Action Potentials ; Animals ; Calcium Channels, L-Type ; genetics ; Dogs ; Heart Atria ; metabolism ; Kv Channel-Interacting Proteins ; genetics ; RNA, Messenger ; analysis ; Shal Potassium Channels ; genetics

Human K(v) channel interacting protein 1 (KCHIP1) is a new member of the neural calcium binding protein superfamily. Theoretically KCHIP1 has several calcium binding domains and two myristoylation sites. In this study, we demonstrated that the calcium binding domains and myristoylation sites were functional. The first, through running SDS-PAGE gel, we testified its ability of binding Ca(2+) with obvious discrepancy of the electrophoresis migrating rate after binding Ca(2+). Then, through the techniques of fused green fluorescence protein and site-directed mutagenesis, we demonstrated that wild type KCHIP1 protein accumulated in the secretory vesicles of Golgi body. In contrast, its two mutated forms without myristoylation sites accumulated throughout the whole cytoplasm. These observations indicate that KCHIP1 protein has a myristoylation motif mediating the interaction between KCHIP1 protein and membrane.
Animals ; COS Cells ; Calcium ; metabolism ; Calcium-Binding Proteins ; genetics ; metabolism ; Cercopithecus aethiops ; Humans ; Kv Channel-Interacting Proteins ; chemistry ; physiology ; Potassium Channels ; metabolism ; Potassium Channels, Voltage-Gated ; metabolism ; Protein Transport ; Recombinant Fusion Proteins ; metabolism ; Transfection

OBJECTIVETo understand the role of KCNE2 in functional regulation of Kv4.3, the major alpha subunit of transient outward current (I(to)) in human heart.

METHODSThe cDNAs of Kv4.3 or Kv4.3 plus KCNE2 were transfected into COS-7 cells and 24-36 h after the transfection, the channel proteins were expressed in the surface membrane of the cells and the channel currents were recorded with patch-clamp technique in whole-cell mode.

RESULTSKCNE2 played an important role in modulating the channel function. The recorded current density was decreased in cells co-expressing KCNE2 and Kv4.3 to 152.96-/+33.71 pA/pF (n=16) as compared with Kv4.3-expressing cells with a mean current density of 375.13-/+112.87 pA/pF (n=11). At the recording voltage of 60 mV, KCNE2 increased the time to peak (TTP) of the current. TTP in only Kv4.3-expressing cells was 4.82-/+0.32 ms (n=11), significantly shorter than the TTP of 20.41-/+2.13 ms (n=16) in cells co-expressing Kv4.3 and KCNE2 (P<0.05). In the presence of KCNE2, the voltage-dependent inactivation of Kv4.3 showed a positive shift. The voltage of half maximum inactivation (V(0.5)) was decreased significantly from -53.62-/+1.24 mV (n=8) in Kv4.3 group to -46.58-/+1.6 mV (n=10) in KCNE2 co-expression group (P<0.05). KCNE2 accelerated the recovery of the channel from inactivation, reducing the recovery time constant (tau) from 193.43-/+17.98 ms to 137.71-/+18.29 ms.

CONCLUSIONKCNE2 might serve as an important beta subunit and play a role in the regulation of I(to) function in human heart.

Animals ; COS Cells ; Cercopithecus aethiops ; Humans ; Kv Channel-Interacting Proteins ; genetics ; metabolism ; Membrane Potentials ; physiology ; Patch-Clamp Techniques ; Potassium Channels, Voltage-Gated ; genetics ; metabolism ; physiology ; Shal Potassium Channels ; genetics ; metabolism ; physiology ; Transfection

OBJECTIVETo detect the KChIP2 mRNA level in rheumatic heart disease patients with or without atrial fibrillation (AF) by real-time PCR.

