Effect of chitin-architected spatiotemporal three-dimensional culture microenvironments on human umbilical cord-derived mesenchymal stem cells

Mesenchymal stem cell (MSC) transplantation has been explored for the clinical treatment of various diseases. However, the current two-dimensional (2D) culture method lacks a natural spatial microenvironment in vitro. This limitation restricts the stable establishment and adaptive maintenance of MSC stemness. Using natural polymers with biocompatibility for constructing stereoscopic MSC microenvironments may have significant application potential. This study used chitin-based nanoscaffolds to establish a novel MSC three-dimensional (3D) culture. We compared 2D and 3D cultured human umbilical cord-derived MSCs (UCMSCs), including differentiation assays, cell markers, proliferation, and angiogenesis. When UCMSCs are in 3D culture, they can differentiate into bone, cartilage, and fat. In 3D culture condition, cell proliferation is enhanced, accompanied by an elevation in the secretion of paracrine factors, including vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), Interleukin-6 (IL-6), and Interleukin-8 (IL-8) by UCMSCs. Additionally, a 3D culture environment promotes angiogenesis and duct formation with HUVECs (Human Umbilical Vein Endothelial Cells), showing greater luminal area, total length, and branching points of tubule formation than a 2D culture. MSCs cultured in a 3D environment exhibit enhanced undifferentiated, as well as higher cell activity, making them a promising candidate for regenerative medicine and therapeutic applications.

HIF-1α induced by hypoxic condition regulates Treg/Th17 axis polarization in chronic immune thrombocytopenia

Immune thrombocytopenia (ITP) is an acquired immune disorder characterized by increased platelet destruction and reduced platelet (Plt) production. Hypoxia-inducible factor-1α (HIF-1α) have regulatory effects on Treg/Th17 axis balance and may represent relevant factors in the pathogenesis of ITP. Treg/Th17 ratio, serum levels and gene expression were investigated in new diagnosed ITP (NITP) and chronic ITP (CITP). The Treg/Th17 ratio obviously decreased in CITP (P = 0.001). The ratio of Treg/Th17 was correlated with the level of HIF-1α level both in mRNA (r = 0.49, P < 0.0001) and serum level (r = 0.50, P < 0.0001). However, none statistical upregulation of HIF-1α was observed in CITP. In vitro, There was significant polarization difference of Treg/Th17 axis (P = 0.042) and Foxp3-MFI/IL17-MFI (P = 0.0003) in hypoxic condition between NITP and CITP. These findings suggest that HIF-1α induced by hypoxia plays a crucial role in the chronicity of ITP by mediating the imbalance of the Treg/Th17 axis.

Identification of metabolism-related key genes as potential biomarkers for pathogenesis of immune thrombocytopenia

Immune thrombocytopenia (ITP), an acquired autoimmune disease, is characterized by immune-mediated platelet destruction. A biomarker is a biological entity that contributes to disease pathogenesis and reflects disease activity. Metabolic alterations are reported to be associated with the occurrence of various diseases. As metabolic biomarkers for ITP have not been identified. This study aimed to identify metabolism-related differentially expressed genes as potential biomarkers for pathogenesis of ITP using bioinformatic analyses.The microarray expression data of the peripheral blood mononuclear cells were downloaded from the Gene Expression Omnibus database (GSE112278 download link: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE112278 ). Key module genes were intersected with metabolism-related genes to obtain the metabolism-related key candidate genes. The hub genes were screened based on the degree function in the coytoscape sofware. The key ITP-related genes were subjected to functional enrichment analysis. Immune infiltration analysis was performed using a single-sample gene set enrichment analysis algorithm to evaluate the differential infiltration levels of immune cell types between ITP patient and control. Molecular subtypes were identified based on the expression of hub genes. The expression of hub genes in the ITP patients was validated using quantitative real-time polymerase chain reaction analysis. This study identified five hub genes (ADH4, CYP7A1, CYP1A2, CYP8B1, and NR1H4), which were be associated with the pathogenesis of ITP, and two molecular subtypes of ITP. Among these hub genes, CYP7A1 and CYP8B1 involved in cholesterol metabolism,were further verified in clinical samples.

Clinical study reveals the efficacy of sirolimus in treating primary immune thrombocytopenia: findings from a single-center study

Immune thrombocytopenia (ITP) is an autoimmune disease that arises because of self-destruction of circulating platelets. The mechanism remains complicated and lacks a standard clinical treatment. Current first-line and second-line medications for ITP have shown limited effectiveness, necessitating the exploration of new therapeutic options. Sirolimus is a mammalian target of rapamycin (mTOR) inhibitor that has been demonstrated to inhibit lymphocyte activity, indicating potential for SRL in the treatment of ITP. This study aimed to evaluate the clinical efficacy of sirolimus as a second-line drug in patients with ITP. The starting dose of sirolimus for adults ranged from 2 to 4 mg/day, with a maintenance dose of 1 to 2 mg/day. For children, the starting dose was 1-2 mg/day, with a maintenance dose of 0.5-1 mg/day. The dosage could be adjusted if needed to maintain a specific blood concentration of sirolimus, typically between 5 and 15 ng/ml, throughout the treatment period. After 3 months, the overall response rate was 60% (12/20), with 30% of patients (6/20) achieving a complete response (CR) and 30% (6/20) achieving a partial response (PR). The CR rate at 6 months remained consistent with the 3-month assessment. No major adverse events were reported, indicating that sirolimus was well tolerated and safe. Analysis of peripheral blood Treg cell percentages in both the control and ITP showed no significant difference before treatment. The percentage of Treg cells increased after treatment with sirolimus, suggesting that sirolimus increases Treg cells. These findings suggest that sirolimus serves as an effective second-line treatment option for ITP, demonstrating favorable clinical efficacy.

The dual role of mesenchymal stem cells in apoptosis regulation

Mesenchymal stem cells (MSCs) are widely distributed pluripotent stem cells with powerful immunomodulatory capacity. MSCs transplantation therapy (MSCT) is widely used in the fields of tissue regeneration and repair, and treatment of inflammatory diseases. Apoptosis is an important way for tissues to maintain cell renewal, but it also plays an important role in various diseases. And many studies have shown that MSCs improves the diseases by regulating cell apoptosis. The regulation of MSCs on apoptosis is double-sided. On the one hand, MSCs significantly inhibit the apoptosis of diseased cells. On the other hand, MSCs also promote the apoptosis of tumor cells and excessive immune cells. Furthermore, MSCs regulate apoptosis through multiple molecules and pathways, including three classical apoptotic signaling pathways and other pathways. In this review, we summarize the current evidence on the regulation of apoptosis by MSCs.

Recent advancement of autophagy in polyploid giant cancer cells and its interconnection with senescence and stemness for therapeutic opportunities

Recurrent chemotherapy-induced senescence and resistance are attributed to the polyploidization of cancer cells that involve genomic instability and poor prognosis due to their unique form of cellular plasticity. Autophagy, a pre-dominant cell survival mechanism, is crucial during carcinogenesis and chemotherapeutic stress, favouring polyploidization. The selective autophagic degradation of essential proteins associated with cell cycle progression checkpoints deregulate mitosis fidelity and genomic integrity, imparting polyploidization of cancer cells. In connection with cytokinesis failure and endoreduplication, autophagy promotes the formation, maintenance, and generation of the progeny of polyploid giant cancer cells. The polyploid cancer cells embark on autophagy-guarded elevation in the expression of stem cell markers, along with triggered epithelial and mesenchymal transition and senescence. The senescent polyploid escapers represent a high autophagic index than the polyploid progeny, suggesting regaining autophagy induction and subsequent autophagic degradation, which is essential for escaping from senescence/polyploidy, leading to a higher proliferative phenotypic progeny. This review documents the various causes of polyploidy and its consequences in cancer with relevance to autophagy modulation and its targeting for therapeutic intervention as a novel therapeutic strategy for personalized and precision medicine.

Exosome/antimicrobial peptide laden hydrogel wound dressings promote scarless wound healing through miR-21-5p-mediated multiple functions

Mesenchymal stem cell (MSC)-based therapy is an effective strategy for regenerative therapy. However, safety and ease of use are still issues to be overcome in clinical applications. Exosomes are naturally derived nanoparticles containing bioactive molecules, which serve as ideal cell-free therapeutic modalities. However, issues such as delivery, long-term preservation and activity maintenance of exosomes are other problems that limit their application. In this study, we proposed the use of rapid freeze-dry-thaw macroporous hydrogels for the encapsulation of HucMSC-derived exosomes (HucMSC-Exos) combined with an antimicrobial peptide coating. This exosome-encapsulated hyaluronic acid macroporous hydrogel HD-DP7/Exo can achieve long-term storage and transport by lyophilization and can be rapidly redissolved for treatment. After comprehensively comparing the therapeutic effects of HucMSC-Exos and HucMSC-loaded hydrogels, we found that HucMSC-Exos could also effectively regulate fibroblasts, vascular endothelial cells, and macrophages and inhibit myofibroblast-mediated fibrosis, thus promoting tissue regeneration and inhibiting scar formation in a mouse model of deep second-degree burn infection healing. These properties of lyophilized storage and whole-process-repair make HD-DP7/Exo have potential application value and application prospects.

