Impaired Function of Bone Marrow Mesenchymal Stem Cells from Immune Thrombocytopenia Patients in Inducing Regulatory Dendritic Cell Differentiation Through the Notch-1/Jagged-1 Signaling Pathway

All-trans retinoic acid in hematologic disorders: not just acute promyelocytic leukemia

All-trans retinoic acid (ATRA) plays a role in tissue development, neural function, reproduction, vision, cell growth and differentiation, tumor immunity, and apoptosis. ATRA can act by inducing autophagic signaling, angiogenesis, cell differentiation, apoptosis, and immune function. In the blood system ATRA was first used with great success in acute promyelocytic leukemia (APL), where ATRA differentiated leukemia cells into mature granulocytes. ATRA can play a role not only in APL, but may also play a role in other hematologic diseases such as immune thrombocytopenia (ITP), myelodysplastic syndromes (MDS), non-APL acute myeloid leukemia (AML), aplastic anemia (AA), multiple myeloma (MM), etc., especially by regulating mesenchymal stem cells and regulatory T cells for the treatment of ITP. ATRA can also increase the expression of CD38 expressed by tumor cells, thus improving the efficacy of daratumumab and CD38-CART. In this review, we focus on the mechanism of action of ATRA, its role in various hematologic diseases, drug combinations, and ongoing clinical trials.

All-trans retinoic acid pretreatment of mesenchymal stem cells enhances the therapeutic effect on acute kidney injury

A promising new therapy option for acute kidney injury (AKI) is mesenchymal stem cells (MSCs). However, there are several limitations to the use of MSCs, such as low rates of survival, limited homing capacity, and unclear differentiation. In search of better therapeutic strategies, we explored all-trans retinoic acid (ATRA) pretreatment of MSCs to observe whether it could improve the therapeutic efficacy of AKI. We established a renal ischemia/reperfusion injury model and treated mice with ATRA-pretreated MSCs via tail vein injection. We found that AKI mice treated with ATRA-MSCs significantly improved renal function compared with DMSO-MSCs treatment. RNA sequencing screened that hyaluronic acid (HA) production from MSCs promoted by ATRA. Further validation by chromatin immunoprecipitation experiments verified that retinoic acid receptor RARα/RXRγ was a potential transcription factor for hyaluronic acid synthase 2. Additionally, an in vitro hypoxia/reoxygenation model was established using human proximal tubular epithelial cells (HK-2). After co-culturing HK-2 cells with ATRA-pretreated MSCs, we observed that HA binds to cluster determinant 44 (CD44) and activates the PI3K/AKT pathway, which enhances the anti-inflammatory, anti-apoptotic, and proliferative repair effects of MSCs in AKI. Inhibition of the HA/CD44 axis effectively reverses the renal repair effect of ATRA-pretreated MSCs. Taken together, our study suggests that ATRA pretreatment promotes HA production by MSCs and activates the PI3K/AKT pathway in renal tubular epithelial cells, thereby enhancing the efficacy of MSCs against AKI.

High dimensional proteomic mapping of bone marrow immune characteristics in immune thrombocytopenia

To investigate the role of co-stimulatory and co-inhibitory molecules on immune tolerance in immune thrombocytopenia (ITP), this study mapped the immune cell heterogeneity in the bone marrow of ITP at the single-cell level using Cytometry by Time of Flight (CyTOF). Thirty-six patients with ITP and nine healthy volunteers were enrolled in the study. As soluble immunomodulatory molecules, more sCD25 and sGalectin-9 were detected in ITP patients. On the cell surface, co-stimulatory molecules like ICOS and HVEM were observed to be upregulated in mainly central memory and effector T cells. In contrast, co-inhibitory molecules such as CTLA-4 were significantly reduced in Th1 and Th17 cell subsets. Taking a platelet count of 30×109 L-1 as the cutoff value, ITP patients with high and low platelet counts showed different T cell immune profiles. Antigen-presenting cells such as monocytes and B cells may regulate the activation of T cells through CTLA-4/CD86 and HVEM/BTLA interactions, respectively, and participate in the pathogenesis of ITP. In conclusion, the proteomic and soluble molecular profiles brought insight into the interaction and modulation of immune cells in the bone marrow of ITP. They may offer novel targets to develop personalized immunotherapies.

Successful salvage of a severe COVID-19 patient previously with lung cancer and radiation pneumonitis by mesenchymal stem cells: a case report and literature review

During the COVID-19 pandemic, elderly patients with underlying condition, such as tumors, had poor prognoses after progressing to severe pneumonia and often had poor response to standard treatment. Mesenchymal stem cells (MSCs) may be a promising treatment for patients with severe pneumonia, but MSCs are rarely used for patients with carcinoma. Here, we reported a 67-year-old female patient with lung adenocarcinoma who underwent osimertinib and radiotherapy and suffered from radiation pneumonitis. Unfortunately, she contracted COVID-19 and that rapidly progressed to severe pneumonia. She responded poorly to frontline treatment and was in danger. Subsequently, she received a salvage treatment with four doses of MSCs, and her symptoms surprisingly improved quickly. After a lung CT scan that presented with a significantly improved infection, she was discharged eventually. Her primary disease was stable after 6 months of follow-up, and no tumor recurrence or progression was observed. MSCs may be an effective treatment for hyperactive inflammation due to their ability related to immunomodulation and tissue repair. Our case suggests a potential value of MSCs for severe pneumonia that is unresponsive to conventional therapy after a COVID-19 infection. However, unless the situation is urgent, it needs to be considered with caution for patients with tumors. The safety in tumor patients still needs to be observed.