METHODSRight atrial appendage samples from rheumatic heart disease patients with (n = 17) or without AF (n = 13) were obtained during cardiac surgery. Total RNA was extracted from the atrial tissues, and the KChIP2 and Kv4.3 mRNA were detected by SYBR Green I real-time PCR with the GAPDH as the house keeping gene.

RESULTThe ratio of KChIP2/GAPDH (0.1468 +/- 0.0452 vs. 0.2200 +/- 0.0388, P<0.01) and the ratio of Kv4.3/GAPDH (0.3946 +/- 0.1826 vs. 0.5257 +/- 0.1427, P<0.05) were significantly lower in AF patients compared to non-AF patients.

CONCLUSIONDown-regulated atrial KChIP2 and Kv4.3 mRNA expressions in rheumatic heart disease patients with chronic AF might be one of the molecular bases responsible for the down-regulation of the I(to) current density of AF.

Adult ; Atrial Fibrillation ; genetics ; Down-Regulation ; Female ; Humans ; Kv Channel-Interacting Proteins ; genetics ; Male ; Middle Aged ; Myocytes, Cardiac ; metabolism ; RNA, Messenger ; genetics ; Rheumatic Heart Disease ; genetics ; Shal Potassium Channels ; genetics

OBJECTIVE: To construct the recombinant lentivirus vector containing short hairpin RNA (shRNA) inhibited DREAM expression and to investigate the gene therapy of neuropathic pain by inhibiting the expression of DREAM gene by RNA interference. METHODS: An effective short hairpin RNA targeting to rat DREAM was cloned into the plasmids on the base of Lentivirous vectors, pKCSHR-Puro/GFP, and both of the pKCSHR-Puro/GFP-DREAM and Lentivector package plasmids mix were transferred into the 293T cells. The culture supernatant was harvested, and the virus titer was detected 48 hours after transferring. Thirty-six sheer breed pathogen free adult Sprague Dawley rats were randomly divided into 6 groups (6 in each group): normal control group (N); sham-operated group (S); CCI group (C0 group):CCI model without any intervention; Saline control group (C1 group); empty vector control group (C2 group); and LV-shRNADREAM lentiviral vector treatment group (C3 group). The rats in the last 3 groups respectively accepted injection of normal saline, blank vector, LV-shRNADREAM lentiviral vector in the subarachnoid on the 7th day after CCI, and the pain behavior was observed after 3, 7, 10, 14, 21 d after CCI. Green fluorescent protein (GFP) expression was detected by fluorescence microscope and the contents of DREAM mRNA and DREAM protein were detected by Realtime PCR and Western blot respectively in the rat lumbar spinal cord. RESULTS: The short hairpin RNA sequences targeting at rat DREAM were cloned into the vectors, and an entry clone and an expression clone were constructed successfully confirmed by sequence analysis. Lentiviral packaging was successful in 293 T cell line and the transfection titer of the lentivirus was 1 x 10(8) IFU/mL. LV-shRNADREAM lentivirus vector was transfected successfully in the rat spine with Intrathecal injection of LV-shRNADREAM. Compared with the other 3 groups, heat pain threshold and mechanical pain threshold in Group C3 improved significantly (P<0.01), and the expression of DREAM mRNA and DREAM protein in the lumbar spinal cord in Group C3 were lowered significantly (P<0.01). CONCLUSION Lentivirus vectors containing rat DREAM gene are constructed successfully, and lentivirus mediated shRNA can inhibit the DREAM expression in the rat spine, which may prove to be an effective method for neuropathic pain.
Analgesia ; methods ; Animals ; Base Sequence ; Genetic Therapy ; methods ; Genetic Vectors ; genetics ; Kv Channel-Interacting Proteins ; biosynthesis ; genetics ; Lentivirus ; genetics ; metabolism ; Male ; Molecular Sequence Data ; Pain ; etiology ; Pain Management ; RNA Interference ; RNA, Small Interfering ; genetics ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Repressor Proteins ; biosynthesis ; genetics ; Sciatic Nerve ; injuries ; Transfection