Search

Background: Donor-specific HLA antibodies are important risk factors in antibody-mediated rejection and graft loss after renal transplantation and are associated with higher rejection rates and lower graft survival. Most de novo donor specific antibodies (dnDSA) after renal transplantation are directed toward donor HLA-DQ antigens. An HLA-DQ antigen is a heterodimer consisting of an alpha and beta chain. Traditionally, HLA-DQAl typing has not been part of pretransplant evaluation. Therefore, DQ alpha proteins are not usually considered in the interpretation of HLA-DQ antibody reactions. Methods: The renal transplant recipient had a 0% panel reactive antibody pretransplant. Two years after transplantation, he developed symptoms of abdominal distension and bilateral lower extremity edema. Histopathological findings on renal puncture biopsy showed a combination of T-cell-mediated acute rejection type ILA and antibody-mediated rejection with a trend toward chronicity in the transplanted kidney. DSAs were investigated by HLA-I (HLA-AR) and HLA-Il (HLA-DRBI/DQAl/DQB 1) single antigen bead (SAB) assay. HLA typing was performed to explain the antibody reactivity patterns by PCR-SSO and Sequencing-based typing (SBT). HLA-Matchmaker analysis was performed to identify eplets that explain antibody reactivity patterns, Results: HLA-II SAB analysis of the patient's serum at the time of rejection showed positive reactions with all DQB1*03:03-carrying beads with high mean fluorescence intensity (MFI). However, DQB1 *03:03 was not a dnDSA antigen. High-resolution HLA typing revealed that HLA-DQAl *05:01 and DQAl *03:02 were mismatched donor antigens. HLA Matchmaker analysis demonstrated reactivity toward 13OR and 116 V eplet on DQAl and DQB1. Conclusions: Antibodies specific to DQα chains after renal transplantation were highlighted. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the pharmacokinetic profiles of baicalin, wogonoside, baicalein and wogonin after oral administration of pure baicalin, Radix scutellariae and Scutellariae-Paeoniae couple extracts were administered and the pharmacokinetics profiles were compared between normal and ulcerative colitis rats. The plasma concentrations of the four flavonoids were determined by using a simple and rapid high-performance liquid chromatography method. All the rats were divided randomly into two groups (ulcerative colitis and normal groups). Each group contained three subgroups: pure baicalin, Radix scutellariae and Scutellariae-Paeoniae couple extracts subgroup. Each group received oral administration of pure baicalin, Radix Scutellariae and Scutellariae-Paeoniae couple extracts at the same dose of 200 mg/kg baicalin. The results showed that wogonoside, possibily as a methylated product of baicalin, was found in plasma after oral administration of pure baicalin or formulas to rats. Baicalin and wogonoside demonstrated bimodal phenomenon. Baicalin and wogonoside in Scutellariae-Paeoniae couple extract had shown better absorption than which in pure baicalin and Radix Scutellariae extract. Whether oral administration of pure baicalin, Radix Scutellariae or Scutellariae-Paeoniae couple extracts, ulcerative colitis rats showed better absorption than normal rats. For example AUC(0-t) of baicalin were: (41.46 ± 0.62), (59.12 ± 6.42) and (104.87 ± 0.86) (μg/mL).h in UC groups vs (17.77 ± 0.66), (28.04 ± 4.06) and (49.01 ± 4.61) (μg/mL).h in normal groups, respectively. The pharmacokinetics properties of the four flavonoids differed between ulcerative colitis and normal rats, including AUC(0-t) and Cmax (p < 0.05). [ABSTRACT FROM AUTHOR]

Faithful chromosome segregation during mitosis is critical for maintaining genome integrity in cell progeny and relies on accurate and robust kinetochore-microtubule attachments. The NDC80 complex, a tetramer comprising kinetochore protein HEC1 (HEC1), NDC80 kinetochore complex component NUF2 (NUF2), NDC80 kinetochore complex component SPC24 (SPC24), and SPC25, plays a critical role in kinetochore-microtubule attachment. Mounting evidence indicates that phosphorylation of HEC1 is important for regulating the binding of the NDC80 complex to microtubules. However, it remains unclear whether other post-translational modifications, such as acetylation, regulate NDC80-microtubule attachment during mitosis. Here, using pulldown assays with HeLa cell lysates and site-directed mutagenesis, we show that HEC1 is a bona fide substrate of the lysine acetyltransferase Tat-interacting protein, 60 kDa (TIP60) and that TIP60-mediated acetylation of HEC1is essential for accurate chromosome segregation in mitosis. We demonstrate that TIP60 regulates the dynamic interactions between NDC80 and spindle microtubules during mitosis and observed that TIP60 acetylates HEC1 at two evolutionarily conserved residues, Lys-53 and Lys-59. Importantly, this acetylation weakened the phosphorylation of the N-terminal HEC1(1-80) region at Ser-55 and Ser-62, which is governed by Aurora B and regulates NDC80-microtubule dynamics, indicating functional cross-talk between these two post-translation modifications of HEC1. Moreover, the TIP60-mediated acetylation was specifically reversed by sirtuin 1 (SIRT1). Taken together, our results define a conserved signaling hierarchy, involving HEC1, TIP60, Aurora B, and SIRT1, that integrates dynamic HEC1 acetylation and phosphorylation for accurate kinetochore-microtubule attachment in the maintenance of genomic stability during mitosis. [ABSTRACT FROM AUTHOR]