Magnesium Ions Promote In Vitro Rat Bone Marrow Stromal Cell Angiogenesis Through Notch Signaling

Bone defects are often caused by trauma or surgery and can lead to delayed healing or even bone nonunion, thereby resulting in impaired function of the damaged site. Magnesium ions and related metallic materials play a crucial role in repairing bone defects, but the mechanism remains unclear. In this study, we induced the angiogenic differentiation of bone marrow stromal cells (BMSCs) with different concentrations of magnesium ions. The mechanism was investigated using γ-secretase inhibitor (DAPT) at different time points (7 and 14 days). Angiogenesis, differentiation, migration, and chemotaxis were detected using the tube formation assay, wound-healing assay, and Transwell assay. Besides, we analyzed mRNA expression and the angiogenesis-related protein levels of genes by RT-qPCR and western blot. We discovered that compared with other concentrations, the 5 mM magnesium ion concentration was more conducive to forming tubes. Additionally, hypoxia-inducible factor 1 alpha (Hif-1α) and endothelial nitric oxide (eNOS) expression both increased (p < 0.05). After 7 and 14 days of induction, 5 mM magnesium ion group tube formation, migration, and chemotaxis were enhanced, and the expression of Notch pathway genes increased. Moreover, expression of the Notch target genes hairy and enhancer of split 1 (Hes1) and Hes5 (hairy and enhancer of split 5), as well as the angiogenesis-related genes Hif-1α and eNOS, were enhanced (p < 0.05). However, these trends did not occur when DAPT was applied. This indicates that 5 mM magnesium ion is the optimal concentration for promoting the angiogenesis and differentiation of BMSCs in vitro. By activating the Notch signaling pathway, magnesium ions up-regulate the downstream genes Hes1 and Hes5 and the angiogenesis-related genes Hif-1α and eNOS, thereby promoting the angiogenesis differentiation of BMSCs. Additionally, magnesium ion-induced differentiation enhances the migration and chemotaxis of BMSCs. Thus, we can conclude that magnesium ions and related metallic materials promote angiogenesis to repair bone defects. This provides the rationale for developing artificial magnesium-containing bone materials through tissue engineering.

All-trans retinoic acid added to treatment of primary immune thrombocytopenia: a systematic review and meta-analysis

All-trans retinoic acid (ATRA) application is a novel treatment approach for primary immune thrombocytopenia (ITP). This study aimed to evaluate the efficacy and safety of ATRA in the treatment of ITP. The databases of PubMed (MEDLINE), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), and China National Knowledge Internet were searched on August 5, 2022, to find randomized controlled trials (RCTs) and observational studies. Five observational studies and four RCTs from China were included, and 760 Chinese patients were analyzed. In the five observational studies, the pooled overall response rate (ORR) and complete response rate (CRR) were 59.5% (95% confidence interval [CI], 52.4-66.4%) and 20.6% (95% CI, 14.3-27.6%), respectively. In the selected four RCTs, the pooled odds ratios for sustained response rate, ORR, and CRR were 3.00 (95% CI, 1.97-4.57; P < 0.01), 3.21 (95% CI, 2.15-4.78; P < 0.01), and 2.12 (95% CI, 1.17-3.86; P = 0.01), respectively. ATRA was associated with a reduction in relapse rate and salvage treatment rate (odds ratio, 0.30; 95% CI, 0.18-0.50; P < 0.01; 0.36; 95% CI, 0.23-0.56; P < 0.01, respectively). The pooled odds ratios for grade 1-2 dry skin, headache (or dizziness), and rash acneiform were 49.99 (95% CI, 16.05-155.67; P < 0.01), 1.75 (95% CI, 0.98-3.12; P = 0.06), and 0.37 (95% CI, 0.10-1.34; P = 0.13), respectively. This study suggests that ATRA may significantly improve the initial and long-term response of patients with ITP.

Therapeutic potential of MSCs and MSC-derived extracellular vesicles in immune thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired autoimmune disease involving a variety of immune cells and factors. Despite being a benign disease, it is still considered incurable due to its complex pathogenesis. Mesenchymal stem cells (MSCs), with low immunogenicity, pluripotent differentiation, and immunomodulatory ability, are widely used in a variety of autoimmune diseases. In recent years, impaired bone marrow mesenchymal stem cells (BMMSCs) were found to play an important role in the pathogenesis of ITP; and the therapeutic role of MSCs in ITP has also been supported by increasing evidence with encouraging efficacy. MSCs hold promise as a new approach to treat or even cure refractory ITP. Extracellular vesicles (EVs), as novel carriers in the "paracrine" mechanism of MSCs, are the focus of MSCs. Encouragingly, several studies suggested that EVs may perform similar functions as MSCs to treat ITP. This review summarized the role of MSCs in the pathophysiology and treatment of ITP.

Mesenchymal stem cell-released oncolytic virus: an innovative strategy for cancer treatment

Oncolytic viruses (OVs) infect, multiply, and finally remove tumor cells selectively, causing no damage to normal cells in the process. Because of their specific features, such as, the ability to induce immunogenic cell death and to contain curative transgenes in their genomes, OVs have attracted attention as candidates to be utilized in cooperation with immunotherapies for cancer treatment. This treatment takes advantage of most tumor cells' inherent tendency to be infected by certain OVs and both innate and adaptive immune responses are elicited by OV infection and oncolysis. OVs can also modulate tumor microenvironment and boost anti-tumor immune responses. Mesenchymal stem cells (MSC) are gathering interest as promising anti-cancer treatments with the ability to address a wide range of cancers. MSCs exhibit tumor-trophic migration characteristics, allowing them to be used as delivery vehicles for successful, targeted treatment of isolated tumors and metastatic malignancies. Preclinical and clinical research were reviewed in this study to discuss using MSC-released OVs as a novel method for the treatment of cancer. Video Abstract.

High-throughput DNA methylation analysis in ITP confirms NOTCH1 hypermethylation through the Th1 and Th2 cell differentiation pathways

BACKGROUND

Immune thrombocytopenia (ITP) is a prevalent autoimmune disease with a complex aetiology where DNA methylation changes are becoming triggers.

METHOD

To investigate novel abnormally methylated genes in the pathogenesis of ITP, we performed a high-throughput methylation analysis on 21 ITP patients and 9 normal control samples. We analysed the extent of key methylated genes and their downstream cytokines through Luminex assay or qRT-PCR. Then, bone marrow mononuclear cells were extracted from ITP patients, and decitabine (demethylation drug) was added to the culture medium of cultured cells. qRT-PCR and ELISA were used to detect whether decitabine could effectively affect target genes and related cytokines.

