MMP9 inhibition increases erythropoiesis in RPS14-deficient del(5q) MDS models through suppression of TGF-β pathways

Study on diagnostic-sensitive markers of primary immune thrombocytopenia in children based on plasma proteomics

To use proteomic techniques to identify sensitive diagnostic biomarkers for paediatric immune thrombocytopenia (ITP). We selected children in ITP and control groups, using a four-dimensional data-independent acquisition approach (4D-DIA) to analyse its protein expression. The significantly differentially expressed proteins were selected for enzyme-linked immunosorbent assay (ELISA) validation in a cohort comprising 50 samples (13 healthy controls, 15 secondary thrombocytopenia controls and 22 children with ITP). Receiver operating characteristics (ROC) were generated to diagnose ITP and to assess the diagnostic effectiveness of this approach. Compared with the control group, 55 differentially expressed proteins (43 increased and 12 decreased) were determined in the ITP group. Matrix metalloproteinases-9 (MMP-9) and thrombospondin-1 (THBS1) were significantly expressed and selected for ELISA. The verification outcomes aligned with the findings from the proteomic examinations. In contrast to the control cohort, the ITP subjects exhibited markedly elevated plasma MMP-9 levels and reduced plasma THBS1 concentrations. Additionally, the ROC curves indicated the diagnostic value of these biomarkers. In conclusion, proteomics facilitates identifying the sensitive biomarkers for ITP diagnosis. We have preliminarily selected two differentially expressed proteins, MMP-9 and THBS1, whose potential role as biomarkers for diagnosing ITP requires further research.

Single-cell transcriptional profile of CD34+ hematopoietic progenitor cells from del(5q) myelodysplastic syndromes and impact of lenalidomide

While myelodysplastic syndromes with del(5q) (del(5q) MDS) comprises a well-defined hematological subgroup, the molecular basis underlying its origin remains unknown. Using single cell RNA-seq (scRNA-seq) on CD34+ progenitors from del(5q) MDS patients, we have identified cells harboring the deletion, characterizing the transcriptional impact of this genetic insult on disease pathogenesis and treatment response. Interestingly, both del(5q) and non-del(5q) cells present similar transcriptional lesions, indicating that all cells, and not only those harboring the deletion, may contribute to aberrant hematopoietic differentiation. However, gene regulatory network (GRN) analyses reveal a group of regulons showing aberrant activity that could trigger altered hematopoiesis exclusively in del(5q) cells, pointing to a more prominent role of these cells in disease phenotype. In del(5q) MDS patients achieving hematological response upon lenalidomide treatment, the drug reverts several transcriptional alterations in both del(5q) and non-del(5q) cells, but other lesions remain, which may be responsible for potential future relapses. Moreover, lack of hematological response is associated with the inability of lenalidomide to reverse transcriptional alterations. Collectively, this study reveals transcriptional alterations that could contribute to the pathogenesis and treatment response of del(5q) MDS.

TGF-β2 Induces Ribosome Activity, Alters Ribosome Composition and Inhibits IRES-Mediated Translation in Chondrocytes

