Roles of functional lipids in bacteriorhodopsin photocycle in various delipidated purple membranes.

Purple membrane (PM) is composed of several native lipids and the transmembrane protein bacteriorhodopsin (bR) in trimeric configuration. The delipidated PM (dPM) samples can be prepared by treating PM with CHAPS (3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate) to partially remove native lipids while maintaining bR in the trimeric configuration. By correlating the photocycle kinetics of bR and the exact lipid compositions of the various dPM samples, one can reveal the roles of native PM lipids. However, it is challenging to compare the lipid compositions of the various dPM samples quantitatively. Here, we utilize the absorbances of extracted retinal at 382 nm to normalize the concentrations of the remaining lipids in each dPM sample, which were then quantified by mass spectrometry, allowing us to compare the lipid compositions of different samples in a quantitative manner. The corresponding photocycle kinetics of bR were probed by transient difference absorption spectroscopy. We found that the removal rate of the polar lipids follows the order of BPG ≈ GlyC < S-TGD-1 ≈ PG < PGP-Me ≈ PGS. Since BPG and GlyC have more nonpolar phytanyl groups than other lipids at the hydrophobic tail, causing a higher affinity with the hydrophobic surface of bR, the corresponding removal rates are slowest. In addition, as the reaction period of PM and CHAPS increases, the residual amounts of PGS and PGP-Me significantly decrease, in concomitance with the decelerated rates of the recovery of ground state and the decay of intermediate M, and the reduced transient population of intermediate O. PGS and PGP-Me are the lipids with the highest correlation to the photocycle activity among the six polar lipids of PM. From a practical viewpoint, combining optical spectroscopy and mass spectrometry appears a promising approach to simultaneously track the functions and the concomitant active components in a given biological system.

SPAG6 regulates cell proliferation and apoptosis via TGF-ß/Smad signal pathway in adult B-cell acute lymphoblastic leukemia.

Adult B-cell acute lymphoblastic leukemia (B-ALL) prognosis remains unsatisfactory, and searching for new therapeutic targets is crucial for improving patient prognosis. Sperm-associated antigen 6 (SPAG6), a member of the cancer-testis antigen family, plays an important role in tumors, especially hematologic tumors; however, it is unknown whether SPAG6 plays a role in adult B-ALL. In this study, we demonstrated for the first time that SPAG6 expression was up-regulated in the bone marrow of adult B-ALL patients compared to healthy donors, and expression was significantly reduced in patients who achieved complete remission (CR) after treatment. In addition, patients with high SPAG6 expression were older (≥ 35 years; P = 0.015), had elevated white blood cell counts (WBC > 30 × 109/L; P = 0.021), and a low rate of CR (P = 0.036). We explored the SPAG6 effect on cell function by lentiviral transfection of adult B-ALL cell lines BALL-1 and NALM-6, and discovered that knocking down SPAG6 significantly inhibited cell proliferation and promoted apoptosis. We identified that SPAG6 knockdown might regulate cell proliferation and apoptosis via the transforming growth factor-ß (TGF-ß)/Smad signaling pathway.

[Clinical Analysis of Matched Sibling Donor Allogeneic Hematopoietic Stem Cell Transplantation in the Treatment of Young Patients with Multiple Myeloma].

OBJECTIVE: To investigate the efficacy and safety of matched sibling donor allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the treatment of young patients with multiple myeloma (MM). METHODS: The clinical data of 8 young patients (median age：46 years) with MM who underwent allo-HSCT from HLA-indentical sibling donors in the First Affiliated Hospital of Chongqing Medical University from June 2013 to September 2021 were collected, and their survival and prognosis were retrospectively analyzed. RESULTS: All the patients were successfully transplanted, and 7 patients could be evaluated the efficacy after transplantation. The median follow-up time was 35.2 (2.5-84.70) months. The complete response (CR) rate was 2/8 before transplantation and 6/7 after transplantation. Acute GVHD developed in 2 cases and extensive chronic GVHD developed in 1 case. Within 100 days, 1 case died of non-recurrent events, and 1-year and 2-year disease-free survival were 6 and 5 cases, respectively. At the end of follow-up, all the 5 patients who survived for more than 2 years survived, and the longest disease-free survival time has reached 84 months. CONCLUSION: With the development of new drugs, HLA-matched sibling donor allo-HSCT may be a curable treatment for young patients with MM.