BLCL [Ca(2+)]B compared with those showing normal [Ca(2+)]B (-33%, p =.017) and with BD-II patients (-48%, p =.003), major depressive disorder patients (-47%, p =.049) and healthy subjects (-33%, p =.038) [1].
• TRP-14 was also a pulmonary vasodilator with a t1/2R value of 0.8 +/- 0.09 min at a concentration of 10(-7) M; both TRP-14 and TRP-7 were approximately 3-log less potent than equimolar alpha-thrombin.(ABSTRACT TRUNCATED AT 250 WORDS)[14]

Analytical, diagnostic and therapeutic context of TRPC7

• Evidence from co-immunoprecipitation experiments indicates that a TRPC1-TRPC3-TRPC7 complex, predicted from siRNA results, does exist [15].
• We investigated, by using the patch clamp technique, Ca2+-mediated regulation of heterologously expressed TRPC6 and TRPC7 proteins in HEK293 cells, two closely related homologues of the transient receptor potential (TRP) family and molecular candidates for native receptor-operated Ca2+ entry channels [16].
• The major GnRH molecular form co-eluted with salmon brain GnRH (Trp7, Leu8-GnRH) in four different HPLC systems which were specifically designed to separate the four natural vertebrate GnRHs (mammalian, salmon, chicken I and II) [8].

References