Alterations in cell fate are often attributed to (epigenetic) regulation of gene expression. An emerging paradigm focuses on specialized ribosomes within a cell. However, little evidence exists for the dynamic regulation of ribosome composition and function. Here, we stimulated a chondrocytic cell line with transforming growth factor beta (TGF-β2) and mapped changes in ribosome function, composition and ribosomal RNA (rRNA) epitranscriptomics. 35S Met/Cys incorporation was used to evaluate ribosome activity. Dual luciferase reporter assays were used to assess ribosomal modus. Ribosomal RNA expression and processing were determined by RT-qPCR, while RiboMethSeq and HydraPsiSeq were used to determine rRNA modification profiles. Label-free protein quantification of total cell lysates, isolated ribosomes and secreted proteins was done by LC-MS/MS. A three-day TGF-β2 stimulation induced total protein synthesis in SW1353 chondrocytic cells and human articular chondrocytes. Specifically, TGF-β2 induced cap-mediated protein synthesis, while IRES-mediated translation was not (P53 IRES) or little affected (CrPv IGR and HCV IRES). Three rRNA post-transcriptional modifications (PTMs) were affected by TGF-β2 stimulation (18S-Gm1447 downregulated, 18S-ψ1177 and 28S-ψ4598 upregulated). Proteomic analysis of isolated ribosomes revealed increased interaction with eIF2 and tRNA ligases and decreased association of eIF4A3 and heterogeneous nuclear ribonucleoprotein (HNRNP)s. In addition, thirteen core ribosomal proteins were more present in ribosomes from TGF-β2 stimulated cells, albeit with a modest fold change. A prolonged stimulation of chondrocytic cells with TGF-β2 induced ribosome activity and changed the mode of translation. These functional changes could be coupled to alterations in accessory proteins in the ribosomal proteome.

Increased Levels of BAMBI Inhibit Canonical TGF-β Signaling in Chronic Wound Tissues

Chronic wounds affect more than 2% of the population worldwide, with a significant burden on affected individuals, healthcare systems, and societies. A key regulator of the entire wound healing cascade is transforming growth factor beta (TGF-β), which regulates not only inflammation and extracellular matrix formation but also revascularization. This present work aimed at characterizing wound tissues obtained from acute and chronic wounds regarding angiogenesis, inflammation, as well as ECM formation and degradation, to identify common disturbances in the healing process. Serum and wound tissues from 38 patients (N = 20 acute and N = 18 chronic wounds) were analyzed. The patients' sera suggested a shift from VEGF/VEGFR to ANGPT/TIE2 signaling in the chronic wounds. However, this shift was not confirmed in the wound tissues. Instead, the chronic wound tissues showed increased levels of MMP9, a known activator of TGF-β. However, regulation of TGF-β target genes, such as CTGF, COL1A1, or IL-6, was absent in the chronic wounds. In wound tissues, all three TGF-β isoforms were expressed with increased levels of TGF-β1 and TGF-β3 and a reporter assay confirmed that the expressed TGF-β was activated. However, Western blots and immunostaining showed decreased canonical TGF-β signaling in the respective chronic wound tissues, suggesting the presence of a TGF-β inhibitor. As a potential regulatory mechanism, the TGF-β proteome profiler array suggested elevated levels of the TGF-β pseudo-receptor BAMBI. Also, tissue expression of BAMBI was significantly increased not only in chronic wounds (10.6-fold) but also in acute wounds that had become chronic (9.5-fold). In summary, our data indicate a possible regulatory role of BAMBI in the development of chronic wounds. The available few in vivo studies support our findings by postulating a therapeutic potential of BAMBI for controlling scar formation.

Immunohistochemical Features of MMP-9 and pSTAT1 in Granuloma Annulare and Sarcoidosis: A Comparative Study of 62 Cases

Background

Granuloma annulare (GA) and sarcoidosis are granulomatous inflammatory diseases that share similarities.

Objective

To identify the histological and immunohistochemical (IHC) features of GA and sarcoidosis.

Methods

A retrospective review of 36 patients with GA and 26 with sarcoidosis was performed. Results from hematoxylin and eosin (H&E) staining and IHC staining of MMP-9 and pSTAT1 within the skin lesions of GA and sarcoidosis were analyzed, and random forest was applied for developing a predictive model.

Results

Significantly greater expressions of MMP-9 (especially in elastic fibers, EFs, P < 0.0001) and pSTAT1 (P = 0.0003) were observed in lesion samples of GA versus sarcoidosis patients. In GA patients, MMP-9 was significantly upregulated in the interstitial type (P = 0.0222), while staining of pSTAT1 was positively correlated with the area of mucinous collagen in palisading GA (R = 0.5356, P = 0.0484). In sarcoidosis patients, MMP-9 (R = -0.7127, P = 0.0009) and pSTAT1 (R = -0.5604, P = 0.0067) were found to show stronger expressions in lesions with less lymphocyte infiltration. The predictive model demonstrated an AUC of 0.9675.