RESULTS

Through the STRING and Metascape databases, hypermethylated NOTCH1 can be identified and can influence ITP by regulating many downstream cytokines through Th1 and Th2 cell differentiation pathways. Compared with those in the normal control group, the expression levels of NOTCH1 and its downstream Th2 cytokines (IL-4, IL-10, and GATA3) were significantly decreased and those of Th1 cytokines (IFN-γ, IL-12, and TNF-α) were significantly increased in the ITP group. Decitabine exerts its demethylation effect, so the expression of NOTCH1 and its related cytokines in the ITP group treated with 100 nM decitabine were significantly reversed.

CONCLUSIONS

Our results suggest that the pathogenesis of ITP may exert its influence on epigenetics through alteration of DNA methylation at regulatory regions of the target NOTCH1 gene in the Th1 and Th2 cell differentiation pathways. At the same time, decitabine may achieve a therapeutic effect on ITP by demethylation.

All-trans retinoic acid plus low-dose rituximab vs low-dose rituximab in corticosteroid-resistant or relapsed ITP

The study aimed to compare the efficacy and safety of all-trans retinoic acid (ATRA) plus low-dose rituximab (LD-RTX) with LD-RTX monotherapy in corticosteroid-resistant or relapsed immune thrombocytopenia (ITP) patients. Recruited patients were randomized at a ratio of 2:1 into 2 groups: 112 patients received LD-RTX plus ATRA, and 56 patients received LD-RTX monotherapy. Overall response (OR), defined as achieving a platelet count of ≥30 × 109/L confirmed on ≥2 separate occasions (≥7 days apart), at least a doubling of the baseline platelet count without any other ITP-specific treatment, and the absence of bleeding within 1 year after enrollment, was observed in more patients in the LD-RTX plus ATRA group (80%) than in the LD-RTX monotherapy group (59%) (between-group difference, 0.22; 95% CI, 0.07-0.36). Sustained response (SR), defined as maintenance of a platelet count &gt;30 × 109/L, an absence of bleeding, and no requirement for any other ITP-specific treatment for 6 consecutive months after achievement of OR during 1 year following enrollment, was achieved by 68 (61%) patients in the combination group and 23 (41%) patients in the monotherapy group (between-group difference, 0.20; 95% CI, 0.04-0.35). The 2 most common adverse events (AEs) for the combination group were dry skin and headache or dizziness. Our findings demonstrated that ATRA plus LD-RTX significantly increased the overall and sustained response, indicating a promising treatment option for corticosteroid-resistant or relapsed adult ITP. This study is registered at www.clinicaltrials.gov as #NCT03304288.

The Extensive Regulation of MicroRNA in Immune Thrombocytopenia

MicroRNA (miRNA) is a small, single-stranded, non-coding RNA molecule that plays a variety of key roles in different biological processes through post-transcriptional regulation of gene expression. MiRNA has been proved to be a variety of cellular processes involved in development, differentiation, signal transduction, and is an important regulator of immune and autoimmune diseases. Therefore, it may act as potent modulators of the immune system and play an important role in the development of several autoimmune diseases. Immune thrombocytopenia (ITP) is an autoimmune systemic disease characterized by a low platelet count. Several studies suggest that like other autoimmune disorders, miRNAs are deeply involved in the pathogenesis of ITP, interacting with the function of innate and adaptive immune responses. In this review, we discuss emerging knowledge about the function of miRNAs in ITP and describe miRNAs in terms of their role in the immune system and autoimmune response. These findings suggest that miRNA may be a useful therapeutic target for ITP by regulating the immune system. In the future, we need to have a more comprehensive understanding of miRNAs and how they regulate the immune system of patients with ITP.

Abnormalities of bone marrow B cells and plasma cells in primary immune thrombocytopenia

The disrupted B-cell subsets and compromised immunosuppressive function of regulatory B cells are found in the BM of patients with ITP.

The abnormally expressed cytokines and their receptors on B cells contribute to the imbalance of BM B-cell subpopulations in ITP.

Primary immune thrombocytopenia (ITP) is an autoantibody-mediated hemorrhagic disorder in which B cells play an essential role. Previous studies have focused on peripheral blood (PB), but B cells in bone marrow (BM) have not been well characterized. We aimed to explore the profile of B-cell subsets and their cytokine environments in the BM of patients with ITP to further clarify the pathogenesis of the disease. B-cell subpopulations and their cytokine/chemokine receptors were detected by using flow cytometry. Plasma concentrations of cytokines/chemokines were measured by using enzyme-linked immunosorbent assay. Messenger RNA levels of B cell–related transcription factors were determined by using quantitative polymerase chain reaction. Regulatory B cell (Breg) function was assessed by quantifying their inhibitory effects on monocytes and T cells in vitro. Decreased proportions of total B cells, naive B cells, and defective Bregs were observed in patients with ITP compared with healthy controls (HCs), whereas an elevated frequency of long-lived plasma cells was found in BM of autoantibody-positive patients. No statistical difference was observed in plasmablasts or in short-lived plasma cells between patients with ITP and HCs. The immunosuppressive capacity of BM Bregs from patients with ITP was considerably weaker than HCs. An in vivo study using an active ITP murine model revealed that Breg transfusion could significantly alleviate thrombocytopenia. Moreover, overactivation of CXCL13-CXCR5 and BAFF/APRIL systems were found in ITP patient BM. Taken together, B-cell subsets in BM were skewed toward a proinflammatory profile in patients with ITP, suggesting the involvement of dysregulated BM B cells in the development of the disease.

All-trans retinoic acid plus low-dose rituximab vs low-dose rituximab in corticosteroid-resistant or relapsed ITP

The study aimed to compare the efficacy and safety of all-trans retinoic acid (ATRA) plus low-dose rituximab (LD-RTX) with LD-RTX monotherapy in corticosteroid-resistant or relapsed immune thrombocytopenia (ITP) patients. Recruited patients were randomized at a ratio of 2:1 into 2 groups: 112 patients received LD-RTX plus ATRA and 56 patients received LD-RTX monotherapy. Overall response (OR), defined as achieving a platelet count of ≥ 30 × 109/L confirmed on at least two separate occasions (at least 7 days apart), at least a doubling of the baseline platelet count without any other ITP-specific treatment and the absence of bleeding within 1 year after enrollment, was observed in more patients in the LD-RTX plus ATRA group (80%) than in the LD-RTX monotherapy group (59%) (between-group difference, 0.22; 95% CI, 0.07 to 0.36). Sustained response (SR), defined as maintenance of a platelet count > 30 x 109/L, an absence of bleeding, and no requirement for any other ITP-specific treatment for 6 consecutive months after achievement of OR during 1 year following enrollment, was achieved by 68 (61%) patients in the combination group and 23 (41%) patients in the monotherapy group (between-group difference, 0.20; 95% CI, 0.04 to 0.35). The 2 most common AEs for the combination group were dry skin and headache or dizziness. Our findings demonstrated that ATRA plus LD-RTX significantly increased the overall and sustained response, indicating a promising treatment option for corticosteroid-resistant or relapsed adult ITP. This study is registered at www.clinicaltrials.gov as #NCT03304288.

