Clinical characteristics and outcomes of COVID-19 infection in Chinese patients with hematologic malignancies in the Omicron era.

Patients with hematologic malignancies are often immunodeficient and therefore have a higher risk of severe symptoms from coronavirus disease 2019 (COVID-19). We retrospectively examined a cohort of 289 patients from 16 hospitals in Zhejiang Province who had hematologic malignancies and COVID-19 during a period when the Omicron variant was predominant. Univariate analysis showed that some clinical characteristics, including elder age (P = 0.014), multiple comorbid conditions (P = 0.011), and receipt of active antineoplastic therapy (P = 0.018) were associated with an increased risk of severe COVID-19. Patients with severe/critical COVID-19 had significantly lower levels of lymphocytes and serum albumin, and significantly higher levels of D-dimer, lactate dehydrogenase, C-reactive protein, and interleukin-6 (all P < 0.05). Fifty-four patients (18.7%) had symptoms lasting ≥3 weeks, suggesting that persistent long-term COVID-19 infection is likely present in a significant proportion of patients. Receipt of the inactivated vaccine was unrelated to disease severity (P = 0.143), which indicated that many patients with hematologic malignancies may not have effective humoral immunity to inactivated vaccines.

Mutant NPM1 maintains RASGRP3 protein stability via interaction with MID1 to promote acute myeloid leukemia cell proliferation and autophagy.

Acute myeloid leukemia is a heterogeneous hematologic malignancy with high mortality in the world. NPM1 gene mutations are a frequent occurrence in acute myeloid leukemia, leading to abnormal autophagy, while the mechanism of NPM1 mutation-driven acute myeloid leukemia pathogenesis remains to be fully elucidated. GEO microarrays were used to screen for dysregulated autophagy-related genes in NPM1-mutant acute myeloid leukemia and analysis of RASGRP3 expression and prognosis. Next, we explored the potential molecular mechanisms relationship between RASGRP3 and NPM1 through utilizing immunoprecipitation, Western blot, and cycloheximide assay. Further, CCK8, EdU staining, immunofluorescence, and Western blot were performed to explore the effect of RASGRP3 on cell proliferation and apoptosis in NPM1-mutated acute myeloid leukemia. Finally, Western blot was used to study the mechanism of action of RASGRP3. RASGRP3 expression was upregulated in NPM1-mutated acute myeloid leukemia. Mislocalized NPM1-mA in the cytoplasm could bind to E3 ubiquitin-protein ligase MID1 to block degradation of the RASGRP3 protein. RASGRP3 could also activate the EGFR-STAT3 axis to promote proliferation and autophagy in acute myeloid leukemia. In conclusion, our results identified RASGRP3 as a proto-oncogene in NPM1-mutated acute myeloid leukemia. The RASGRP3-EGFR/STAT3 axis may be a promising therapeutic target for this unique leukemic subtype.

Zanubrutinib plus salvage chemotherapy for relapsed or refractory diffuse large B-cell lymphoma.

Introduction: Relapsed or refractory diffuse large B-cell lymphoma (R/R DLBCL) has poor clinical outcomes when treated with conventional salvage chemotherapy. Monotherapy using zanubrutinib, a selective Bruton's tyrosine kinase (BTK) inhibitor, has achieved modest antitumor effect in R/R DLBCL. Here we aimed to evaluate the efficacy and safety of zanubrutinib plus salvage chemotherapy in R/R DLBCL patients. Methods: We retrospectively reviewed R/R DLBCL patients who were administered with zanubrutinib plus salvage chemotherapy in our center between January, 2019 and December, 2021. Targeted panel sequencing of 11 lymphoma-related genes was performed on 8 patients with poor responses to zanubrutinib-based chemotherapy. Results: 27 R/R DLBCL patients were enrolled. Median age at this study was 59 years (range, 15-72). The best overall response rate (ORR) was 74.1% and complete remission rate was 33.3%. With a median follow-up of 11 months (range, 1-17), the median progression-free survival (PFS) was 8.1 months, and the overall survival (OS) was not achieved. The most common grade-3/4 adverse events were neutropenia (70.4%), thrombocytopenia (66.7%), and febrile neutropenia (33.3%). In multivariate analysis, early treatment and overall response after chemotherapy were independent favorable prognostic factors for PFS. Overall response after chemotherapy was an independent favorable factor for OS. Among the 8 patients with poor response to zanubrutinib-based treatment, the majority of patients had NOTCH2 mutations (n=8, 100%) and TP53 mutations (n=7, 87.5%). However, these patients achieved an ORR of 75% at 3 months after CD19-CAR-T cell therapy (including 4 cases of complete remission and 2 cases of partial remission). With a median follow-up of 9 months from CAR-T cell infusion (range, 1-16 months), the median PFS was 14.5 months, and the median OS was not reached. Conclusion: With high efficacy and manageable tolerability, zanubrutinib plus salvage chemotherapy may be a potential treatment option for R/R DLBCL. CAR-T cell therapy may be a priority strategy for these poor responders to BTKi-based treatment.