Conclusion

These results indicate that MMP-9 and pSTAT1 might exert roles in granulomatous inflammation in different modes, and the presence of more robust MMP-9 staining in EFs appears to be more suggestive of GA.

The yin-yang of immunity: Immune dysregulation in myelodysplastic syndrome with different risk stratification

Myelodysplastic syndrome (MDS) is a heterogeneous group of myeloid clonal diseases with diverse clinical courses, and immune dysregulation plays an important role in the pathogenesis of MDS. However, immune dysregulation is complex and heterogeneous in the development of MDS. Lower-risk MDS (LR-MDS) is mainly characterized by immune hyperfunction and increased apoptosis, and the immunosuppressive therapy shows a good response. Instead, higher-risk MDS (HR-MDS) is characterized by immune suppression and immune escape, and the immune activation therapy may improve the survival of HR-MDS. Furthermore, the immune dysregulation of some MDS changes dynamically which is characterized by the coexistence and mutual transformation of immune hyperfunction and immune suppression. Taken together, the authors think that the immune dysregulation in MDS with different risk stratification can be summarized by an advanced philosophical thought “Yin-Yang theory” in ancient China, meaning that the opposing forces may actually be interdependent and interconvertible. Clarifying the mechanism of immune dysregulation in MDS with different risk stratification can provide the new basis for diagnosis and clinical treatment. This review focuses on the manifestations and roles of immune dysregulation in the different risk MDS, and summarizes the latest progress of immunotherapy in MDS.

Establishment of an In Vitro Scab Model for Investigating Different Phases of Wound Healing

Chronic wounds are a serious problem in clinical work and a heavy burden for individuals and society. In order to develop novel therapies, adequate model systems for the investigation of wound healing are required. Although in past years different in vitro and in vitro wound healing models have been established, a true human-like model does still not exist. Animal models are limited in their use due to species-specific differences in the skin, a lengthy manufacturing process, experimental costs, and ethical concerns. Both 2D and 3D in vitro models are usually comprised of only one or two skin cell types and fail to capture the reaction between blood cells and skin cells. Thus, our aim was to develop an in vitro scab model to investigate early reactions in the wound healing process. The here established scab model is comprised of HaCaT cells and freshly collected blood from healthy volunteers. The generated scabs were stably cultured for more than 2 weeks. TGF-β signaling is well known to regulate the early phases of wound healing. All three TGF-β isoforms and target genes involved in extracellular matrix composition and degradation were expressed in the in vitro scabs. To validate the in vitro scab model, the effects of either additional stimulation or the inhibition of the TGF-β signaling pathway were investigated. Exogenous application of TGF-β1 stimulated matrix remodeling, which loosened the structure of the in vitro scabs with time, also induced expression of the inhibitory Smad7. Inhibition of the endogenous TGF-β signaling, on the contrary, resulted in a rapid condensation and degranulation of the in vitro scabs. In summary, the here established in vitro scab model can be used to analyze the first phases of wound healing where blood and skin cells interact, as it is viable and responsive for more than 2 weeks.

Cell autonomous and non-autonomous consequences of deviations in translation machinery on organism growth and the connecting signalling pathways

Translation machinery is responsible for the production of cellular proteins; thus, cells devote the majority of their resources to ribosome biogenesis and protein synthesis. Single-copy loss of function in the translation machinery components results in rare ribosomopathy disorders, such as Diamond-Blackfan anaemia in humans and similar developmental defects in various model organisms. Somatic copy number alterations of translation machinery components are also observed in specific tumours. The organism-wide response to haploinsufficient loss-of-function mutations in ribosomal proteins or translation machinery components is complex: variations in translation machinery lead to reduced ribosome biogenesis, protein translation and altered protein homeostasis and cellular signalling pathways. Cells are affected both autonomously and non-autonomously by changes in translation machinery or ribosome biogenesis through cell-cell interactions and secreted hormones. We first briefly introduce the model organisms where mutants or knockdowns of protein synthesis and ribosome biogenesis are characterized. Next, we specifically describe observations in Caenorhabditis elegans and Drosophila melanogaster, where insufficient protein synthesis in a subset of cells triggers cell non-autonomous growth or apoptosis responses that affect nearby cells and tissues. We then cover the characterized signalling pathways that interact with ribosome biogenesis/protein synthesis machinery with an emphasis on their respective functions during organism development.