All-trans retinoic acid plus high-dose dexamethasone as first-line treatment for patients with newly diagnosed immune thrombocytopenia: a multicentre, open-label, randomised, controlled, phase 2 trial

BACKGROUND

High-dose dexamethasone is the standard initial treatment for patients with immune thrombocytopenia, but many patients still relapse and require further treatments. All-trans retinoic acid has been shown to exert immunomodulatory effects and promote thrombopoiesis, and so we aimed to assess the activity and safety of all-trans retinoic acid plus high-dose dexamethasone as a first-line treatment for newly diagnosed patients with immune thrombocytopenia.

METHODS

This multicentre, open-label, randomised, controlled, phase 2 trial was done at six different tertiary medical centres in China. Eligible participants were adults (aged >18 years) with treatment-naive, newly diagnosed, primary immune thrombocytopenia who had either a platelet count of less than 30 × 109 platelets per L or a platelet count of less than 50 × 109 platelets per L and clinically significant bleeding. We randomly assigned (1:1) participants to receive either all-trans retinoic acid (10 mg orally twice daily for 12 weeks) plus high-dose dexamethasone (40 mg/day intravenously for 4 consecutive days) or high-dose dexamethasone alone using a central, web-based randomisation system. If patients did not respond by day 14, the 4-day course of dexamethasone was repeated. The primary endpoint was 6-month sustained response, defined as the maintenance of a platelet count of at least 30 × 109 platelets per L and at least 2-times higher than the baseline count and the absence of bleeding, with no need for rescue medication at this time. The primary endpoint was analysed by intention-to-treat and safety was assessed in all participants who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, NCT04217148, and is now completed.

FINDINGS

Between Jan 1, 2020, and June 30, 2020, 132 patients were randomly assigned to either all-trans retinoic acid plus high-dose dexamethasone (n=66) or high-dose dexamethasone alone (n=66). Three patients did not receive their allocated treatment, leaving 129 in the safety analysis set. At 6 months, a significantly higher proportion of participants in the all-trans retinoic acid plus high-dose dexamethasone group (45 [68%] of 66) than in the high-dose dexamethasone monotherapy group (27 [41%] of 66) had a sustained response (OR 3·095, 95% CI 1·516-6·318; p=0·0017). The most common adverse events were dry skin (31 [48%] of 64 patients), headaches (12 [19%]), and insomnia (12 [19%]) in the combination group, and insomnia (ten [15%] of 65 patients) and anxiety or mood disorders (eight [12%]) in the monotherapy group. Both treatments were well tolerated and no grade 4 or worse adverse events occurred. There were no treatment-related deaths.

INTERPRETATION

The combination of all-trans retinoic acid and high-dose dexamethasone was safe and active in newly diagnosed patients with primary immune thrombocytopenia, providing a sustained response. This regimen represents a potential first-line treatment in this setting, but further studies are needed to validate its efficacy and safety.

FUNDING

The Beijing Municipal Science and Technology Commission, the National Natural Science Foundation of China, the Beijing Natural Science Foundation, the National Key Research and Development Program of China, and the Foundation for Innovative Research Groups of the National Natural Science Foundation of China.

The Mechanistic Effects and Clinical Applications of Various Derived Mesenchymal Stem Cells in Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by persistent thrombocytopenia resulting from increased platelet destruction and a loss of autoimmune tolerance. The pathogenesis of ITP is highly complex. Although ITP may be effectively controlled with currently available medications in some patients, a subset of cases remain refractory. The application of mesenchymal stem cells (MSCs) for human hematopoietic stem cell transplantation has increasingly demonstrated that MSCs modulate innate or adaptive immunity, thus resulting in a tolerant microenvironment. Functional defects and immunomodulatory disorders have been observed after the use of bone marrow mesenchymal stem cells (BM-MSCs) from patients with ITP. Here, we summarize the underlying mechanisms and clinical applications of various derived MSCs for ITP treatment, focusing on the main mechanisms underlying the functional defects and immune dysfunction of BM-MSCs from patients with ITP. Functional effects associated with the activation of the p53 pathway include decreased activity of the phosphatidylinositol 3 kinase/Akt pathway and activation of the TNFAIP3/NF-κB/SMAD7 pathway. Immune dysfunction appears to be associated with an impaired ability of BM-MSCs to induce various types of immune cells in ITP. At present, research focusing on MSCs in ITP remains in preliminary stages. The application of autologous or exogenous MSCs in the clinical treatment of ITP has been attempted in only a small case study and must be validated in larger-scale clinical trials.