Specific lipid magnetic sphere sorted CD146-positive bone marrow mesenchymal stem cells can better promote articular cartilage damage repair

BACKGROUND

The characteristics and therapeutic potential of subtypes of bone marrow mesenchymal stem cells (BMSCs) are largely unknown. Also, the application of subpopulations of BMSCs in cartilage regeneration remains poorly characterized. The aim of this study was to explore the regenerative capacity of CD146-positive subpopulations of BMSCs for repairing cartilage defects.

METHODS

CD146-positive BMSCs (CD146 + BMSCs) were sorted by self-developed CD146-specific lipid magnetic spheres (CD146-LMS). Cell surface markers, viability, and proliferation were evaluated in vitro. CD146 + BMSCs were subjected to in vitro chondrogenic induction and evaluated for chondrogenic properties by detecting mRNA and protein expression. The role of the CD146 subpopulation of BMSCs in cartilage damage repair was assessed by injecting CD146 + BMSCs complexed with sodium alginate gel in the joints of a mouse cartilage defect model.

RESULTS

The prepared CD146-LMS had an average particle size of 193.7 ± 5.24 nm, an average potential of 41.9 ± 6.21 mv, and a saturation magnetization intensity of 27.2 Am2/kg, which showed good stability and low cytotoxicity. The sorted CD146 + BMSCs highly expressed stem cell and pericyte markers with good cellular activity and cellular value-added capacity. Cartilage markers Sox9, Collagen II, and Aggrecan were expressed at both protein and mRNA levels in CD146 + BMSCs cells after chondrogenic induction in vitro. In a mouse cartilage injury model, CD146 + BMSCs showed better function in promoting the repair of articular cartilage injury.

CONCLUSION

The prepared CD146-LMS was able to sort out CD146 + BMSCs efficiently, and the sorted subpopulation of CD146 + BMSCs had good chondrogenic differentiation potential, which could efficiently promote the repair of articular cartilage injury, suggesting that the sorted CD146 + BMSCs subpopulation is a promising seed cell for cartilage tissue engineering.

Vibrational phenomics decoding of the stem cell stepwise aging process at single-cell resolution

We introduce vibrational spectroscopy to quantitatively measure the phenotypic heterogeneity of senescent stem cells in the aging process at the single cell level. Using an aging model of serially passaged human mesenchymal stem cells (MSCs), we characterized the phenotypic changes of MSCs during different aged stages and discovered a stepwise aging process with several distinct subtypes.

Mapping the Cellular Biogeography of Human Bone Marrow Niches Using Single-Cell Transcriptomics and Proteomic Imaging

The bone marrow is the organ responsible for blood production. Diverse non-hematopoietic cells contribute essentially to hematopoiesis. However, these cells and their spatial organization remain largely uncharacterized as they have been technically challenging to study in humans. Here, we used fresh femoral head samples and performed single-cell RNA sequencing (scRNA-Seq) to profile 29,325 enriched non-hematopoietic bone marrow cells and discover nine transcriptionally distinct subtypes. We next employed CO-detection by inDEXing (CODEX) multiplexed imaging of 18 individuals, including both healthy and acute myeloid leukemia (AML) samples, to spatially profile over one million single cells with a novel 53-antibody panel. We discovered a relatively hyperoxygenated arterio-endosteal niche for early myelopoiesis, and an adipocytic, but not endosteal or perivascular, niche for early hematopoietic stem and progenitor cells. We used our atlas to predict cell type labels in new bone marrow images and used these predictions to uncover mesenchymal stromal cell (MSC) expansion and leukemic blast/MSC-enriched spatial neighborhoods in AML patient samples. Our work represents the first comprehensive, spatially-resolved multiomic atlas of human bone marrow and will serve as a reference for future investigation of cellular interactions that drive hematopoiesis.

MSCsDB: a database of single-cell transcriptomic profiles and in-depth comprehensive analyses of human mesenchymal stem cells

Mesenchymal stem cells (MSCs) possess multipotent properties that make them promising candidates for immunomodulation and regenerative medicine. However, MSC heterogeneity poses challenges to their research reproducibility and clinical application. The emergence of single-cell RNA sequencing (scRNA-seq) technology has enabled a thorough examination of MSC heterogeneity, underscoring the necessity for a specialized platform to systematically analyze the published datasets derived from MSC scRNA-seq experiments. However, large-scale integration and in-depth exploration of MSC scRNA-seq datasets to comprehensively depict their developmental patterns, relationships, and knowledge are still lacking. Here, we present MSCsDB ( http://mscsdb.jflab.ac.cn:18088/index/ ), an interactive database that has been constructed using high-quality scRNA-seq datasets from all published sources on MSCs. MSCsDB provides a one-stop interactive query for regulon activities, gene ontology enrichment, signature gene visualization and transcription factor regulon analysis. Additionally, the dedicated module within MSCsDB was developed to facilitate the evaluation of MSC quality, thereby promoting the standardization of MSC subtype usage. Notably, MSCsDB enables users to analyze their MSCs scRNA-seq data directly, yielding visually appealing outputs of exceptional quality that can be conveniently downloaded via email. Furthermore, MSCsDB integrates the current comprehensive MSC atlas taxonomy, which includes 470,000 cells and 5 tissues from 26 subjects, as publicly available references. These references provide molecular characterization and phenotypic prediction for annotating MSC subsets. In summary, MSCsDB serves as a user-friendly and contemporary data repository for human MSCs, offering a dedicated platform that enables users to effectively conduct comprehensive analyses on their individual MSCs scRNA-seq data.

Single-Cell Transcriptomics Reveals the Ameliorative Effect of Oridonin on Septic Liver Injury

Sepsis is a life-threatening syndrome leading to hemodynamic instability and potential organ dysfunction. Oridonin, commonly used in Traditional Chinese Medicine (TCM), exhibits significant anti-inflammation activity. To explore the protective mechanisms of oridonin against the pathophysiological changes, the authors conducted single-cell transcriptome (scRNA-seq) analysis on septic liver models induced by cecal ligation and puncture (CLP). They obtained a total of 63,486 cells, distributed across 11 major cell clusters, and concentrated their analysis on four specific clusters (hepatocytes/Heps, macrophages, endothelial/Endos and T/NK) based on their changes in proportion during sepsis and under oridonin treatment. Firstly, biological changes in Hep, which are related to metabolic dysregulation and pro-inflammatory signaling, are observed during sepsis. Secondly, they uncovered the dynamic profiles of macrophage's phenotype, indicating that a substantial number of macrophages exhibited a M1-skewed phenotype associated with pro-inflammatory characteristics in septic model. Thirdly, they detected an upregulation of both inflammatory cytokines and transcriptomic factor Nfkb1 expression within Endo, along with slight capillarization during sepsis. Moreover, excessive accumulation of cytotoxic NK led to an immune imbalance. Though, oridonin ameliorated inflammatory-related responses and improved the liver dysfunction in septic mice. This study provides fundamental evidence of the protective effects of oridonin against sepsis-induced cytokine storm.

Therapeutic potential of adipose derived stromal cells for major skin inflammatory diseases

Inflammatory skin diseases like psoriasis and atopic dermatitis are chronic inflammatory skin conditions continuously under investigation due to increased prevalence and lack of cure. Moreover, long-term treatments available are often associated with adverse effects and drug resistance. Consequently, there is a clear unmet need for new therapeutic approaches. One promising and cutting-edge treatment option is the use of adipose-derived mesenchymal stromal cells (AD-MSCs) due to its immunomodulatory and anti-inflammatory properties. Therefore, this mini review aims to highlight why adipose-derived mesenchymal stromal cells are a potential new treatment for these diseases by summarizing the pre-clinical and clinical studies investigated up to date and addressing current limitations and unresolved clinical questions from a dermatological and immunomodulatory point of view.

Stemness properties of SSEA-4+ subpopulation isolated from heterogenous Wharton's jelly mesenchymal stem/stromal cells

Background: High heterogeneity of mesenchymal stem/stromal cells (MSCs) due to different degrees of differentiation of cell subpopulations poses a considerable challenge in preclinical studies. The cells at a pluripotent-like stage represent a stem cell population of interest for many researchers worldwide, which is worthy of identification, isolation, and functional characterization. In the current study, we asked whether Wharton's jelly-derived MSCs (WJ-MSCs) which express stage-specific embryonic antigen-4 (SSEA-4) can be considered as a pluripotent-like stem cell population. Methods: SSEA-4 expression in different culture conditions was compared and the efficiency of two cell separation methods were assessed: Magnetic Activated Cell Sorting (MACS) and Fluorescence Activated Cell Sorting (FACS). After isolation, SSEA-4+ cells were analyzed for the following parameters: the maintenance of the SSEA-4 antigen expression after cell sorting, stem cell-related gene expression, proliferation potential, clonogenicity, secretome profiling, and the ability to form spheres under 3D culture conditions. Results: FACS allowed for the enrichment of SSEA-4+ cell content in the population that lasted for six passages after sorting. Despite the elevated expression of stemness-related genes, SSEA-4+ cells neither differed in their proliferation and clonogenicity potential from initial and negative populations nor exhibited pluripotent differentiation repertoire. SSEA-4+ cells were observed to form smaller spheroids and exhibited increased survival under 3D conditions. Conclusion: Despite the transient expression of stemness-related genes, our findings could not fully confirm the undifferentiated pluripotent-like nature of the SSEA-4+ WJ-MSC population cultured in vitro.