Chidamide and sintilimab combination in diffuse large B-cell lymphoma progressing after chimeric antigen receptor T therapy.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is curable with first-line chemoimmunotherapy but patients with relapsed/refractory (R/R) DLBCL still face a poor prognosis. For patients with R/R DLBCL, the complete response rate to traditional next-line therapy is only 7% and the median overall survival is 6.3 mo. Recently, CD19-targeting chimeric antigen receptor T cells (CAR-T) have shown promise in clinical trials. However, approximately 50% of patients treated with CAR-T cells ultimately progress and few salvage therapies are effective. CASE SUMMARY: Here, we report on 7 patients with R/R DLBCL whose disease progressed after CAR-T infusion. They received a PD-1 inhibitor (sintilimab) and a histone deacetylase inhibitor (chidamide). Five of the 7 patients tolerated the treatment without any serious adverse events. Two patients discontinued the treatment due to lung infection and rash. At the 20-mo follow-up, the median overall survival of these 7 patients was 6 mo. Of note, there were 2 complete response rates (CRs) and 2 partial response rates (PRs) during this novel therapy, with an overall response rate (ORR) of 57.1%, and one patient had a durable CR that lasted at least 20 mo. CONCLUSION: In conclusion, chidamide combined with sintilimab may be a choice for DLBCL patients progressing after CD19-targeting CAR-T therapy.

Secondary myeloid neoplasms after CD19 CAR T therapy in patients with refractory/relapsed B-cell lymphoma: Case series and review of literature.

Background: Several chimeric antigen receptor T cells (CAR T) targeting CD19 have induced profound and prolonged remission for refractory/relapsed (R/R) B-cell lymphoma. The risk of secondary malignancies, especially myeloid neoplasms, is of particular concern in the CAR T community, which still remains unclear. Methods: Four patients with R/R B-cell lymphoma after CD19 CAR T therapy diagnosed with secondary myeloid neoplasms (SMN) from 2 hospitals in eastern China were presented, including 3 with myelodysplastic syndrome (MDS) and 1 with acute myeloid leukemia (AML). Using single-cell RNA sequencing (scRNA-seq), we compared the cellular components of bone marrow (BM) samples obtained from one of these MDS patients and a health donor. We also provided a review of recently published literature concerning SMN risk of CAR T therapy. Results: Relevant demographic, clinical, laboratory, therapeutic and outcome data were collected and presented by chart review. In our case series, the male-female ratio was 3.0 and the median age at MDS onset was 61.25 years old (range, 50-78). Median number of previous systemic therapies was 4.5 (range, 4-5), including autologous hematopoietic stem cell transplantation (auto-HSCT) in one patient. BM assessments prior to CAR T therapy confirmed normal hematopoiesis without myeloid neoplasms. Moreover, for 3 patients with SMN in our series, cytogenetic analysis predicted a relatively adverse outcome. In our experience and in the literature, treatment choices for the patients with SMN included allogeneic hematopoietic stem cell transplantation (allo-HSCT), hypomethylating agent (HMA), period filgrastim, transfusions and other supportive care. Finally, treatment responses of lymphoma, together with SMN, directly correlated with the overall survival of this community. Of note, it appeared that pathogenesis of MDS wasn't associated with the CAR T toxicities, since all 4 patients experienced a pretty mild CRS of grade 1-2. Additionally, scRNA-seq analysis described the transcriptional alteration of CD34+ cells, identified 13 T/NK clusters, and also indicated increased cytotoxic T cells in MDS BM. Conclusion: Our study illustrated the onset and progression of SMN after CD19 CAR T therapy in patients with R/R B-cell lymphoma, which provides useful information of this uncommon later event.

Tumor-derived extracellular vesicles inhibit osteogenesis and exacerbate myeloma bone disease.

