Point-of-care N-terminal pro B-type natriuretic peptide assay to screen apparently healthy cats for cardiac disease in general practice.

BACKGROUND: Point-of-care (POC) N-terminal pro B-type natriuretic peptide (NT-proBNP) ELISA test has been evaluated for screening cats for cardiac disease in the referral veterinary setting but less is known about its use in general practice (GP). OBJECTIVES: To evaluate the diagnostic utility of a POC NT-proBNP ELISA in cats seen in GPs. ANIMALS: Two hundred and seventeen apparently healthy cats from 21 GPs. METHODS: This was a prospective, cross-sectional study. Cardiac auscultation and POC NT-proBNP ELISA were done by veterinarians at their GPs. After enrollment at GPs, cats were sent to a cardiology referral hospital for cardiac auscultation and echocardiographic diagnosis. Results were interpreted based on whether cats had normal or abnormal echocardiographic findings. RESULTS: Point-of-care NT-proBNP ELISA results differentiated cats in the abnormal group from those in the normal group with a sensitivity of 43%, specificity of 96%. In cats with a heart murmur at GPs, POC NT-proBNP ELISA results differentiated cats in the abnormal group from those in the normal group with a sensitivity of 71% and a specificity of 92%. CONCLUSION AND CLINICAL IMPORTANCE: In apparently healthy cats in GPs, positive POC NT-proBNP results are associated with heart disease, warranting an echocardiogram, but negative results do not reliably exclude heart disease. These results suggest POC NT-proBNP is not an effective screening test for apparently healthy cats in GPs, although its performance is improved if it is used only in cats that have a heart murmur.

[Efficacy of internalized RGD-modified echogenic liposomes in diagnosis and treatment in a mouse model of rheumatoid arthritis].

OBJECTIVE: To prepare internalized RGD (iRGD) modified echogenic liposomes containing methotrexate (MTX) and indocyanine green (ICG) (iRGD MTX ICG ELIP) and evaluate its targeting efficiency and inhibitory effect combined with ultrasound on synovial cells. METHODS: iRGD MTX ICG ELIP was prepared by the thin film rehydration and freeze-lyophilization method and its general characteristics and acoustic responsiveness were assessed. The targeting effect of the prepared liposome was observed by assessing its cell uptake in vitro. In a mouse model of rheumatiod arthritis, the targeting effect of the prepared liposome was determined by detecting the fluorescence intensity of the drug in arthrosis. The inhibitory effect of iRGD MTX ICG ELIP combined with ultrasound on synovial MH7A cells in vitro were investigated using CCK8 test. RESULTS: The average diameter and zeta potential of iRGD MTX ICG ELIP was 134.4∓17.61 nm and 10.07∓4.28 mV, and the entrapment efficiency of MTX and ICG was (62.56∓0.77)% and (95.13∓0.82)%, respectively. With ultrasound exposure, the release of MTX and ICG from iRGD MTX ICG ELIP increased with the ultrasound intensity and with the exposure time. In HUVECs, the uptake efficiency of iRGD MTX ICG ELIP was 1.89 times higher than that of non targeted MTX ICG ELIP (P<0.05). In vivo imaging of mouse joint with rheumatiod arthritis showed that the fluorescence intensity of iRGD MTX ICG ELIP was significantly stronger than that of the non targeted liposome. CCK8 assay showed that iRGD MTX ICG ELIP combined with ultrasound resulted in a survival rate of MH7A cells of (32.49∓3.04)%, significantly lower than the rate of cells treated with iRGD MTX ICG ELIP but without ultrasound (P<0.05). CONCLUSIONS: iRGD MTX ICG ELIP has a suitable particle size and can effectively target HUVECs and the joints with rheumatiod arthritis. With a good drug entrapment efficiency and acoustic responsiveness, the drug loaded liposome shows enhanced inhibitory effect on MH7A cells combined with ultrasound in vitro, suggesting its potential in the treatment of rheumatoid arthritis.

Regulation of CLC-1 chloride channel biosynthesis by FKBP8 and Hsp90ß.

Mutations in human CLC-1 chloride channel are associated with the skeletal muscle disorder myotonia congenita. The disease-causing mutant A531V manifests enhanced proteasomal degradation of CLC-1. We recently found that CLC-1 degradation is mediated by cullin 4 ubiquitin ligase complex. It is currently unclear how quality control and protein degradation systems coordinate with each other to process the biosynthesis of CLC-1. Herein we aim to ascertain the molecular nature of the protein quality control system for CLC-1. We identified three CLC-1-interacting proteins that are well-known heat shock protein 90 (Hsp90)-associated co-chaperones: FK506-binding protein 8 (FKBP8), activator of Hsp90 ATPase homolog 1 (Aha1), and Hsp70/Hsp90 organizing protein (HOP). These co-chaperones promote both the protein level and the functional expression of CLC-1 wild-type and A531V mutant. CLC-1 biosynthesis is also facilitated by the molecular chaperones Hsc70 and Hsp90ß. The protein stability of CLC-1 is notably increased by FKBP8 and the Hsp90ß inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) that substantially suppresses cullin 4 expression. We further confirmed that cullin 4 may interact with Hsp90ß and FKBP8. Our data are consistent with the idea that FKBP8 and Hsp90ß play an essential role in the late phase of CLC-1 quality control by dynamically coordinating protein folding and degradation.