Mesenchymal stromal cells derived from various tissues: Biological, clinical and cryopreservation aspects: Update from 2015 review

Mesenchymal stromal cells (MSCs) have become one of the most investigated and applied cells for cellular therapy and regenerative medicine. In this update of our review published in 2015, we show that studies continue to abound regarding the characterization of MSCs to distinguish them from other similar cell types, the discovery of new tissue sources of MSCs, and the confirmation of their properties and functions that render them suitable as a therapeutic. Because cryopreservation is widely recognized as the only technology that would enable the on-demand availability of MSCs, here we show that although the traditional method of cryopreserving cells by slow cooling in the presence of 10% dimethyl sulfoxide (Me2SO) continues to be used by many, several novel MSC cryopreservation approaches have emerged. As in our previous review, we conclude from these recent reports that viable and functional MSCs from diverse tissues can be recovered after cryopreservation using a variety of cryoprotectants, freezing protocols, storage temperatures, and periods of storage. We also show that for logistical reasons there are now more studies devoted to the cryopreservation of tissues from which MSCs are derived. A new topic included in this review covers the application in COVID-19 of MSCs arising from their immunomodulatory and antiviral properties. Due to the inherent heterogeneity in MSC populations from different sources there is still no standardized procedure for their isolation, identification, functional characterization, cryopreservation, and route of administration, and not likely to be a "one-size-fits-all" approach in their applications in cell-based therapy and regenerative medicine.

MicroRNA-based therapies: Revolutionizing the treatment of acute myeloid leukemia

MicroRNAs (miRNAs) are small noncoding epigenetic regulators that exert critical significance by influencing target mRNAs and governing gene expression patterns and cellular signaling pathways. miRNAs play a pivotal role in a wide array of biological processes, including cell differentiation, proliferation, and survival. Numerous miRNAs contribute to tumorigenesis and cancer progression by promoting tumor growth, angiogenesis, invasion, and immune evasion, while others exert tumor suppressive effects. From a clinical perspective, it has been demonstrated that numerous miRNAs are related to the prognosis in acute myeloid leukemia (AML) patients. They hold the potential to be utilized as biomarkers, aiding in improved treatment decision-making. Moreover, a number of preclinical investigations have offered compelling evidence to create novel treatment approaches that target miRNAs in AML. This review highlights the clinical significance of miRNAs in the diagnosis, prognosis, and treatment response of adult patients with AML.

The ncBAF Complex Regulates Transcription in AML Through H3K27ac Sensing by BRD9

The non-canonical BAF complex (ncBAF) subunit BRD9 is essential for acute myeloid leukemia (AML) cell viability but has an unclear role in leukemogenesis. Because BRD9 is required for ncBAF complex assembly through its DUF3512 domain, precise bromodomain inhibition is necessary to parse the role of BRD9 as a transcriptional regulator from that of a scaffolding protein. To understand the role of BRD9 bromodomain function in regulating AML, we selected a panel of five AML cell lines with distinct driver mutations, disease classifications, and genomic aberrations and subjected these cells to short-term BRD9 bromodomain inhibition. We examined the bromodomain-dependent growth of these cell lines, identifying a dependency in AML cell lines but not HEK293T cells. To define a mechanism through which BRD9 maintains AML cell survival, we examined nascent transcription, chromatin accessibility, and ncBAF complex binding genome-wide after bromodomain inhibition. We identified extensive regulation of transcription by BRD9 bromodomain activity, including repression of myeloid maturation factors and tumor suppressor genes, while standard AML chemotherapy targets were repressed by inhibition of the BRD9 bromodomain. BRD9 bromodomain activity maintained accessible chromatin at both gene promoters and gene-distal putative enhancer regions, in a manner that qualitatively correlated with enrichment of BRD9 binding. Furthermore, we identified reduced chromatin accessibility at GATA, ETS, and AP-1 motifs and increased chromatin accessibility at SNAIL-, HIC-, and TP53-recognized motifs after BRD9 inhibition. These data suggest a role for BRD9 in regulating AML cell differentiation through modulation of accessibility at hematopoietic transcription factor binding sites.

SIGNIFICANCE

The bromodomain-containing protein BRD9 is essential for AML cell viability, but it is unclear whether this requirement is due to the protein's role as an epigenetic reader. We inhibited this activity and identified altered gene-distal chromatin regulation and transcription consistent with a more mature myeloid cell state.

Quantitative association between gene expression and blood cell production of individual hematopoietic stem cells in mice

Individual hematopoietic stem cells (HSCs) produce different amounts of blood cells upon transplantation. Taking advantage of the intercellular variation, we developed an experimental and bioinformatic approach to evaluating the quantitative association between gene expression and blood cell production across individual HSCs. We found that most genes associated with blood production exhibit the association only at some levels of blood production. By mapping gene expression with blood production, we identified four distinct patterns of their quantitative association. Some genes consistently correlate with blood production over a range of levels or across all levels, and these genes are found to regulate lymphoid but not myeloid production. Other genes exhibit one or more clear peaks of association. Genes with overlapping peaks are found to be coexpressed in other tissues and share similar molecular functions and regulatory motifs. By dissecting intercellular variations, our findings revealed four quantitative association patterns that reflect distinct dose-response molecular mechanisms modulating the blood cell production of HSCs.

Mesenchymal stem cells (MSCs) from the mouse bone marrow show differential expression of interferon regulatory factors IRF-1 and IRF-2

BACKGROUND

Interferon regulatory factors (IRF-1 and IRF-2) are transcription factors widely implicated in various cellular processes, including regulation of inflammatory responses to pathogens, cell proliferation, oncogenesis, differentiation, autophagy, and apoptosis.

METHODS

We have studied the expression of IRF-1, IRF-2 mRNAs by RT-PCR, cellular localization of the proteins by immunofluorescence, and expression of mRNAs of genes regulated by IRF-1, IRF-2 by RT-PCR in mouse bone marrow cells (BMCs) and mesenchymal stem cells (MSCs).

RESULTS

Higher level of IRF-1 mRNA was observed in BMCs and MSCs compared to that of IRF-2. Similarly, differential expression of IRF-1 and IRF-2 proteins was observed in BMCs and MSCs. IRF-1 was predominantly localized in the cytoplasm, whereas IRF-2 was localized in the nuclei of BMCs. MSCs showed nucleo-cytoplasmic distribution of IRF-1 and nuclear localization of IRF-2. Constitutive expression of IRF-1 and IRF-2 target genes: monocyte chemoattractant protein-1 (MCP-1), vascular cell adhesion molecule-1 (VCAM-1), cyclooxygenase-2 (COX-2), matrix metalloproteinase-9 (MMP-9), and caspase-1 was observed in both BMCs and MSCs. MSCs showed constitutive expression of the pluripotency-associated factors, Oct3/4 and Sox-2. Lipopolysaccharide (LPS)-treatment of MSCs induced prominent cellular localization of IRF-1 and IRF-2.

CONCLUSIONS

Our results suggest that IRF-1 and IRF-2 exhibit differential expression of their mRNAs and subcellular localization of the proteins in BMCs and MSCs. These cells also show differential levels of constitutive expression of IRF-1 and IRF-2 target genes. This may regulate immune-responsive properties of BMCs and MSCs through IRF-1, IRF-2-dependent gene expression and protein-protein interaction. Regulating IRF-1 and IRF-2 may be helpful for immunomodulatory functions of MSCs for cell therapy and regenerative medicine.

Application progress of single-cell sequencing technology in mesenchymal stem cells research

Single-Cell Sequencing (SCS) technology plays an important role in the field of Mesenchymal Stem Cells (MSCs) research. This paper comprehensively describes the application of SCS technology in the field of MSCs research, including (1) SCS enables more precise MSCs characterization and biomarker definition. (2) SCS reveals the prevalent gene expression heterogeneity among different subclusters within MSCs, which contributes to a more comprehensive understanding of MSCs function and diversity in developmental, regenerative, and pathological contexts. (3) SCS provides insights into the dynamic transcriptional changes experienced by MSCs during differentiation and the complex web of important signaling pathways and regulatory factors controlling key processes within MSCs, including proliferation, differentiation and regulation, and interactions mechanisms. (4) The analytical methods underpinning SCS data are rapidly evolving and converging with the field of histological research to systematically deconstruct the functions and mechanisms of MSCs. This review provides new perspectives for unraveling the biological properties, heterogeneity, differentiation potential, biological functions, and clinical potential of MSCs at the single-cell level.