Immune Dysfunction, Cytokine Disruption, and Stromal Changes in Myelodysplastic Syndrome: A Review

Myelodysplastic syndromes (MDS) are myeloid neoplasms characterized by bone marrow dysfunction and increased risk of transformation to leukemia. MDS represent complex and diverse diseases that evolve from malignant hematopoietic stem cells and involve not only the proliferation of malignant cells but also the dysfunction of normal bone marrow. Specifically, the marrow microenvironment-both hematopoietic and stromal components-is disrupted in MDS. While microenvironmental disruption has been described in human MDS and murine models of the disease, only a few current treatments target the microenvironment, including the immune system. In this review, we will examine current evidence supporting three key interdependent pillars of microenvironmental alteration in MDS-immune dysfunction, cytokine skewing, and stromal changes. Understanding the molecular changes seen in these diseases has been, and will continue to be, foundational to developing effective novel treatments that prevent disease progression and transformation to leukemia.

Using the Zebrafish as a Genetic Model to Study Erythropoiesis

Vertebrates generate mature red blood cells (RBCs) via a highly regulated, multistep process called erythropoiesis. Erythropoiesis involves synthesis of heme and hemoglobin, clearance of the nuclei and other organelles, and remodeling of the plasma membrane, and these processes are exquisitely coordinated by specific regulatory factors including transcriptional factors and signaling molecules. Defects in erythropoiesis can lead to blood disorders such as congenital dyserythropoietic anemias, Diamond–Blackfan anemias, sideroblastic anemias, myelodysplastic syndrome, and porphyria. The molecular mechanisms of erythropoiesis are highly conserved between fish and mammals, and the zebrafish (Danio rerio) has provided a powerful genetic model for studying erythropoiesis. Studies in zebrafish have yielded important insights into RBC development and established a number of models for human blood diseases. Here, we focus on latest discoveries of the molecular processes and mechanisms regulating zebrafish erythropoiesis and summarize newly established zebrafish models of human anemias.

Expression profile analysis reveals hub genes that are associated with immune system dysregulation in primary myelofibrosis

OBJECTION

Primary myelofibrosis (PMF) is a familiar chronic myeloproliferative disease with an unfavorable prognosis. The effect of infection on the prognosis of patients with PMF is crucial. Immune system dysregulation plays a central role in the pathophysiology of PMF. To date, very little research has been conducted on the molecular mechanism of immune compromise in patients with PMF.

METHODS

To explore potential candidate genes, microarray datasets GSE61629 and 26049 were obtained from the Gene Expression Omnibus (GEO) database. The differentially expressed genes (DEGs) between PMF patients and normal individuals were evaluated, gene function was measured and a series of hub genes were identified. Several significant immune cells were selected via cell type enrichment analysis. The correlation between hub genes and significant immune cells was determined.

RESULTS

A total of 282 DEGs were found, involving 217 upregulated genes and 65 downregulated genes. Several immune cells were found to be reduced in PMF, such as CD4⁺ T cells, CD4⁺ Tems, CD4⁺ memory T cells. Gene Ontology (GO) enrichment analysis of DEGs reflected that most biological processes were associated with immune processes. Six hub genes, namely, HP, MPO, MMP9, EPB42, SLC4A1, and ALAS2, were identified, and correlation analysis revealed that these hub genes have a negative correlation with immune cell abundance.