Donor-Specific Regulatory T Cell-Mediated Immune Tolerance in an Intrahepatic Murine Allogeneic Islet Transplantation Model with Short-Term Anti-CD154 mAb Single Treatment

Anti-CD154 blockade-based regimens remain unequaled in prolonging graft survival in various organ transplantation models. Several studies have focused on transplantation tolerance with the anti-CD154 blockade, but none of these studies has investigated the mechanisms associated with its use as the sole treatment in animal models, delaying our understanding of anti-CD154 blockade-mediated immune tolerance. The purpose of this study was to investigate the mechanism underlying the anti-CD154 monoclonal antibody (mAb) blockade in inducing immune tolerance using an intrahepatic murine allogeneic islet transplantation model. Allogeneic BALB/c AnHsd (BALB/c) islets were infused into the liver of diabetic C57BL/6 (B6) mice via the cecal vein. Anti-CD154 mAb (MR1) was administered on -1, 0, 1, 3, 5, and 7 d posttransplantation at 0.5 mg per mouse. We showed that short-term MR1 monotherapy could prolong the allogeneic islet grafts to more than 250 d in the murine intrahepatic islet transplantation model. The second islet grafts transplanted under the kidney capsule of the recipients were protected from rejection. We also found that rejection of same-donor skin grafts transplanted to the tolerant mice was modestly delayed. Using a DEREG mouse model, FoxP3+ regulatory T (Treg) cells were shown to play important roles in transplantation tolerance. In mixed lymphocyte reactions, Treg cells from the tolerant mice showed more potency in suppressing BALB/c splenocyte-stimulated Teff cell proliferation than those from naïve mice. In this study, we demonstrated for the first time that a short-term anti-CD154 mAb single treatment could induce FoxP3+ Treg cell-mediated immune tolerance in the intrahepatic murine allogeneic islet transplantation model.

Mesenchymal stem cell carriers enhance anti-tumor efficacy of oncolytic virotherapy

Oncolytic viruses (OVs) specifically infect, replicate and eventually destroy tumor cells, with no concomitant toxicity to adjacent normal cells. Furthermore, OVs can regulate tumor microenvironments and stimulate anti-tumor immune responses. Mesenchymal stem cells (MSCs) have inherent tumor tropisms and immunosuppressive functions. MSCs carrying OVs not only protect viruses from clearing by the immune system, but they also deliver the virus to tumor lesions. Equally, cytokines released by MSCs enhance anti-tumor immune responses, suggesting that MSCs carrying OVs may be considered as a promising strategy in enhancing the anti-tumor efficacies of virotherapy. In the present review, preclinical and clinical studies were evaluated and discussed, as well as the effectiveness of MSCs carrying OVs for tumor treatment.

Label-Free Mass Spectrometry-Based Plasma Proteomics Identified LY6D, DSC3, CDSN, SERPINB12, and SLURP1 as Novel Protein Biomarkers For Pulmonary Tuberculosis

Aim:

We aimed to identify new plasma biomarkers for the diagnosis of Pulmonary Tuberculosis (PTB).

Background:

Tuberculosis is an ancient infectious disease that remains one of the major global health problems. Until now, effective, convenient, and affordable methods for diagnosis of PTB were still lacking.

Objective:

This study focused on constructing a label-free LC-MS/MS-based comparative proteomics between six tuberculosis patients and six healthy controls to identify Differentially Expressed Proteins (DEPs) in plasma.

Methods:

To reduce the influences of high-abundant proteins, albumin and globulin were removed from plasma samples using affinity gels. Then DEPs from the plasma samples were identified using a label-free Quadrupole-Orbitrap LC-MS/MS system. The results were analyzed by the protein database search algorithm SEQUEST-HT to identify mass spectra to peptides. The predictive abilities of combinations of host markers were investigated by General Discriminant Analysis (GDA), with Leave-One-Out Cross- Validation (LOOCV).

Results:

A total of 572 proteins were identified and 549 proteins were quantified. The threshold for DEPs was set as adjusted p-value < 0.05 and fold change ≥1.5 or ≤0.6667, 32 DEPs were found. ClusterVis, TBtools, and STRING were used to find new potential biomarkers of PTB. Six proteins, LY6D, DSC3, CDSN, FABP5, SERPINB12, and SLURP1, which performed well in the LOOCV method validation, were termed as potential biomarkers. The percentage of cross-validated grouped cases correctly classified and original grouped cases correctly classified is greater than or equal to 91.7%.

Conclusion:

We successfully identified five candidate biomarkers for immunodiagnosis of PTB in plasma, LY6D, DSC3, CDSN, SERPINB12, and SLURP1. Our work supported this group of proteins as potential biomarkers for PTB, and be worthy of further validation.

Senescent mesenchymal stem/stromal cells and restoring their cellular functions

Mesenchymal stem/stromal cells (MSCs) have various properties that make them promising candidates for stem cell-based therapies in clinical settings. These include self-renewal, multilineage differentiation, and immunoregulation. However, recent studies have confirmed that aging is a vital factor that limits their function and therapeutic properties as standardized clinical products. Understanding the features of senescence and exploration of cell rejuvenation methods are necessary to develop effective strategies that can overcome the shortage and instability of MSCs. This review will summarize the current knowledge on characteristics and functional changes of aged MSCs. Additionally, it will highlight cell rejuvenation strategies such as molecular regulation, non-coding RNA modifications, and microenvironment controls that may enhance the therapeutic potential of MSCs in clinical settings.

Role of bone marrow-derived mesenchymal stem cell defects in CD8+ CD28- suppressor T-lymphocyte induction in patients with immune thrombocytopenia and associated mechanisms

Many immune dysfunctions participate in immune thrombocytopenia (ITP) pathogenesis, including numeric and functional defects in suppressor T (Ts) cells and immune-regulation abnormalities in mesenchymal stem cells (MSCs). Recent studies showed that MSCs can promote Ts cell differentiation. Thus, we compared the Ts cell induction ability of bone marrow-derived MSCs (BM-MSCs) between patients with ITP and normal controls (NCs), and examined the mechanism of this difference. Co-culture of CD8⁺ T cells with BM-MSCs revealed that BM-MSCs elevated Ts cell percentage and function, but the efficiency was lower in patients with ITP than in NCs. Blockade experiments showed that blockade of interleukin 6 (IL-6) partially reversed Ts cell induction by BM-MSCs. Addition of exogenous IL-6 down-regulated Ts cell apoptosis. Moreover, BM-MSCs enhanced IL-10 secretion and inhibition ability of Ts cells. IL-6 secretion, regulatory abilities of IL-10 expression in Ts cells, and the enhanced efficiency of Ts cells inhibition function by BM-MSCs were all decreased in patients with ITP. All-trans retinoic acid preconditioning promoted BM-MSC induction of Ts cell percentages and umbilical cord-derived (UC) MSCs efficiently improved ITP Ts cell numbers and dysfunction. In conclusion, defects of BM-MSCs in Ts cell induction are involved in ITP pathogenesis, and exogenous UC-MSCs may be useful for ITP therapy.