Development and Clinical Applications of PI3K/AKT/mTOR Pathway Inhibitors as a Therapeutic Option for Leukemias

Leukemias are hematological neoplasms characterized by dysregulations in several cellular signaling pathways, prominently including the PI3K/AKT/mTOR pathway. Since this pathway is associated with several important cellular mechanisms, such as proliferation, metabolism, survival, and cell death, its hyperactivation significantly contributes to the development of leukemias. In addition, it is a crucial prognostic factor, often correlated with therapeutic resistance. Changes in the PI3K/AKT/mTOR pathway are identified in more than 50% of cases of acute leukemia, especially in myeloid lineages. Furthermore, these changes are highly frequent in cases of chronic lymphocytic leukemia, especially those with a B cell phenotype, due to the correlation between the hyperactivation of B cell receptors and the abnormal activation of PI3Kδ. Thus, the search for new therapies that inhibit the activity of the PI3K/AKT/mTOR pathway has become the objective of several clinical studies that aim to replace conventional oncological treatments that have high rates of toxicities and low specificity with target-specific therapies offering improved patient quality of life. In this review we describe the PI3K/AKT/mTOR signal transduction pathway and its implications in leukemogenesis. Furthermore, we provide an overview of clinical trials that employed PI3K/AKT/mTOR inhibitors either as monotherapy or in combination with other cytotoxic agents for treating patients with various types of leukemias. The varying degrees of treatment efficacy are also reported.

Exosomes derived from CD271+CD56+ bone marrow mesenchymal stem cell subpopoulation identified by single-cell RNA sequencing promote axon regeneration after spinal cord injury

Rationale: Spinal cord injury (SCI) results in neural tissue damage. However, the limited regenerative capacity of adult mammals' axons upon SCI leads to persistent neurological dysfunction. Thus, exploring the pathways that can enhance axon regeneration in injured spinal cord is of great significance. Methods: Through the utilization of single-cell RNA sequencing in this research, a distinct subpopulation of bone marrow mesenchymal stem cells (BMSCs) that exhibits the capacity to facilitate axon regeneration has been discovered. Subsequently, the CD271+CD56+ BMSCs subpopulation was isolated using flow cytometry, and the exosomes derived from this subpopulation (CD271+CD56+ BMSC-Exos) were extracted and incorporated into a hydrogel to create a sustained release system. The aim was to investigate the therapeutic effects of CD271+CD56+ BMSC-Exos and elucidate the underlying mechanisms involved in promoting axon regeneration and neural function recovery. Results: The findings indicate that CD271+CD56+ BMSC-Exos share similar physical and chemical properties with conventional exosomes. Importantly, in an SCI model, in situ implantation of CD271+CD56+ BMSC-Exos hydrogel resulted in increased expression of NF and synaptophysin, markers associated with axon regeneration and synapse formation, respectively. This intervention also contributed to improved neural function recovery. In vitro experiments demonstrated that CD271+CD56+ BMSC-Exos treatment significantly enhanced axon extension distance and increased the number of branches in dorsal root ganglion axons. Moreover, further investigation into the molecular mechanisms underlying CD271+CD56+ BMSC-Exos-mediated axon regeneration revealed the crucial involvement of the miR-431-3p/RGMA axis. Conclusion: In summary, the implantation of CD271+CD56+ BMSC-Exos hydrogel presents a promising and effective therapeutic approach for SCI.

Transcriptomic Analysis of the Aged Nulliparous Mouse Ovary Suggests a Stress State That Promotes Pro-Inflammatory Lipid Signaling and Epithelial Cell Enrichment

Ovarian cancer (OC) incidence and mortality peaks at post-menopause while OC risk is either reduced by parity or increased by nulliparity during fertile life. The long-term effect of nulliparity on ovarian gene expression is largely unknown. In this study, we describe a bioinformatic/data-mining analysis of 112 coding genes upregulated in the aged nulliparous (NP) mouse ovary compared to the aged multiparous one as reference. Canonical gene ontology and pathway analyses indicated a pro-oxidant, xenobiotic-like state accompanied by increased metabolism of inflammatory lipid mediators. Up-regulation of typical epithelial cell markers in the aged NP ovary was consistent with synchronized overexpression of Cldn3, Ezr, Krt7, Krt8 and Krt18 during the pre-neoplastic phase of mOSE cell cultures in a former transcriptome study. In addition, 61/112 genes were upregulated in knockout mice for Fshr and for three other tumor suppressor genes (Pten, Cdh1 and Smad3) known to regulate follicular homeostasis in the mammalian ovary. We conclude that the aged NP ovary displays a multifaceted stress state resulting from oxidative imbalance and pro-inflammatory lipid signaling. The enriched epithelial cell content might be linked to follicle depletion and is consistent with abundant clefts and cysts observed in aged human and mouse ovaries. It also suggests a mesenchymal-to-epithelial transition in the mOSE of the aged NP ovary. Our analysis suggests that in the long term, nulliparity worsens a variety of deleterious effects of aging and senescence thereby increasing susceptibility to cancer initiation in the ovary.

CD146-positive adipose-derived stem cells subpopulation enriched by albumin magnetic sphere ameliorates knee osteoarthritis pain and promotes cartilage repair

BACKGROUND

The use of adipose stem cell (ADSCs) subpopulations in cartilage repair remains poorly characterized. In this study, we constructed an albumin magnetic sphere with specific targeting of CD146 (CD146-AMs) for sorting a subpopulation of CD146-positive ADSCs (CD146 + ADSCs) and explored the role of CD146 + ADSCs on joint pain and cartilage repair in rats with knee osteoarthritis (KOA).

METHODS

CD146-AMs were prepared and analyzed in materialistic characterization tests. Subpopulations of CD146 + ADSCs were sorted using CD146-AMs. Surface labeling, viability, and proliferation of a subpopulation of CD146 + ADSCs were evaluated in vitro. Molecular characterization of mRNA and protein expression profiles was analyzed by microarray. A rat KOA pain model was established by the iodoacetic acid method, and KOA pain and the promotion of cartilage repair were assessed after treatment with bilateral joint cavity injections of CD146 + ADSCs.

RESULTS

The CD146-AMs prepared in this study had an average particle size of 242.63 ± 6.74 nm, an average potential of 33.82 ± 3.53 mv, and high CD146 targeting and low cytotoxicity. The positive rate of enriched CD146 + ADSCs was 98.21% and showed a high level of stem cell marker expression and good cell viability. Gene and protein expression profiles showed that CD146 + ADSCs have different cellular functions, especially in regulating inflammation. In the KOA model, low, medium and high concentrations of CD146 + ADSCs were able to improve KOA pain and promote cartilage repair in a concentration-dependent trend.

CONCLUSIONS

The CD146-AMs prepared in this study were able to safely and efficiently sort out the CD146 + ADSCs subpopulation. The subpopulation of CD146 + ADSCs has a unique molecular profile that ameliorates KOA pain and repairs cartilage damage in rats, providing a new idea for KOA treatment.

A phase 2 and pharmacological study of sapanisertib in patients with relapsed and/or refractory acute lymphoblastic leukemia

BACKGROUND

Despite recent approval of several new agents, relapsed acute lymphoblastic leukemia (ALL) remains challenging to treat. Sapanisertib (MLN0128/TAK-228) is an oral TORC1/2 inhibitor that exhibited preclinical activity against ALL.

METHODS

We conducted a single-arm multi-center Phase II study of sapanisertib monotherapy (3 mg orally daily of the milled formulation for 21 days every 28 days) in patients with ALL through the Experimental Therapeutics Clinical Trials Network (NCI-9775).

RESULTS

Sixteen patients, 15 of whom were previously treated (median 3 prior lines of therapy), were enrolled. Major grade 3-4 non-hematologic toxicities included mucositis (3 patients) and hyperglycemia (2 patients) as well as hepatic failure, seizures, confusion, pneumonitis, and anorexia (1 patient each). Grade >2 hematological toxicity included leukopenia (3), lymphopenia (2), thrombocytopenia, and neutropenia (1). The best response was stable disease in 2 patients (12.5%), while only 3 patients (19%) were able to proceed to Cycle 2. Pharmacokinetic analysis demonstrated drug exposures similar to those observed in solid tumor patients. Immunoblotting in serially collected samples indicated limited impact of treatment on phosphorylation of mTOR pathway substrates such as 4EBP1, S6, and AKT.

CONCLUSION

In summary, single-agent sapanisertib had a good safety profile but limited target inhibition or efficacy in ALL as a single agent. This trial was registered at ClinicalTrials.gov as NCT02484430.

Optimizing the therapeutic window of sirolimus by monitoring blood concentration for the treatment of immune thrombocytopenia

Previous studies have demonstrated that sirolimus (SRL) is an effective agent for the treatment of refractory/relapsed (R/R) ITP. However, the therapeutic window of sirolimus in the treatment of ITP has not been established. As the toxicity of sirolimus increases with higher blood concentrations, it is crucial to determine the optimal therapeutic concentration of SRL for the treatment of ITP. Thus, in this study, we used a retrospective cohort of ITP patients treated with sirolimus to propose the therapeutic dosage window for sirolimus. A total of 275 laboratory results of SRL blood concentration from 63 ITP patients treated with SRL were analyzed retrospectively. The ITP patients were divided into five groups based on their SRL blood concentration: 0-4 ng/ml, 4-8 ng/ml, 8-12 ng/ml, 12-16 ng/ml and ≥16 ng/ml. In addition to the SRL blood concentration, platelet counts and adverse events that occurred during the first 6 weeks of SRL treatment were analyzed. These findings were then used to establish the decision matrix tables and ROC curves, which helped identify the therapeutic window of SRL. Based on the values and trends of true-positive rate (TPR) and false-positive rate (FPR) in the ROC curve, patients who achieved a SRL blood concentration of 4-12 ng/ml displayed a higher response rate compared to those with a SRL concentration of 0-4 ng/ml or ≥16ng/ml. Additionally, the response rate was better for patients with a SRL concentration of 8-12 ng/ml compared to 4-8 ng/ml. Adverse events were related to the concentration of SRL; however, there was no significant difference in the incidence of adverse events between the concentrations of 4-8 ng/ml and 8-12 ng/ml (P > .05). Regression analysis suggested that the concentration of SRL correlated with the patient's age, PLT count at the start of SRL administration, and the dose of SRL. It is suggested that the optimal blood concentration of SRL monotherapy for managing ITP is 8-12 ng/ml. This range may achieve a favorable balance between clinical efficacy and the severity of adverse events.