The Eag domain regulates the voltage-dependent inactivation of rat Eag1 K+ channels.

Eag (Kv10) and Erg (Kv11) belong to two distinct subfamilies of the ether-à-go-go K+ channel family (KCNH). While Erg channels are characterized by an inward-rectifying current-voltage relationship that results from a C-type inactivation, mammalian Eag channels display little or no voltage-dependent inactivation. Although the amino (N)-terminal region such as the eag domain is not required for the C-type inactivation of Erg channels, an N-terminal deletion in mouse Eag1 has been shown to produce a voltage-dependent inactivation. To further discern the role of the eag domain in the inactivation of Eag1 channels, we generated N-terminal chimeras between rat Eag (rEag1) and human Erg (hERG1) channels that involved swapping the eag domain alone or the complete cytoplasmic N-terminal region. Functional analyses indicated that introduction of the homologous hERG1 eag domain led to both a fast phase and a slow phase of channel inactivation in the rEag1 chimeras. By contrast, the inactivation features were retained in the reverse hERG1 chimeras. Furthermore, an eag domain-lacking rEag1 deletion mutant also showed the fast phase of inactivation that was notably attenuated upon co-expression with the rEag1 eag domain fragment, but not with the hERG1 eag domain fragment. Additionally, we have identified a point mutation in the S4-S5 linker region of rEag1 that resulted in a similar inactivation phenotype. Biophysical analyses of these mutant constructs suggested that the inactivation gating of rEag1 was distinctly different from that of hERG1. Overall, our findings are consistent with the notion that the eag domain plays a critical role in regulating the inactivation gating of rEag1. We propose that the eag domain may destabilize or mask an inherent voltage-dependent inactivation of rEag1 K+ channels.

The subfamily-specific assembly of Eag and Erg K+ channels is determined by both the amino and the carboxyl recognition domains.

A functional voltage-gated K(+) (Kv) channel comprises four pore-forming α-subunits, and only members of the same Kv channel subfamily may co-assemble to form heterotetramers. The ether-à-go-go family of Kv channels (KCNH) encompasses three distinct subfamilies: Eag (Kv10), Erg (Kv11), and Elk (Kv12). Members of different ether-à-go-go subfamilies, such as Eag and Erg, fail to form heterotetramers. Although a short stretch of amino acid sequences in the distal C-terminal section has been implicated in subfamily-specific subunit assembly, it remains unclear whether this region serves as the sole and/or principal subfamily recognition domain for Eag and Erg. Here we aim to ascertain the structural basis underlying the subfamily specificity of ether-à-go-go channels by generating various chimeric constructs between rat Eag1 and human Erg subunits. Biochemical and electrophysiological characterizations of the subunit interaction properties of a series of different chimeric and truncation constructs over the C terminus suggested that the putative C-terminal recognition domain is dispensable for subfamily-specific assembly. Further chimeric analyses over the N terminus revealed that the N-terminal region may also harbor a subfamily recognition domain. Importantly, exchanging either the N-terminal or the C-terminal domain alone led to a virtual loss of the intersubfamily assembly boundary. By contrast, simultaneously swapping both recognition domains resulted in a reversal of subfamily specificity. Our observations are consistent with the notion that both the N-terminal and the C-terminal recognition domains are required to sustain the subfamily-specific assembly of rat Eag1 and human Erg.

A predicted protein, KIAA0247, is a cell cycle modulator in colorectal cancer cells under 5-FU treatment.

BACKGROUND: Colorectal cancer (CRC) is the predominant gastrointestinal malignancy and the leading cause of cancer death. The identification of genes related to CRC is important for the development of successful therapies and earlier diagnosis. METHODS: Molecular analysis of feces was evaluated as a potential method for CRC detection. Expression of a predicted protein with unknown function, KIAA0247, was found in feces evaluated using specific quantitative real-time polymerase chain reaction. Its cellular function was then analyzed using immunofluorescent staining and the changes in the cell cycle in response to 5-fluorouracil (5-FU) were assessed. RESULTS: Gastrointestinal tissues and peripheral blood lymphocytes ubiquitously expressed KIAA0247. 56 CRC patients fell into two group categories according to fecal KIAA0247 mRNA expression levels. The group with higher fecal KIAA0247 (n=22; ≥0.4897) had a significantly greater five-year overall survival rate than the group with lower fecal KIAA0247 (n = 30; <0.4897) (66.0 ± 11.6%; p=0.035, log-rank test). Fecal expression of KIAA0247 inversely related to CRC tumor size (Kendall's tau-b=-0.202; p=0.047). Immunofluorescent staining revealed that the cytoplasm of CRC cells evenly expresses KIAA0247 without 5-FU treatment, and KIAA0247 accumulates in the nucleus after 40 µM 5-FU treatment. In HCT116 p53(-/-) cells, which lack p53 cell cycle control, the proportion of cells in the G2/M phase was larger (13%) in KIAA0247-silent cells than in the respective shLuc control (10%) and KIAA0247-overexpressing cells (7%) after the addition of low dose (40 µM) 5-FU. Expression of three cyclin genes (cyclin A2, cyclin B1, and cyclin B2) also downregulated in the cells overexpressing KIAA0247. CONCLUSIONS: This is the first description of a linkage between KIAA0247 and CRC. The study's data demonstrate overexpression of KIAA0247 associates with 5-FU therapeutic benefits, and also identify the clinical significance of fecal KIAA0247 in CRC.