LKB1 Promotes the Transformation of Bone Marrow Mesenchymal Stem Cells into Adipocytes Under Oxidative Stress via AMPK-mTOR Signaling Pathway

Bone marrow mesenchymal stem cells (BM-MSCs) are cells with the potential to differentiate into adipocytes in oxidative stress. In this study, tert-butyl hydroperoxide is used as a stimulator that promotes reactive oxygen species in BM-MSCs. The results demonstrate that knockdown of LKB1 inhibits the transformation of BM-MSCs into adipocytes in the presence of oxidative stress. In addition, β3 adrenergic receptor agonists, a positive stimulatory molecule for the transformation of BM-MSCs into adipocytes, restores the transformation ability of BM-MSCs caused by LKB1-siRNA. As an upstream signal of adenosine monophosphate-activated protein kinase (AMPK), LKB1 activates the AMPK pathway and promotes the expression of PPARγ and CCAAT/enhancer binding proteins (C/EBPα). This indicates that the regulation of LKB1 on BM-MSCs is dependent on the AMPK pathway. Immunofluorescence localization experiments reveal that the LKB1 and AMPK localizations partially overlap, oxidative stress promotes their expression in the cytoplasm. In general, LKB1 promotes the transformation of BM-MSCs to adipocytes by activating AMPK pathway under oxidative stress.

miRNA-98-5p Targeting IGF2BP1 Induces Mesenchymal Stem Cell Apoptosis by Modulating PI3K/Akt and p53 in Immune Thrombocytopenia

Immune thrombocytopenia (ITP) is a common hematological autoimmune disease, in which defective mesenchymal stem cells (MSCs) are potentially involved. Our previous study suggested that MSCs in ITP patients displayed enhanced apoptosis. MicroRNAs (miRNAs) play important roles in ITP by affecting megakaryopoiesis, platelet production and immunoregulation, whereas the roles of miRNAs in ITP-MSCs remain unknown. In a previous study, we performed microarray analysis to obtain mRNA and miRNA profiles of ITP-MSCs. In the present study, we reanalyze the data and identify miR-98-5p as a candidate miRNA contributing to MSC deficiency in ITP. miR-98-5p acts through targeting insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1), and the subsequent downregulation of insulin-like growth factor 2 (IGF-2) causes inhibition of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which is involved in the process of MSC deficiency. Furthermore, miR-98-5p upregulates p53 by inhibiting β-transducin repeat-containing protein (β-TrCP)-dependent p53 ubiquitination. Moreover, miR-98-5p overexpression impairs the therapeutic effect of MSCs in ITP mice. All-trans retinoic acid (ATRA) protects MSCs from apoptosis by downregulating miR-98-5p, thus providing a potential therapeutic approach for ITP. Our findings demonstrate that miR-98-5p is a critical regulator of ITP-MSCs, which will help us thoroughly understand the pathogenesis of ITP.

Long noncoding RNA SNHG17 induced by YY1 facilitates the glioma progression through targeting miR-506-3p/CTNNB1 axis to activate Wnt/β-catenin signaling pathway

Background

Glioma is one of the most widely diagnosed malignancies worldwide. It has been reported that long noncoding RNAs (lncRNAs) are participators in the tumorgenesis of cancers. Nevertheless, the role and function of lncRNA SNHG17 among glioma is unclear.

Methods

RT-qPCR revealed SNHG17, YY1, miR-506-3p, CTNNB1 expression among glioma cells. CCK-8, colony formation, EdU, flow cytometry, TUNEL and western blot assays revealed the function of SNHG17 in glioma. RIP uncovered SNHG17, miR-506-3p and CTNNB1 enrichment in RISC complex. Luciferase reporter assays and RNA pull down revealed interaction of miR-506-3p with SNHG17 and CTNNB1.

Results

SNHG17 expression was up-regulated in glioma tissues and cells. SNHG17 silence attenuated cell proliferation and promoted apoptosis and repressed tumor growth. Moreover, SNHG17 was up-regulated by transcription factor YY1. Mechanistically, SNHG17 activated Wnt/β-catenin signaling pathway in glioma. CTNNB1 was referred to as the mRNA of β-catenin, we validated that SNHG17 bound to miR-506-3p to induce CTNNB1 and activate Wnt/β-catenin signaling pathway. Rescue experiments indicated that CTNNB1 overexpression abolished the inhibitory effects of SNHG7 inhibition on glioma progression.

Conclusions

The findings that YY1-induced SNHG17 facilitated the glioma progression through targeting miR-506-3p/CTNNB1 axis to activate Wnt/β-catenin signaling pathway offered a brand-new prospects to molecular-targeted treatment for glioma.

A new NOTCH3 damaging variant in a thrombocytopenia family of Miao ethnic group

BACKGROUND

Pediatric inherited thrombocytopenia, also known as a deficiency of platelets in children, is caused by genetic factors and it is hard to obtain an effective treatment. Thus, it is necessary to identify the possible genetic variants that are responsible for thrombocytopenia.

METHODS

Whole exome sequencing was used to detect genetic variants in two members of a thrombocytopenia family of Miao ethnic group. Multiple in silico analyses were performed to evaluate the effects of the novel missense variants.

RESULTS

Finally, a novel variant (chr19: g.15170364G>A) in the NOTCH3 gene was found, as confirmed with Sanger sequencing, which could result in a R1694Q substitution in the protein. This variant was consistently suggested to be damaging by sift (Sorting Tolerant From Intolerant; http://sift.jcvi.org), polyphen (Polymorphism Phenotyping, version 2.0; http://genetics.bwh.harvard.edu/pph2) and mutationtaster (http://www.mutationtaster.org) software. By building the 3D model of the key region of NOTCH3 protein and performing the structure simulation, we found that (i) this variant affected the 3D structure model with a root-mean-square deviation = 0.46 between wild-type and mutant type; (ii) this variant caused the protein to reduce the solvent accessible surface area by 421 Å² ; and (iii) compared to the wild-type protein, the mutant protein had two less amino acids to maintain protein stability.

CONCLUSIONS

A novel damaging variant in the NOTCH3 gene was identified in a thrombocytopenia family with respect to decreasing the stability of NOTCH3, which may help with the prognosis and therapy of inherited thrombocytopenia.