Sirolimus is effective for primary refractory/relapsed warm autoimmune haemolytic anaemia/Evans syndrome: a retrospective single-center study

BACKGROUND

Some patients with warm autoimmune haemolytic anaemia (wAIHA) or Evans syndrome (ES) have no response to glucocorticoid or relapse. Recent studies found that sirolimus was effective in autoimmune cytopenia with a low relapse rate.

METHODS

Data from patients with refractory/relapsed wAIHA and ES in Peking Union Medical College Hospital from July 2016 to May 2022 who had been treated with sirolimus for at least 6 months and followed up for at least 12 months were collected retrospectively. Baseline and follow-up clinical data were recorded and the rate of complete response (CR), partial response (PR) at different time points, adverse events, relapse, outcomes, and factors that may affect the efficacy and relapse were analyzed.

RESULTS

There were 44 patients enrolled, with 9 (20.5%) males and a median age of 44 (range: 18-86) years. 37 (84.1%) patients were diagnosed as wAIHA, and 7 (15.9%) as ES. Patients were treated with sirolimus for a median of 23 (range: 6-80) months and followed up for a median of 25 (range: 12-80) months. 35 (79.5%) patients responded to sirolimus, and 25 (56.8%) patients achieved an optimal response of CR. Mucositis (11.4%), infection (9.1%), and alanine aminotransferase elevation (9.1%) were the most common adverse events. 5/35 patients (14.3%) relapsed at a median of 19 (range: 15-50) months. Patients with a higher sirolimus plasma trough concentration had a higher overall response (OR) and CR rate (p = 0.009, 0.011, respectively). At the time of enrolment, patients were divided into two subgroups that relapsed or refractory to glucocorticoid, and the former had poorer relapse-free survival (p = 0.032) than the other group.

CONCLUSION

Sirolimus is effective for patients with primary refractory/relapsed wAIHA and ES, with a low relapse rate and mild side effects. Patients with a higher sirolimus plasma trough concentration had a higher OR and CR rate, and patients who relapsed to glucocorticoid treatment had poorer relapse-free survival than those who were refractory.

Mesenchymal stem cells under epigenetic control - the role of epigenetic machinery in fate decision and functional properties

Mesenchymal stem cells (mesenchymal stromal cells, MSC) are multipotent stem cells that can differentiate into cells of at least three mesodermal lineages, namely adipocytes, osteoblasts, and chondrocytes, and have potent immunomodulatory properties. Epigenetic modifications are critical regulators of gene expression and cellular differentiation of mesenchymal stem cells (MSCs). Epigenetic machinery controls MSC differentiation through direct modifications to DNA and histones. Understanding the role of epigenetic machinery in MSC is crucial for the development of effective cell-based therapies for degenerative and inflammatory diseases. In this review, we summarize the current understanding of the role of epigenetic control of MSC differentiation and immunomodulatory properties.

Single-cell transcriptome analysis reveals the effectiveness of cytokine priming irrespective of heterogeneity in mesenchymal stromal cells

BACKGROUND AIMS

Mesenchymal stromal cells (MSCs) are recognized as a potential cell-based therapy for regenerative medicine. Short-term inflammatory cytokine pre-stimulation (cytokine priming) is a promising approach to enhance regenerative efficacy of MSCs. However, it is unclear whether their intrinsic heterogenic nature causes an unequal response to cytokine priming, which might blunt the accessibility of clinical applications.

METHODS

In this study, by analyzing the single-cell transcriptomic landscape of human bone marrow MSCs from a naïve to cytokine-primed state, we elucidated the potential mechanism of superior therapeutic potential in cytokine-primed MSCs.

RESULTS

We found that cytokine-primed MSCs had a distinct transcriptome landscape. Although substantial heterogeneity was identified within the population in both naïve and primed states, cytokine priming enhanced the several characteristics of MSCs associated with therapeutic efficacy irrespective of heterogeneity. After cytokine-priming, all sub-clusters of MSCs possessed high levels of immunoregulatory molecules, trophic factors, stemness-related genes, anti-apoptosis markers and low levels of multi-lineage and senescence signatures, which are critical for their therapeutic potency.

CONCLUSIONS

In conclusion, our results provide new insights into MSC heterogeneity under cytokine stimulation and suggest that cytokine priming reprogrammed MSCs independent of heterogeneity.

A single-cell transcriptomic atlas characterizes age-related changes of murine cranial stem cell niches

The craniofacial bones provide structural support for the skull and accommodate the vulnerable brain tissue with a protective cavity. The bone tissue undergoes constant turnover, which relies on skeletal stem cells (SSCs) and/or mesenchymal stem cells (MSCs) and their niches. SSCs/MSCs and their perivascular niche within the bone marrow are well characterized in long bones. As for cranial bones, besides bone marrow, the suture mesenchyme has been identified as a unique niche for SSCs/MSCs of craniofacial bones. However, a comprehensive study of the two different cranial stem cell niches at single-cell resolution is still lacking. In addition, during the progression of aging, age-associated changes in cranial stem cell niches and resident cells remain uncovered. In this study, we investigated age-related changes in cranial stem cell niches via single-cell RNA sequencing (scRNA-seq). The transcriptomic profiles and cellular compositions have been delineated, indicating alterations of the cranial bone marrow microenvironment influenced by inflammaging. Moreover, we identified a senescent mesenchymal cell subcluster and several age-related immune cell subclusters by reclustering and pseudotime trajectory analysis, which might be closely linked to inflammaging. Finally, differentially expressed genes (DEGs) and cell-cell communications were analyzed during aging, revealing potential regulatory factors. Overall, this work highlights the age-related changes in cranial stem cell niches, which deepens the current understanding of cranial bone and suture biology and may provide therapeutic targets for antiaging and regenerative medicine.

Polyploid cell dynamics and death before and after PEG-treatment of a NIH/3T3 derived culture: vinblastine effects on the regulation of cell subpopulations heterogeneity

BACKGROUND

Neoplastic subpopulations can include polyploid cells that can be involved in tumor evolution and recurrence. Their origin can be traced back to the tumor microenvironment or chemotherapeutic treatment, which can alter cell division or favor cell fusion, generating multinucleated cells. Their progeny, frequently genetically unstable, can result in new aggressive and more resistant to chemotherapy subpopulations. In our work, we used NIHs cells, previously derived from the NIH/3T3 line after serum deprivation, that induced a polyploidization increase with the appearance of cells with DNA content ranging from 4 to 24c. This study aimed to analyze the cellular dynamics of NIHs culture subpopulations before and after treatment with the fusogenic agent polyethylene glycol (PEG), which allowed us to obtain new giant polyploid cells. Successively, PEG-untreated and PEG-treated cultures were incubated with the antimicrotubular poison vinblastine. The dynamics of appearance, decrease and loss of cell subpopulations were evaluated by correlating cell DNA content to mono-multinuclearity resulting from cell fusion and division process alteration and to the peculiarities of cell death events.

RESULTS

DNA microfluorimetry and morphological techniques (phase contrast, fluorescence and TEM microscopies) indicated that PEG treatment induced a 4-24c cell increase and the appearance of new giant elements (64-140c DNA content). Ultrastructural analysis and autophagosomal-lysosomal compartment fluorochromization, which allowed us to correlate cytoplasmic changes to death events, indicated that cell depletion occurred through distinct mechanisms: apoptotic death involved 2c, 4c and 8c cells, while autophagic-like death involved intermediate 12-24c cells, showing nuclear (lobulation/micronucleation) and autophagic cytoplasm alterations. Death, spontaneously occurring, especially in intermediate-sized cells, was increased after vinblastine treatment. No evident cell loss by death events was detected in the 64-140c range.

CONCLUSIONS

PEG-treated NIHs cultures can represent a model of heterogeneous subpopulations originating from cell fusion and division process anomalies. Altogether, our results suggest that the different cell dynamics of NIHs subpopulations can affect the variability of responses to stimuli able to induce cell degeneration and death. Apoptptic, autophagic or hybrid forms of cell death can also depend on the DNA content and ability to progress through the cell cycle, which may influence the persistence and fate of polyploid cell descendants, also concerning chemotherapeutic agent action.

