lncNBAT1/APOBEC3A is a mediator of HBX-induced chemoresistance in diffuse large B cell lymphoma cells.

Individuals with diffuse large B cell lymphoma (DLBCL) infected with hepatitis B virus (HBV) have worse chemotherapy efficacy and poorer outcomes. It is still unclear whether long noncoding RNAs (lncRNAs) serve as prognostic and therapeutic targets in the chemotherapy resistance of individuals with DLBCL and HBV infection. Here we found that the core component of HBV (HBX) directly upregulated the expression of lncNBAT1, which was closely associated with the chemotherapy outcomes of HBV-infected individuals with DLBCL. Upregulation of lncNBAT1 reduced the sensitivity of DLBCL cells to chemotherapeutic agents (methotrexate [MTX] or cytarabine [Ara-C]) that induced S phase arrest, whereas knockdown of lncNBAT1 significantly relieved the chemoresistance of HBX-expressing DLBCLs. Mechanistically, lncNBAT1 could interact with the signal transducer and activator of transcription 1 (STAT1) to prevent its enrichment at the promoter region of the functional target gene apolipoprotein B mRNA editing enzyme catalytic subunit 3A (APOBEC3A), inhibiting expression of APOBEC3A and inducing resistance to MTX in DLBCL cells. Furthermore, clinical data analysis showed that lncNBAT1 and APOBEC3A expression was closely related to the poor prognosis and short survival of individuals with DLBCL. Our findings suggest a potential prognostic marker and a candidate lncRNA target for treating HBV-infected individuals with DLBCL.

Enhancement of Patchoulol Production in Escherichia coli via Multiple Engineering Strategies.

As a natural sesquiterpene compound with numerous biological activities, patchoulol has extensive applications in the cosmetic industry and potential usage in pharmaceuticals. Although several patchoulol-producing microbial strains have been constructed, the low productivity still hampers large-scale fermentation. Escherichia coli possesses the ease of genetic manipulation and simple nutritional requirements and does not comprise competing pathways for the farnesyl diphosphate (FPP) precursor, showing its potential for patchoulol biosynthesis. Here, combinatorial strategies were applied to produce patchoulol in E. coli. The initial strain was constructed, and it produced 14 mg/L patchoulol after fermentation optimization. Patchoulol synthase (PTS) was engineered by semirational design, resulting in improved substrate binding affinity and a patchoulol titer of 40.3 mg/L; the patchoulol titer reached 66.2 mg/L after fusing of PTS with FPP synthase. To further improve the patchoulol production, the genome of an efficient chassis strain was engineered by deleting the competitive routes for acetate, lactate, ethanol, and succinate synthesis and cumulatively enhancing the expression of efflux transporters, which improved patchoulol production to 338.6 mg/L. When tested in a bioreactor, the patchoulol titer and productivity were further improved to 970.1 mg/L and 199 mg/L/d, respectively, and were among the highest levels reported using mineral salt medium.