Background: As a hallmark driver of multiple myeloma (MM), MM bone disease (MBD) is unique in that it is characterized by severely impaired osteoblast activity resulting from blocked osteogenesis in bone marrow-derived mesenchymal stem cells (BM-MSCs). The mechanisms underlying this preferential blockade are incompletely understood. Methods: miRNA expression of MM cell-derived extracellular vesicles (MM-EVs) was detected by RNA sequencing. MM-EVs impaired osteogenesis and exacerbated MBD were in vitro and in vivo validated by histochemical staining, qPCR and micro-CT. We additionally examined the correlation between CD138+ circulating EVs (cirEVs) count and bone lesion in de novo MM patients. Results: Here, by sequencing and bioinformatics analysis, we found that MM-EVs were enriched in various molecules negatively regulating osteogenesis. We experimentally verified that MM-EVs inhibited BM-MSC osteogenesis, induced elevated expression of miR-103a-3p inhibiting osteogenesis in BM-MSCs, and increased cell viability and interleukin-6 secretion in MM cells. In a mouse model, MM-EVs that were injected into the marrow space of the left tibia led to impaired osteogenesis and exacerbated MBD and MM progression. Furthermore, the levels of CD138+ cirEVs in the peripheral blood were positively correlated with the number of MM bone lesions in MM patients. Conclusions: These findings suggest that MM-EVs play a pivotal role in the development of severely impaired osteoblast activity, which represents a novel biomarker for the precise diagnosis of MBD and a compelling rationale for exploring MM-EVs as a therapeutic target.

Microvesicles as Potential Biomarkers for the Identification of Senescence in Human Mesenchymal Stem Cells.

Senescence in human mesenchymal stem cells (MSCs) not only contributes to organism aging and the development of a variety of diseases but also severely impairs their therapeutic properties as a promising cell therapy. Studies searching for efficient biomarkers that represent cellular senescence have attracted much attention; however, no single marker currently provides an accurate cell-free representation of cellular senescence. Here, we studied characteristics of MSC-derived microvesicles (MSC-MVs) that may reflect the senescence in their parental MSCs. We found that senescent late passage (LP) MSCs secreted higher levels of MSC-MVs with smaller size than did early passage (EP) MSCs, and the level of CD105+ MSC-MVs decreased with senescence in the parental MSCs. Also, a substantially weaker ability to promote osteogenesis in MSCs was observed in LP than EP MSC-MVs. Comparative analysis of RNA sequencing showed the same trend of decreasing number of highly-expressed miRNAs with increasing number of passages in both MSCs and MSC-MVs. Most of the highly-expressed genes in LP MSCs and the corresponding MSC-MVs were involved in the regulation of senescence-related diseases, such as Alzheimer's disease. Furthermore, based on the miRNA profiling, transcription factors (TF) and genes regulatory networks of MSC senescence, and the datasets from GEO database, we confirmed that expression of miR-146a-5p in MSC-MVs resembled the senescent state of their parental MSCs. Our findings provide evidence that MSC-MVs are a key factor in the senescence-associated secretory phenotype of MSCs and demonstrate that their integrated characteristics can dynamically reflect the senescence state of MSCs representing a potential biomarker for monitoring MSC senescence.

Selective surface marker and miRNA profiles of CD34+ blast-derived microvesicles in chronic myelogenous leukemia.

The present study aimed at investigating the selective enrichment of surface marker and functional microRNA (miRNA) profiles of cluster of differentiation (CD)34+ blast-derived microvesicles (MVs) from parental cells in chronic myelogenous leukemia (CML), thus providing an experimental basis for MVs to be used to predict characteristics of CD34+ blasts. Magnetic activated cell sorting and continuous differential centrifugation were used to isolate primary CML CD34+ blasts and MVs, in addition to utilizing flow cytometry to identify surface markers of CD34+ blasts and blast-derived MVs. Microarray analysis and the reverse transcription-quantitative polymerase chain reaction were performed to analyze miRNA profiles of CD34+ blasts and MVs. The results of the present study indicated that primary CML CD34+ blasts were able to release MVs, which were selectively enriched with the surface markers CD34 and CD123, and functional miRNAs from parental cells. A total of 15 miRNAs were upregulated in CD34+ blast derived-MVs compared with in CD34+ cells. Distinct Kyoto Encyclopedia of Genes and Genomes pathways and Gene Ontology terms characterized by altered gene expression and potentially associated miRNA were identified. Upregulated miRNAs in MVs were associated with cell development, tumorigenesis and signaling pathways involving ErbB and phosphoinositide 3-kinase/protein kinase B. The present study provides evidence, which increases the understanding of physiological functions of cancer-derived MVs, and aids the understanding of the roles of CD34+ blast-derived MVs in CML-associated processes.