Polyploidy, EZH2 upregulation, and transformation in cytomegalovirus-infected human ovarian epithelial cells

Human cytomegalovirus (HCMV) infection has been implicated in epithelial ovarian cancer (OC). Polyploidy giant cancer cells (PGCCs) have been observed in high-grade serous ovarian carcinoma (HGSOC); they possess cancer stem cell-like characteristics and give rise to progeny cells expressing epithelial-mesenchymal transition (EMT) markers. EZH2 plays a potential oncogenic role, correlating with high proliferative index and tumor grade in OC. Herein, we present the experimental evidence for HCMV as a reprogramming vector that elicited human ovarian epithelial cells (OECs) transformation leading to the generation of "CMV-transformed Ovarian cells" (CTO). The infection with the two high-risk clinical strains, namely HCMV-DB and BL provoked a distinct cellular and molecular mechanisms in infected OECs. EZH2 upregulation and cellular proliferation were curtailed by using EZH2 inhibitors. The HGSOC biopsies were characterized by an elevated EZH2 expression, possessing a strong positive correlation between the aforementioned marker and HCMV. From HGSOC biopsies, we isolated three HCMV clinical strains that transformed OECs generating CTO cells which displayed proliferative potentials in addition to EZH2 upregulation and PGCCs generation; these features were reduced upon EZH2 inhibition. High-risk HCMV strains transformed OECs confirming an HCMV-induced epithelial ovarian cancer model and highlighting EZH2 tumorigenic properties. Our findings might be highly relevant in the pathophysiology of ovarian tumors thereby nominating new targeted therapeutics.

The role of T cells and myeloid-derived suppressor cells in refractory immune thrombocytopenia

Immune thrombocytopenia (ITP) is characterized by a dysregulated immune response against platelets, affecting both their destruction and production. A role for an abnormal T-cell compartment has been established in ITP pathogenesis and treatments that increase platelet counts in patients with ITP have shown improvements in T-cell profiles. On the other hand, patients who were refractory to treatment appear to retain the T-cell abnormalities as before. Myeloid-derived suppressive cells (MDSCs) are also emerging as key contributors to the immune pathology of ITP and response to treatment. In this review, we will discuss how various treatments affect the T-cell and MDSC compartments in ITP. The review will focus on studies that have examined the underlying mechanisms and/or genetic basis responsible for refractoriness to a given treatment and highlight remaining challenges in identifying factors and mechanisms to predict response to treatment.

Towards single cell encapsulation for precision biology and medicine

The primary impetus of therapeutic cell encapsulation in the past several decades has been to broaden the options for donor cell sources by countering against immune-mediated rejection. However, another significant advantage of encapsulation is to provide donor cells with physiologically relevant cues that become compromised in disease. The advances in biomaterial design have led to the fundamental insight that cells sense and respond to various signals encoded in materials, ranging from biochemical to mechanical cues. The biomaterial design for cell encapsulation is becoming more sophisticated in controlling specific aspects of cellular phenotypes and more precise down to the single cell level. This recent progress offers a paradigm shift by designing single cell-encapsulating materials with predefined cues to precisely control donor cells after transplantation.

Comparative Analysis of Biological Signatures between Freshly Preserved and Cryo-Preserved Bone Marrow Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) can differentiate into multiple connective tissue lineages, including osteoblasts, chondrocytes, and adipocytes. MSCs secrete paracrine molecules that are associated with immunomodulation, anti-fibrotic effects, and angiogenesis. Due to their orchestrative potential, MSCs have been therapeutically applied for several diseases. An important aspect of this process is the delivery of high-quality MSCs to patients at the right time, and cryo-biology and cryo-preservation facilitate the advancement of the logistics thereof. This study aimed to compare the biological signatures between freshly preserved and cryo-preserved MSCs by using big data sourced from the Pharmicell database. From 2011 to 2022, data on approximately 2300 stem cell manufacturing cases were collected. The dataset included approximately 60 variables, including viability, population doubling time (PDT), immunophenotype, and soluble paracrine molecules. In the dataset, 671 cases with no missing data were able to receive approval from an Institutional Review Board and were analyzed. Among the 60 features included in the final dataset, 20 were selected by experts and abstracted into two features by using a principal component analysis. Circular clustering did not introduce any differences between the two MSC preservation methods. This pattern was also observed when using viability, cluster of differentiation (CD) markers, and paracrine molecular indices as inputs for unsupervised analysis. The individual average PDT and cell viability at most passages did not differ according to the preservation method. Most immunophenotypes (except for the CD14 marker) and paracrine molecules did not exhibit different mean levels or concentrations between the frozen and unfrozen MSC groups. Collectively, the biochemical signatures of the cryo-preserved and unfrozen bone marrow MSCs were comparable.

Targeted Delivery of RGD-CD146+CD271+ Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosomes Promotes Blood-Spinal Cord Barrier Repair after Spinal Cord Injury

Spinal cord injury (SCI) disrupts the blood-spinal cord barrier (BSCB), potentially exacerbating nerve damage and emphasizing the criticality of preserving the BSCB integrity during SCI treatment. This study explores an alternative therapeutic approach for SCI by identifying a subpopulation of exosomes with stable BSCB function and achieving a specific targeted delivery. Specific subpopulations of CD146+CD271+ umbilical cord mesenchymal stem cells (UCMSCs) were isolated, from which engineered exosomes (RGD-CD146+CD271+ UCMSC-Exos) with targeted neovascularization function were obtained through gene transfection. In vivo and in vitro experiments were performed to explore the targeting and therapeutic effects of RGD-CD146+CD271+ UCMSC-Exos and the potential mechanisms underlying BSCB stabilization and neural function recovery. The results demonstrated that RGD-CD146+CD271+ UCMSC-Exos exhibited physical and chemical properties similar to those of regular exosomes. Notably, following intranasal administration, RGD-CD146+CD271+ UCMSC-Exos exhibited enhanced aggregation at the SCI center and demonstrated the specific targeting of neovascular endothelial cells. In the SCI model, intranasal administration of RGD-CD146+CD271+ UCMSC-Exos reduced Evans blue dye leakage, increased tight junction protein expression, and improved neurological function recovery. In vitro testing revealed that RGD-CD146+CD271+ UCMSC-Exos treatment significantly reduced the permeability of bEnd.3 cells subjected to oxygen-glucose deprivation, thereby restoring the integrity of tight junctions. Moreover, further exploration of the molecular mechanism underlying BSCB stabilization by CD146+CD271+ UCMSC-Exos identified the crucial role of the miR-501-5p/MLCK axis in this process. In conclusion, targeted delivery of RGD-CD146+CD271+ UCMSC-Exos presents a promising and effective treatment option for SCI.

Application of mesenchymal stem cells for anti-senescence and clinical challenges

Senescence is a hot topic nowadays, which shows the accumulation of senescent cells and inflammatory factors, leading to the occurrence of various senescence-related diseases. Although some methods have been identified to partly delay senescence, such as strengthening exercise, restricting diet, and some drugs, these only slow down the process of senescence and cannot fundamentally delay or even reverse senescence. Stem cell-based therapy is expected to be a potential effective way to alleviate or cure senescence-related disorders in the coming future. Mesenchymal stromal cells (MSCs) are the most widely used cell type in treating various diseases due to their potentials of self-replication and multidirectional differentiation, paracrine action, and immunoregulatory effects. Some biological characteristics of MSCs can be well targeted at the pathological features of aging. Therefore, MSC-based therapy is also a promising strategy to combat senescence-related diseases. Here we review the recent progresses of MSC-based therapies in the research of age-related diseases and the challenges in clinical application, proving further insight and reference for broad application prospects of MSCs in effectively combating senesce in the future.

Revealing the developmental origin and lineage predilection of neural progenitors within human bone marrow via single-cell analysis: implications for regenerative medicine

BACKGROUND

Human bone marrow stromal cells (BMSCs) are an easily accessible and expandable progenitor population with the capacity to generate neural cell types in addition to mesoderm. Lineage tracing studies in transgenic animals have indicated Nestin + BMSCs to be descended from the truncal neural crest. Single-cell analysis provides a means to identify the developmental origin and identity of human BMSC-derived neural progenitors when lineage tracing remains infeasible. This is a prerequisite towards translational application.

METHODS

We attained transcriptomic profiles of embryonic long bone, adult human bone marrow, cultured BMSCs and BMSC-derived neurospheres. Integrated scRNAseq analysis was supplemented by characterization of cells during culture expansion and following provision of growth factors and signalling agonists to bias lineage.

RESULTS

Reconstructed pseudotime upon the integrated dataset indicated distinct neural and osteogenic differentiation trajectories. The starting state towards the neural differentiation trajectory consisted of Nestin + /MKI67 + BMSCs, which could also be diverted towards the osteogenic trajectory via a branch point. Nestin + /PDGFRA + BMSCs responded to neurosphere culture conditions to generate a subpopulation of cells with a neuronal phenotype according to marker expression and gene ontogeny analysis that occupied the end state along the neural differentiation trajectory. Reconstructed pseudotime also revealed an upregulation of BMP4 expression during culture of BMSC-neurospheres. This provided the rationale for culture supplementation with the BMP signalling agonist SB4, which directed progenitors to upregulate Pax6 and downregulate Nestin.

CONCLUSIONS

This study suggested BMSCs originating from truncal neural crest to be the source of cells within long bone marrow possessing neural differentiation potential. Unravelling the transcriptomic dynamics of BMSC-derived neural progenitors promises to enhance differentiation efficiency and safety towards clinical application in cell therapy and disease modelling.

