LncRNA XIST facilitates the odontogenic differentiation of dental pulp stem cells via the FUS/ZBTB16

Abstract Objective This study aims to explore the regulatory mechanism of long noncoding RNA X inactive specific transcript (lncRNA XIST) in the odontogenic differentiation of human dental pulp stem cells (hDPSCs). hDPSCs were obtained from freshly extracted third molars and identified by flow cytometry. Methodology Odontogenic differentiation was induced in mineralized culture medium, and hDPSCs were infected with shRNA lentivirus targeting XIST or fused in sarcoma (FUS), followed by detection of alkaline phoshpatase (ALP) activity, alizarin red staining of mineralized nodules, Real-Time Quantitative Reverse Transcription PCR (qRT-PCR) quantification of XIST expression, and Western blot analysis of FUS, ZBTB16, and odontogenic differentiation markers (DSPP and DMP1). IF-FISH was performed to detect the cellular localization of XIST and FUS. RIP assay validated the XIST and FUS binding. ZBTB16 mRNA stability was tested after actinomycin D treatment. hDPSCs were infected with oe-ZBTB16 lentivirus and further treated with sh-XIST for a combined experiment. Results LncRNA XIST was highly expressed in hDPSCs with odontogenic differentiation. Downregulation of XIST or FUS weakened the ALP activity of hDPSCs, reduced mineralized nodules, diminished DSPP and DMP1 expressions. XIST binds to FUS to stabilize ZBTB16 mRNA and promote ZBTB16 expression. ZBTB16 overexpression partially reversed the inhibitory effect of XIST silencing on odontogenic differentiation of hDPSCs. Conclusion In conclusion, XIST stabilizes ZBTB16 mRNA and promotes ZBTB16 expression by binding to FUS, thereby facilitating the odontogenic differentiation of hDPSCs.

ZBTB16-RARalpha variant of acute promyelocytic leukemia with tuberculosis: a case report and review of literature

A 23-year-old male presented with pulmonary tuberculosis and swelling of both lower limbs. He was put on antitubercular treatment. Hemogram showed mild anemia and Pseudo Pelger-huet cells. The bone marrow (BM) examination showed 52% promyelocytes with regular round to oval nuclei, few granules and were positive for CD13 and CD33, and negative for HLA-DR. Cytogenetic analysis of the BM aspirate revealed an apparently balanced t(11;17)(q23;q21). Final diagnosis rendered was acute promyelocytic leukemia (APL) with t(11;17)(q23;q21); ZBTB16/RARA. APL is a distinct subtype of acute myeloid leukemia. The variant APL with t(11;17)(q23;q21) cases that are associated with the ZBTB16/RARA fusion gene have been reported as being resistant to all-trans-retinoic acid (ATRA). Therefore, differential diagnosis of variant APL with t(11;17)(q23;q12) from classical APL with t(15;17)(q22;q12); PML-RARA is very important. Here we have discussed the importance of distinct morphology of variant APL and also significance of rare presentation with tuberculosis.

A variant acute promyelocytic leukemia with t(11;17) (q23;q12); ZBTB16-RARA showing typical morphology of classical acute promyelocytic leukemia

A subgroup of acute leukemia with morphology resembling acute promyelocytic leukemia (APL) shows variant translocations involving RARA and has a different morphology from that of classical APL. The variant APL with t(11;17)(q23;q12); ZBTB16-RARA subgroup has been reported to have leukemic cells with regular nuclei, many granules, absence of Auer rods, an increased number of Pelgeroid neutrophils, strong myeloperoxidase (MPO) activity, and all-trans-retinoic-acid (ATRA) resistance. Here, we report a case of variant APL with t(11;17)(q23;q12); ZBTB16-RARA showing typical morphological features of classical APL, including numerous Auer rods and faggot cells. The leukemic cells expressed CD13, CD33, CD117, human leukocyte antigen (HLA)-DR, and cytoplasmic-MPO on the immunophenotyping study. The diagnosis was confirmed by cytogenetic and molecular studies. To distinguish variant APL cases from classical APL cases, regardless of whether morphologically the findings are consistent with those of classical APL, combining morphologic, immunophenotypic, cytogenetic, and molecular studies before chemotherapy is very important.