Contextual Regulation of Skeletal Physiology by Notch Signaling

PURPOSE OF REVIEW

This article reviews the past 2 years of research on Notch signaling as it relates to bone physiology, with the goal of reconciling seemingly discrepant findings and identifying fruitful areas of potential future research.

RECENT FINDINGS

Conditional animal models and high-throughput omics have contributed to a greater understanding of the context-dependent role of Notch signaling in bone. However, significant gaps remain in our understanding of how spatiotemporal context and epigenetic state dictate downstream Notch phenotypes. Biphasic activation of Notch signaling orchestrates progression of mesenchymal progenitor cells through the osteoblast lineage, but there is a limited understanding of ligand- and receptor-specific functions. Paracrine Notch signaling through non-osteoblastic cell types contributes additional layers of complexity, and we anticipate impactful future work related to the integration of these cell types and signaling mechanisms.

All-trans retinoic acid protects mesenchymal stem cells from immune thrombocytopenia by regulating the complement-interleukin-1β loop

Enhanced peripheral complement activation has long been considered as one of the major pathogenic elements of immune thrombocytopenia. A dysfunctional bone marrow microenvironment, especially with regards to mesenchymal stem cells, has been observed in patients with immune thrombocytopenia. However, the potential role of the complement system in the dysfunctional bone marrow microenvironment remains poorly understood. In this study, bone marrow samples from patients with immune thrombocytopenia were divided into two groups based on whether or not complement components were deposited on the surfaces of their mesenchymal stem cells. The mesenchymal cells from the group with complement deposition were less numerous, dysfunctional, had a reduced capacity to proliferate, and showed increased apoptosis as well as abnormal secretion of interleukin-1β and C-X-C motif chemokine ligand 12. In vitro treatment with all-trans retinoic acid increased the number and improved the function of the complement-positive bone marrow mesenchymal stem cells by upregulating DNA hypermethylation of the interleukin-1β promoter. In vivo studies showed that all-trans retinoic acid could rescue the impaired mesenchymal stem cells to support the thrombopoietic niche in both patients with immune thrombocytopenia and a murine model of this disease. Taken together, these results indicate that impairment of mesenchymal stem cells, mediated by the complement-interleukin-1β loop, plays a role in the pathogenesis of immune thrombocytopenia. All-trans retinoic acid represents a promising therapeutic approach in patients with immune thrombocytopenia through its effect of repairing mesenchymal stem cell impairment.

Transcriptome analysis of fowl adenovirus serotype 4 infection in chickens

Fowl adenovirus serotype 4 (FAdV-4) is a causative agent of inclusion body hepatitis and hydropericardium–hepatitis syndrome. These diseases cause considerable economic losses in the global poultry industry and are significant stressors for infected chickens. However, the molecular mechanisms of FAdV-4 pathogenesis are poorly understood. In the present study, we identified differentially expressed genes from the livers of FAdV-4-infected chickens using RNA-seq at 7, 14 and 21 days after FAdV-4 infection. We identified 2395 differentially expressed genes at the three time points. These genes were enriched in variety of biological processes and pathways including PPAR and Notch signaling, cytokine–cytokine receptor interactions and Toll-like receptor signaling pathways. The transcriptional data were validated by quantitative real-time PCR. Our results will assist in the understanding of the molecular pathogenesis of FAdV-4 infection and for developing novel antiviral therapies.

Bronchial Epithelial Cells Promote the Differentiation of Th2 Lymphocytes in Airway Microenvironment through Jagged/Notch-1 Signaling after RSV Infection

BACKGROUND

The aim of this study was to investigate the role of Notch-1 signaling through Notch-1 ligands on bronchial epithelial cells (BECs) in regulating the development of T helper 2 (Th2) lymphocytes after RSV infection.

METHODS

Firstly, we analyzed the expression of cytokines and Notch-1 ligands in BECs by using real-time PCR. Then, RSV-infected BECs were co-cultured with CD4+ T cells in a transwell chamber for 48 h, and differentiation of T cells in the lower chamber was determined using flow cytometry and real-time PCR. JAG1 siRNA was then used to determine the effects of Jagged/Notch-1 signaling on the differentiation of Th2. An RSV-infected mouse model was also used to analyze the secretion of Th differentiation-associated cytokines in serum and lung tissues using ELISA, the histopathological changes using HE staining, and the expression of JAG1 and JAG2 in BECs.

RESULTS

The results showed that RSV promoted the expression of Th2-type cytokines and Jagged-1 and inhibited the expression of Jagged-2 in normal BECs. RSV-infected BECs induced Th2 differentiation. In addition, JAG1 downregulation inhibited the differentiation of Th2 and promoted differentiation of Th1. In the RSV-infected mouse model, the RSV titer, inflammation decreased with time. IL-4 and IL-17 increased on day 28 and 60, while IFNγ increased on day 7 and 28. Moreover, the expression of Jagged-1 increased and that of Jagged-2 decreased in BECs, which was consistent with IL-4 production in lung tissues.

CONCLUSION

Our data showed that BECs had the potential to promote the differentiation of Th2 lymphocytes through Jagged-1/Notch-1 signaling.

Skin tissue engineering: wound healing based on stem-cell-based therapeutic strategies

Normal wound healing is a dynamic and complex multiple phase process involving coordinated interactions between growth factors, cytokines, chemokines, and various cells. Any failure in these phases may lead wounds to become chronic and have abnormal scar formation. Chronic wounds affect patients' quality of life, since they require repetitive treatments and incur considerable medical costs. Thus, much effort has been focused on developing novel therapeutic approaches for wound treatment. Stem-cell-based therapeutic strategies have been proposed to treat these wounds. They have shown considerable potential for improving the rate and quality of wound healing and regenerating the skin. However, there are many challenges for using stem cells in skin regeneration. In this review, we present some sets of the data published on using embryonic stem cells, induced pluripotent stem cells, and adult stem cells in healing wounds. Additionally, we will discuss the different angles whereby these cells can contribute to their unique features and show the current drawbacks.