Insights into the tumor-stromal-immune cell metabolism cross talk in ovarian cancer

The ovarian cancer tumor microenvironment (TME) consists of a constellation of abundant cellular components, extracellular matrix, and soluble factors. Soluble factors, such as cytokines, chemokines, structural proteins, extracellular vesicles, and metabolites, are critical means of noncontact cellular communication acting as messengers to convey pro- or antitumorigenic signals. Vast advancements have been made in our understanding of how cancer cells adapt their metabolism to meet environmental demands and utilize these adaptations to promote survival, metastasis, and therapeutic resistance. The stromal TME contribution to this metabolic rewiring has been relatively underexplored, particularly in ovarian cancer. Thus, metabolic activity alterations in the TME hold promise for further study and potential therapeutic exploitation. In this review, we focus on the cellular components of the TME with emphasis on 1) metabolic signatures of ovarian cancer; 2) understanding the stromal cell network and their metabolic cross talk with tumor cells; and 3) how stromal and tumor cell metabolites alter intratumoral immune cell metabolism and function. Together, these elements provide insight into the metabolic influence of the TME and emphasize the importance of understanding how metabolic performance drives cancer progression.

The mTORC1 pathway participate in hyper-function of B cells in immune thrombocytopenia

B cell hyper-function plays an important role in the pathogenesis of immune thrombocytopenia (ITP), but the molecular mechanisms underlying such changes remain unclear. We sought to identify regulators of B cell dysfunction in ITP patients through transcriptome sequencing and the use of inhibitors. B cells were isolated from PBMC of 25 ITP patients for B cell function test and transcriptome sequencing. For the potential regulatory factors identified by transcriptome sequencing, the corresponding protein inhibitors were used to explore the regulatory effect of the regulatory factors on B cell dysfunction in vitro. In this study, increased antibody production, enhanced terminal differentiation and highly expressed costimulatory molecules CD80 and CD86 were found in B cells of patients with ITP. In addition, RNA sequencing revealed highly activated mTOR pathway in these pathogenic B cells, indicating that the mTOR pathway may be involved in B cell hyper-function. Furthermore, mTOR inhibitors rapamycin or Torin1 effectively blocked the activation of mTORC1 in B cells, resulting in reduce antibody secretion, impaired differentiation of B cells into plasmablasts and downregulation of costimulatory molecules. Interestingly, as an unspecific inhibitor of mTORC2 besides mTORC1, Torin1 did not show a stronger capacity to modulate B cell function than rapamycin, suggesting that the regulation of B cells by Torin1 may depend on blockade of mTORC1 rather than mTORC2 pathway. These results indicated that the activation of mTORC1 pathway is involved in B cell dysfunction in patients with ITP, and inhibition of mTORC1 pathway might be a potential therapeutic approach for ITP.

Endogenous PTEN acts as the key determinant for mTOR inhibitor sensitivity by inducing the stress-sensitized PTEN-mediated death axis in KSHV-associated malignant cells

As a part of viral cancer evolution, KSHV-infected human endothelial cells exert a unique transcriptional program via upregulated mTORC1 signaling. This event makes them sensitive to mTOR inhibitors. Master transcriptional regulator PTEN acts as the prime regulator of mTOR and determining factor for mTOR inhibitory drug resistance and sensitivity. PTEN is post-translationally modified in KSHV-associated cell lines and infected tissues. Our current study is an attempt to understand the functional role of upstream modulator PTEN in determining the sensitivity of mTOR inhibitors against KSHV-infected cells in an in vitro stress-responsive model. Our analysis shows that, despite phosphorylation, endogenous levels of intact PTEN in different KSHV-infected cells compared to normal and non-infected cells are quite high. Genetic overexpression of intact PTEN showed functional integrity of this gene in the infected cells in terms of induction of a synchronized cell death process via cell cycle regulation and mitochondria-mediated apoptosis. PTEN overexpression enhanced the mTOR inhibitory drug activity, the silencing of which hampers the process against KSHV-infected cells. Additionally, we have shown that endogenous PTEN acts as a stress balancer molecule inside KSHV-infected cells and can induce stress-sensitized death program post mTOR inhibitor treatment, lined up in the ATM-chk2-p53 axis. Moreover, autophagic regulation was found as a major regulator in mTOR inhibitor-induced PTEN-mediated death axis from our study. The current work critically intersected the PTEN-mediated stress balancing mechanism where autophagy has been utilized as a part of the KSHV stress management system and is specifically fitted and switched toward autophagy-mediated apoptosis directing toward a therapeutic perspective.

Pterostilbene induces apoptosis in hepatocellular carcinoma cells: Biochemical, pathological, and molecular markers

Worldwide, hepatocellular carcinoma (HCC) is considered the sixth most prevalent cancer and ranked third in causes leading to death. Pterostilbene (PTE), a dimethylated analog of resveratrol, is a phytochemical found in fruits such as blueberries and grapes, and is known for its anticancer effect. The current study intended to investigate the effect of PTE on HepG2 cells. Cell viability, colony-forming potential, lipid peroxidation, catalase enzyme (CAT), superoxide dismutase (SOD), and caspase 3 activities, histone release, and expression levels of mTOR, S6K1, p53, and STAT3 proteins were assessed in PTE-treated HepG2 cells. In addition, the cellular and ultrastructural alterations were evaluated by light and transmission electron microscopy. PTE induced a significant reduction in HepG2 viability in a dose-dependent manner (IC₅₀ of PTE = 74 ± 6 μM), accompanied by a decrease in colony formation potential. PTE-treated cancer cells exhibited a decrease in lipid peroxidation and CAT activity, and an increase in histone release, caspase-3, and SOD activities. Ultrastructurally, PTE-treated cells exhibited notable cell shrinkage, reduced number of filopodia, increased vacuolization, apoptotic bodies, accumulation of lipid droplets, enlarged mitochondria, dilated endoplasmic reticulum, pyknotic nuclei, and cellular fragmentation. mTOR, S6K1, and STAT3 levels were downregulated, however p53 level was modulated in PTE-treated cells. The anticancer potential of PTE might be related to its ability to alter the ultrastructure morphology, reduce mitotic activity, and modulate some key protein required for cell proliferation, suggesting its potential to trigger cancer cells towards apoptosis.

Combining thrombopoietin receptor agonists with immunosuppressive drugs in adult patients with multirefractory immune thrombocytopenia, an update on the French experience

Combining drugs could be an effective option for treating multirefractory ITP, that is, patients not responding to rituximab, thrombopoietin receptor agonists (TPO-RA) and splenectomy. We conducted a retrospective, multicenter, observational study including multirefractory ITP patients who received a combination of a TPO-RA and an immunosuppressive drug. We included 39 patients (67% women, median age 59 years [range 21-96]), with a median ITP duration of 57 months [3-393] and a median platelet count at initiation of 10 × 109 /L [1-35]. The combination regimen was given for a median duration of 12 months [1-103] and included eltrombopag (51%) or romiplostim (49%), associated with mycophenolate mofetil (54%), azathioprine (36%), cyclophosphamide (5%), cyclosporin (3%) or everolimus (3%). Overall, 30 patients (77%) achieved at least a response (platelet count ≥30 × 109 /L and at least doubling baseline during at least 3 months), including 24 complete responses (platelet count >100 × 109 /L during at least 3 months) with a median time to response of 30 days [7-270] and a median duration of response of 15 months [4-63]. Severe adverse event related to ITP treatment was observed in 31%. In conclusion, this study confirms that some patients with multirefractory ITP can achieve long lasting response with this combination.

Rituximab resistance in ITP and beyond

The pathophysiology of immune thrombocytopenia (ITP) is complex and encompasses innate and adaptive immune responses, as well as megakaryocyte dysfunction. Rituximab is administered in relapsed cases and has the added benefit of inducing treatment-free remission in over 50% of patients. Nevertheless, the responses to this therapy are not long-lasting, and resistance development is frequent. B cells, T cells, and plasma cells play a role in developing resistance. To overcome this resistance, targeting these pathways through splenectomy and novel therapies that target FcγR pathway, FcRn, complement, B cells, plasma cells, and T cells can be useful. This review will summarize the pathogenetic mechanisms implicated in rituximab resistance and examine the potential therapeutic interventions to overcome it. This review will explore the efficacy of established therapies, as well as novel therapeutic approaches and agents currently in development.

Multi-omics analysis of human mesenchymal stem cells shows cell aging that alters immunomodulatory activity through the downregulation of PD-L1

Mesenchymal stem cells (MSCs) possess potent immunomodulatory activity and have been extensively investigated for their therapeutic potential in treating inflammatory disorders. However, the mechanisms underlying the immunosuppressive function of MSCs are not fully understood, hindering the development of standardized MSC-based therapies for clinical use. In this study, we profile the single-cell transcriptomes of MSCs isolated from adipose tissue (AD), bone marrow (BM), placental chorionic membrane (PM), and umbilical cord (UC). Our results demonstrate that MSCs undergo a progressive aging process and that the cellular senescence state influences their immunosuppressive activity by downregulating PD-L1 expression. Through integrated analysis of single-cell transcriptomic and proteomic data, we identify GATA2 as a regulator of MSC senescence and PD-L1 expression. Overall, our findings highlight the roles of cell aging and PD-L1 expression in modulating the immunosuppressive efficacy of MSCs and implicating perinatal MSC therapy for clinical applications in inflammatory disorders.