Extracellular Vesicle-functionalized Decalcified Bone Matrix Scaffolds with Enhanced Pro-angiogenic and Pro-bone Regeneration Activities.

Vascularization is crucial for bone regeneration after the transplantation of tissue-engineered bone grafts in the clinical setting. Growing evidence suggests that mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) are potently pro-angiogenic both in vitro and in vivo. In the current study, we fabricated a novel EV-functionalized scaffold with enhanced pro-angiogenic and pro-bone regeneration activities by coating decalcified bone matrix (DBM) with MSC-derived EVs. EVs were harvested from rat bone marrow-derived MSCs and the pro-angiogenic potential of EVs was investigated in vitro. DBM scaffolds were then coated with EVs, and the modification was verified by scanning electron microscopy and confocal microscopy. Next, the pro-angiogenic and pro-bone regeneration activities of EV-modified scaffolds were evaluated in a subcutaneous bone formation model in nude mice. Micro-computed tomography scanning analysis showed that EV-modified scaffolds with seeded cells enhanced bone formation. Enhanced bone formation was confirmed by histological analysis. Immunohistochemical staining for CD31 proved that EV-modified scaffolds promoted vascularization in the grafts, thereby enhancing bone regeneration. This novel scaffold modification method provides a promising way to promote vascularization, which is essential for bone tissue engineering.

Interferon-γ alters the immune-related miRNA expression of microvesicles derived from mesenchymal stem cells.

Increasing studies have demonstrated that interferon gamma (IFN-γ), which serves as a critical inflammatory cytokine, is essential to induce the immunosuppressive effects of mesenchymal stem cells (MSCs). However, the mechanisms underlying the enhanced immunosuppressive effects of IFN-γ-stimulated MSCs (γMSCs) are not fully understood. MSC-derived microvesicles (MSC-MVs) have been viewed as potential pivotal mediators of the immunosuppressive effects of MSCs. Moreover, microRNAs (miRNAs) are important regulators of immunological processes and can be shuttled from cell to cell by MVs. The aim of our study was to analyze the the miRNA expression signature of MVs derived from γMSCs (γMSC-MVs), which may provide better understanding of the immunosuppressive property of their parent cells. Through miRNA microarray and bioinformatics analysis, we found 62 significantly differentially expressed miRNAs (DEMs) in γMSC-MVs compared with MSC-MVs. And the potential target genes and signaling pathways regulated by DEMs were predicted and analyzed. Interestingly, many DEMs and predicted signaling pathways had been demonstrated to be involved in immunoregulation. Furthermore, the network between immunoregulation-related pathways and relevant DEMs was constructed. Collectively, our research on the miRNA repertoires of γMSC-MVs not only provides new perspectives into the mechanisms underlying the enhanced immunosuppressive property of γMSCs, but also paves the way to clinical application of these potent organelles in the future.

Tumor Cell-Derived Microvesicles Induced Not Epithelial-Mesenchymal Transition but Apoptosis in Human Proximal Tubular (HK-2) Cells: Implications for Renal Impairment in Multiple Myeloma.

Renal impairment (RI) is one of the hallmarks of multiple myeloma (MM) and carries a poor prognosis. Microvesicles (MVs) are membrane vesicles and play an important role in disease progression. Here, we investigated the role of MVs derived from MM cells (MM-MVs) in RI of MM. We found that MM-MVs significantly inhibited viability and induced apoptosis, but not epithelial-mesenchymal transition in human kidney-2 (HK-2), a human renal tubular epithelial cell line. The protein levels of cleaved caspase-3, 8, and 9, and E-cadherin, were increased, but vementin levels were decreased in the HK-2 cells treated with MM-MVs. Through a comparative sequencing and analysis of RNA content between the MVs from RPMI8226 MM cells (RPMI8226-MVs) and K562 leukemia cells, RPMI8226-MVs were enriched with more renal-pathogenic miRNAs, in which the selective miRNAs may participate in the up-regulation of the levels of cleaved caspase-3. Furthermore, the levels of CD138+ circulating MVs (cirMVs) in the peripheral blood were positively correlated with the severity of RI in newly-diagnosed MM. Our study supports MM-MVs representing a previously undescribed factor and playing a potential role in the development of RI of MM patients, and sheds light on the potential application of CD138+ cirMV counts in precise diagnosis of RI in MM and exploring MM-MVs as a therapeutic target.