Vascular progenitor cell senescence in patients with Marfan syndrome

Vascular progenitor cells (VPCs) present in the adventitia of the vessel wall play a critical role in the regulation of vascular repair following injury. This study aimed to assess the function of VPCs isolated from patients with Marfan syndrome (MFS). VPCs were isolated from control and MFS donors and characterized. Compared with control‐VPCs, MFS‐VPCs exhibited cellular senescence as demonstrated by increased cell size, higher SA‐β‐gal activity and elevated levels of p53 and p21. RNA sequencing showed that several cellular process‐related pathways including cell cycle and cellular senescence were significantly enriched in MFP‐VPCs. Notably, the expression level of TGF‐β1 was much higher in MFS‐VPCs than control‐VPCs. Treatment of control‐VPCs with TGF‐β1 significantly enhanced mitochondrial reactive oxidative species (ROS) and induced cellular senescence whereas inhibition of ROS reversed these effects. MFS‐VPCs displayed increased mitochondrial fusion and decreased mitochondrial fission. Treatment of control‐VPCs with TGF‐β1 increased mitochondrial fusion and reduced mitochondrial fission. Nonetheless, treatment of mitofusin2 (Mfn2)‐siRNA inhibited TGF‐β1‐induced mitochondrial fusion and cellular senescence. Furthermore, TGF‐β1‐induced mitochondrial fusion was mediated by the AMPK signalling pathway. Our study shows that TGF‐β1 induces VPC senescence in patients with MFS by mediating mitochondrial dynamics via the AMPK signalling pathway.

Clinical Application of Stem/Stromal Cells in COPD

Chronic obstructive pulmonary disease (COPD) is a progressive life-threatening disease that is significantly increasing in prevalence and is predicted to become the third leading cause of death worldwide by 2030. At present, there are no true curative treatments that can stop the progression of the disease, and new therapeutic strategies are desperately needed. Advances in cell-based therapies provide a platform for the development of new therapeutic approaches in severe lung diseases such as COPD. At present, a lot of focus is on mesenchymal stem (stromal) cell (MSC)-based therapies, mainly due to their immunomodulatory properties. Despite increasing number of preclinical studies demonstrating that systemic MSC administration can prevent or treat experimental COPD and emphysema, clinical studies have not been able to reproduce the preclinical results and to date no efficacy or significantly improved lung function or quality of life has been observed in COPD patients. Importantly, the completed appropriately conducted clinical trials uniformly demonstrate that MSC treatment in COPD patients is well tolerated and no toxicities have been observed. All clinical trials performed so far, have been phase I/II studies, underpowered for the detection of potential efficacy. There are several challenges ahead for this field such as standardized isolation and culture procedures to obtain a cell product with high quality and reproducibility, administration strategies, improvement of methods to measure outcomes, and development of potency assays. Moreover, COPD is a complex pathology with a diverse spectrum of clinical phenotypes, and therefore it is essential to develop methods to select the subpopulation of patients that is most likely to potentially respond to MSC administration. In this chapter, we will discuss the current state of the art of MSC-based cell therapy for COPD and the hurdles that need to be overcome.

Mesenchymal Stem Cell-Based Immunomodulation: Properties and Clinical Application

Mesenchymal stem cells (MSCs) are multipotent stem cells characterized by self-renewal, production of clonal cell populations, and multilineage differentiation. They exist in nearly all tissues and play a significant role in tissue repair and regeneration. Additionally, MSCs possess wide immunoregulatory properties via interaction with immune cells in both innate and adaptive immune systems, leading to immunosuppression of various effector functions. Numerous bioactive molecules secreted by MSCs, particularly cytokines, growth factors, and chemokines, exert autocrine/paracrine effects that modulate the physiological processes of MSCs. These invaluable virtues of MSCs provide new insight into potential treatments for tissue damage and inflammation. In particular, their extensive immunosuppressive properties are being explored for promising therapeutic application in immune disorders. Recently, clinical trials for MSC-mediated therapies have rapidly developed for immune-related diseases following reports from preclinical studies declaring their therapeutic safety and efficacy. Though immunotherapy of MSCs remains controversial, these clinical trials pave the way for their widespread therapeutic application in immune-based diseases. In this review, we will summarize and update the latest research findings and clinical trials on MSC-based immunomodulation.

Mesenchymal stem cells attenuate doxorubicin‑induced cellular senescence through the VEGF/Notch/TGF‑β signaling pathway in H9c2 cardiomyocytes

The clinical use of doxorubicin (Dox) is limited by its cardiotoxicity. The fundamental changes it induces include interstitial myocardial fibrosis and the appearance of senescent cardiomyocytes. Mesenchymal stem cell (MSC)‑based therapies have also been reported to modulate cellular senescence, and have been used effectively to treat age‑related cardiovascular diseases. In the present study, the Transwell system was used to coculture H9c2 cells with MSCs, and their proliferation and viability were assessed. The expression of senescence‑related genes p53 and p16, and telomere length were measured using reverse transcription‑quantitative polymerase chain reaction analysis, and the Jagged‑1/Notch‑1 signaling pathway was detected using western blot analysis. The results revealed that Dox induced the senescence of H9c2 cells, characterized by a low proliferation rate, poor viability, reduced telomere length and impaired telomerase activity, and by marked increases in the expression of p53 and p16. By contrast, when cocultured with MSCs in the presence of Dox, H9c2 cell proliferation and viability increased, whereas the expression levels of p53 and p16 decreased, and telomere length and telomerase activity increased. The mechanism underlying the antisenescence function of MSCs was clarified, which involved the vascular endothelial growth factor (VEGF)/Jagged‑1/Notch‑1/transforming growth factor‑β1 (TGF‑β1) signaling pathway. It was confirmed that inhibiting VEGF, or silencing Jagged‑1 or Notch‑1 with small interfering RNA, or using recombinant TGF‑β1 eliminated the antisenescence effects of MSCs on the Dox‑treated H9c2 cells. The results revealed that MSCs rescued H9c2 cells from Dox‑induced senescence through the release of VEGF, which activated the Jagged‑1/Notch‑1 signaling pathway, leading to the inhibition of TGF‑β1 release. Therefore, treatment with MSCs may have important therapeutic implications on the attenuation of cardiotoxicity in patients with cancer treated with Dox.