BCR-ABL1-driven exosome-miR130b-3p-mediated gap-junction Cx43 MSC intercellular communications imply therapies of leukemic subclonal evolution

Rationale: In the bone marrow microenvironment (BMME), mesenchymal stem/stromal cells (MSCs) control the self-renewal of both healthy and cancerous hematopoietic stem/progenitor cells (HSPCs). We previously showed that in vivo leukemia-derived MSCs change neighbor MSCs into leukemia-permissive states and boost leukemia cell proliferation, survival, and chemotherapy resistance. But the mechanisms behind how the state changes are still not fully understood. Methods: Here, we took a reverse engineering approach to determine BCR-ABL1+ leukemia cells activated transcriptional factor C/EBPβ, resulting in miR130a/b-3p production. Then, we back-tracked from clinical specimen transcriptome sequencing to cell co-culture, molecular and cellular assays, flow cytometry, single-cell transcriptome, and transcriptional regulation to determine the molecular mechanisms of BCR-ABL1-driven exosome-miR130b-3p-mediated gap-junction Cx43 MSC intercellular communications. Results: BCR-ABL1-driven exosome-miR130a/b-3p mediated gap-junction Cx43 (a.k.a., GJA1) BMSC intercellular communications for subclonal evolution in leukemic microenvironment by targeting BMSCs-expressed HLAs, thereby potentially maintaining BMSCs with self-renewal properties and reduced BMSC immunogenicity. The Cx43low and miR-130a/bhigh subclonal MSCs subsets of differentiation state could be reversed to Cx43high and miR-130a/blow subclones of the higher stemness state in Cx43-overexpressed subclonal MSCs. Both miR-130a and miR-130b might only inhibit Cx43 translation or degrade Cx43 proteins and did not affect Cx43 mRNA stability. The subclonal evolution was further confirmed by single-cell transcriptome profiling of MSCs, which suggested that Cx43 regulated their stemness and played normal roles in immunomodulation antigen processing. Thus, upregulated miR-130a/b promoted osteogenesis and adipogenesis from BMSCs, thereby decreasing cancer progression. Our clinical data validated that the expression of many genes in human major histocompatibility was negatively associated with the stemness of MSCs, and several immune checkpoint proteins contributing to immune escape in tumors were overexpressed after either miR-130a or miR-130b overexpression, such as CD274, LAG3, PDCD1, and TNFRSF4. Not only did immune response-related cytokine-cytokine receptor interactions and PI3K-AKT pathways, including EGR3, TNFRSF1B, but also NDRG2 leukemic-associated inflammatory factors, such as IFNB1, CXCL1, CXCL10, and CCL7 manifest upon miR-130a/b overexpression. Either BCR siRNAs or ABL1 siRNAs assay showed significantly decreased miR-130a and miR-130b expression, and chromatin immunoprecipitation sequencing confirmed that the regulation of miR-130a and miR-130b expression is BCR-ABL1-dependent. BCR-ABL1 induces miR-130a/b expression through the upregulation of transcriptional factor C/EBPβ. C/EBPβ could bind directly to the promoter region of miR-130b-3p, not miR-130a-3p. BCR-ABL1-driven exosome-miR130a-3p could interact with Cx43, and further impact GJIC in TME. Conclusion: Our findings shed light on how leukemia BCR-ABL1-driven exosome-miR130b-3p could interact with gap-junction Cx43, and further impact GJIC in TME, implications for leukemic therapies of subclonal evolution.

Integration of Transcriptome and MicroRNA Profile Analysis of iMSCs Defines Their Rejuvenated State and Conveys Them into a Novel Resource for Cell Therapy in Osteoarthritis

Although MSCs grant pronounced potential for cell therapies, several factors, such as their heterogeneity restrict their use. To overcome these limitations, iMSCs (MSCs derived from induced pluripotent stem cells (iPSCs) have attracted attention. Here, we analyzed the transcriptome of MSCs, iPSCs and iMSCs derived from healthy individuals and osteoarthritis (OA) patients and explored miRNA-mRNA interactions during these transitions. We performed RNA-seq and gene expression comparisons and Protein-Protein-Interaction analysis followed by GO enrichment and KEGG pathway analyses. MicroRNAs' (miRNA) expression profile using miRarrays and differentially expressed miRNA's impact on regulating iMSCs gene expression was also explored. Our analyses revealed that iMSCs derivation from iPSCs favors the expression of genes conferring high proliferation, differentiation, and migration properties, all of which contribute to a rejuvenated state of iMSCs compared to primary MSCs. Additionally, our exploration of the involvement of miRNAs in this rejuvenated iMSCs transcriptome concluded in twenty-six miRNAs that, as our analysis showed, are implicated in pluripotency. Notably, the identified here interactions between hsa-let7b/i, hsa-miR-221/222-3p, hsa-miR-302c, hsa-miR-181a, hsa-miR-331 with target genes HMGA2, IGF2BP3, STARD4, and APOL6 could prove to be the necessary tools that will convey iMSCs into the ideal mean for cell therapy in osteoarthritis.

Real-life use of mTOR inhibitor-based therapy in adults with autoimmune cytopenia highlights strong efficacy in relapsing/refractory multi-lineage autoimmune cytopenia

Data on mTOR inhibitors (mTORi) in autoimmune cytopenia (AIC), in adults are scarce. We retrospectively analysed 30 cases of refractory or relapsing AIC treated with an mTORi-based therapy. Eleven warm autoimmune hemolytic anaemia, 10 autoimmune thrombocytopenia, 6 acquired pure red cell aplasia, 3 autoimmune neutropenia were included. Twenty were multilineage AIC (67%) and 21 were secondary AIC (70%). mTORi were associated with other therapies in 23 AIC (77%). Twenty-two AIC (73%) responded to mTORi-based therapy: 5 reached a partial response (17%) and 17 a complete response (57%). Survival without unfavourable outcome (failure, requirement of a new therapy, or death) was longer in multilineage AIC compared to single-lineage AIC (p = 0.049) with a median event-free survival of 48 versus 12 months. Median event-free survival was 48 months in secondary AIC and 33 months in primary AIC (p = 0.79). mTORi were discontinued in 4 patients (15%) for safety reasons and in 3 patients for patient's choice (12%). In conclusion, mTORi could be considered as an alternative or an add-on therapy in refractory or relapsing AIC in adult patients, especially in multilineage AIC.

Current Understanding on Why Ovarian Cancer Is Resistant to Immune Checkpoint Inhibitors

The standard treatment of ovarian cancer (OC) patients, including debulking surgery and first-line chemotherapy, is unsatisfactory because of recurrent episodes in the majority (~70%) of patients with advanced OC. Clinical trials have shown only a modest (10-15%) response of OC individuals to treatment based on immune checkpoint inhibitors (ICIs). The resistance of OC to therapy is caused by various factors, including OC heterogeneity, low density of tumor-infiltrating lymphocytes (TILs), non-cellular and cellular interactions in the tumor microenvironment (TME), as well as a network of microRNA regulating immune checkpoint pathways. Moreover, ICIs are the most efficient in tumors that are marked by high microsatellite instability and high tumor mutation burden, which is rare among OC patients. The great challenge in ICI implementation is connected with distinguishing hyper-, pseudo-, and real progression of the disease. The understanding of the immunological, molecular, and genetic mechanisms of OC resistance is crucial to selecting the group of OC individuals in whom personalized treatment would be beneficial. In this review, we summarize current knowledge about the selected factors inducing OC resistance and discuss the future directions of ICI-based immunotherapy development for OC patients.

Delayed spontaneous remission of acquired factor V inhibitor refractory to immunosuppressive therapy with pregnancy-associated improvement

Introduction: Acquired factor V inhibitor (AFVI) is a rare autoimmune bleeding disorder. The treatment of AFVI is challenging, and patients often require both bleeding control and inhibitor eradication. Methods: We conducted a retrospective analysis of the medical records of a 35-year-old Caucasian woman who presented with severe AFVI-induced bleeding and subsequent immunosuppressive therapy. Results: To provide haemostasis, rFVIIa was given with good efficacy. The patient was treated with various combinations of immunosuppressive regimens over the course of 2.5 years, including plasmapheresis plus immunoglobulins, dexamethasone + rituximab, cyclophosphamide + dexamethasone + rituximab + cyclosporine, cyclosporin + sirolimus + cyclophosphamide + dexamethasone, bortezomib + sirolimus + methylprednisolone, and sirolimus + mycophenolate mofetil. Although these treatment modalities resulted in intermittent partial reversals of AFVI over 2.5 years, eventually the inhibitor became therapy-resistant. However, following the discontinuation of all immunosuppressive therapy, the patient experienced a partial spontaneous remission, which was followed by a pregnancy. During the pregnancy, the FV activity increased to 54% and the coagulation parameters returned to normal levels. The patient underwent Caesarean section without any bleeding complications and delivered a healthy child. Discussion: The use of an activated bypassing agent for bleeding control is effective in patients with severe AFVI. The presented case is unique because the treatment regimens included multiple combinations of immunosuppressive agents. This demonstrates that AFVI patients may undergo spontaneous remission even after multiple courses of ineffective immunosuppressive protocols. Additionally, pregnancy-associated improvement of AFVI is an important finding that warrants further investigation.