Interferon-γ Alters the Immune-related miRNA Expression of Microvesicles Derived from Mesenchymal Stem Cells / 华中科技大学学报（医学）（英德文版）

Increasing studies have demonstrated that interferon gamma (IFN-γ),which serves as a critical inflammatory cytokine,is essential to induce the immunosuppressive effects of mesenchymal stem cells (MSCs).However,the mechanisms underlying the enhanced immunosuppressive effects of IFN-γ-stimulated MSCs (γMSCs) are not fully understood.MSC-derived rnicrovesicles (MSC-MVs) have been viewed as potential pivotal mediators of the immunosuppressive effects of MSCs.Moreover,microRNAs (miRNAs) are important regulators of immunological processes and can be shuttled from cell to cell by MVs.The aim of our study was to analyze the the miRNA expression signature of MVs derived from γMSCs (γMSC-MVs),which may provide better understanding of the immunosuppressive property of their parent cells.Through miRNA microarray and bioinformatics analysis,we found 62 significantly differentially expressed miRNAs (DEMs) in γMSC-MVs compared with MSC-MVs.And the potential target genes and signaling pathways regulated by DEMs were predicted and analyzed.Interestingly,many DEMs and predicted signaling pathways had been.demonstrated to be involved in immunoregulation.Furthermore,the network between immunoregulation-related pathways and relevant DEMs was constructed.Collectively,our research on the miRNA repertoires of γMSC-MVs not only provides new perspectives into the mechanisms underlying the enhanced immunosuppressive property of γMSCs,but also paves the way to clinical application of these potent organelles in the future.

Development of an angiogenesis-promoting microvesicle-alginate-polycaprolactone composite graft for bone tissue engineering applications.

One of the major challenges of bone tissue engineering applications is to construct a fully vascularized implant that can adapt to hypoxic environments in vivo. The incorporation of proangiogenic factors into scaffolds is a widely accepted method of achieving this goal. Recently, the proangiogenic potential of mesenchymal stem cell-derived microvesicles (MSC-MVs) has been confirmed in several studies. In the present study, we incorporated MSC-MVs into alginate-polycaprolactone (PCL) constructs that had previously been developed for bone tissue engineering applications, with the aim of promoting angiogenesis and bone regeneration. MSC-MVs were first isolated from the supernatant of rat bone marrow-derived MSCs and characterized by scanning electron microscopic, confocal microscopic, and flow cytometric analyses. The proangiogenic potential of MSC-MVs was demonstrated by the stimulation of tube formation of human umbilical vein endothelial cells in vitro. MSC-MVs and osteodifferentiated MSCs were then encapsulated with alginate and seeded onto porous three-dimensional printed PCL scaffolds. When combined with osteodifferentiated MSCs, the MV-alginate-PCL constructs enhanced vessel formation and tissue-engineered bone regeneration in a nude mouse subcutaneous bone formation model, as demonstrated by micro-computed tomographic, histological, and immunohistochemical analyses. This MV-alginate-PCL construct may offer a novel, proangiogenic, and cost-effective option for bone tissue engineering.

Mesenchymal Stem Cell-Derived Microvesicles Support Ex Vivo Expansion of Cord Blood-Derived CD34(+) Cells.

Mesenchymal stem cells (MSCs) are known to support the characteristic properties of hematopoietic stem and progenitor cells (HSPCs) in the bone marrow hematopoietic microenvironment. MSCs are used in coculture systems as a feeder layer for the ex vivo expansion of umbilical cord blood (CB) to increase the relatively low number of HSPCs in CB. Findings increasingly suggest that MSC-derived microvesicles (MSC-MVs) play an important role in the biological functions of their parent cells. We speculate that MSC-MVs may recapitulate the hematopoiesis-supporting effects of their parent cells. In the current study, we found MSC-MVs containing microRNAs that are involved in the regulation of hematopoiesis. We also demonstrated that MSC-MVs could improve the expansion of CB-derived mononuclear cells and CD34(+) cells and generate a greater number of primitive progenitor cells in vitro. Additionally, when MSC-MVs were added to the CB-MSC coculture system, they could improve the hematopoiesis-supporting effects of MSCs. These findings highlight the role of MSC-MVs in the ex vivo expansion of CB, which may offer a promising therapeutic approach in CB transplantation.