CONCLUSIONS

Taken together, the gene expression profile of whole blood cells in PMF patients indicated a battery of immune events, and the DEGs and hub genes might contribute to immune system dysregulation.

The Dynamic Interface Between the Bone Marrow Vascular Niche and Hematopoietic Stem Cells in Myeloid Malignancy

Hematopoietic stem cells interact with bone marrow niches, including highly specialized blood vessels. Recent studies have revealed the phenotypic and functional heterogeneity of bone marrow endothelial cells. This has facilitated the analysis of the vascular microenvironment in steady state and malignant hematopoiesis. In this review, we provide an overview of the bone marrow microenvironment, focusing on refined analyses of the marrow vascular compartment performed in mouse studies. We also discuss the emerging role of the vascular niche in “inflamm-aging” and clonal hematopoiesis, and how the endothelial microenvironment influences, supports and interacts with hematopoietic cells in acute myeloid leukemia and myelodysplastic syndromes, as exemplar states of malignant myelopoiesis. Finally, we provide an overview of strategies for modulating these bidirectional interactions to therapeutic effect in myeloid malignancies.

Sex Effect on Cardiac Damage in Mice With Experimental Autoimmune Encephalomyelitis

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system. Recent clinical study suggested that MS patient exhibited acute heart failure. Further, 12-lead electrocardiographic study showed a longer QTc interval in both MS patient and experimental autoimmune encephalomyelitis (EAE) Lewis rat. However, there is limited study regarding the effect of sex on cardiac injury in EAE. To our knowledge, sex effect on cardiac damage in mice with EAE has not yet been published. Herein, we examined the role of the immune system in mediating cardiac dysfunction after EAE in female and male mice. Neurological function was subsequently evaluated and cardiac function was assessed by echocardiography at multiple time points after EAE. EAE mice exhibited severe neurological deficit and significant cardiac dysfunction, including decreased left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) at 1 and 2 months after EAE induction. Meanwhile male EAE presented increased expression of the oxidative stress (e.g., nicotinamaide adenine dinucleotide phosphate oxidase-2; NOX-2) in heart, as well as cardiac hypertrophy, increased left ventricle (LV) mass and more severe cardiac fibrosis compared with male control mice. In addition, male EAE mice showed significantly increased cardiac canonical inflammatory mediator (e.g., monocyte chemoattractant protein-1; MCP-1, transforming growth factor-β; TGF-β and toll-like receptor 2; TLR-2) compared with female EAE mice at 2 months after EAE induction. In conclusion, EAE increases inflammatory factor expression and aggravates cardiac dysfunction in male mice compared with female mice, which may contribute to different cardiac outcome in EAE mice.

Loss of 5q in myeloid malignancies - A gain in understanding of biological and clinical consequences

Hemizygous interstitial or terminal deletion of the long arm of chromosome 5 [del(5q)] is a recurrent cytogenetic abnormality in myeloid malignancies, including myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). These deletions cause loss of a large contiguous chromosomal region encompassing more than 30 genes, which results in disease through haploinsufficiency of one or more genes including RPS14. In MDS, del(5q) in isolation is a lower-risk cytogenetic anomaly and is sometimes associated with a unique clinicopathological phenotype, but in AML it represents a higher-risk lesion, often denoting secondary AML arising from prior MDS. Lenalidomide effectively targets the del(5q)-bearing clone in MDS, resulting in sustained erythroid transfusion independence in most patients and cytogenetic remission in a subset of treated patients. Since the initial regulatory approval of lenalidomide for del(5q) MDS in 2005, translational research endeavors in del(5q)-associated myeloid malignancies have improved our understanding of how allelic haploinsufficiency underlies both the hematological phenotype and selective sensitivity to lenalidomide therapy. This review will focus on the molecular pathogenesis of del(5q) in myeloid malignancies, clinical development of lenalidomide and emerging data on lenalidomide-refractory del (5q) MDS, and possible novel targeted therapeutic strategies.