Targeting a thrombopoietin-independent strategy in the discovery of a novel inducer of megakaryocytopoiesis, DMAG, for the treatment of thrombocytopenia

Multimodal discovery of bavachinin A: A natural FLT3 agonist for treating thrombocytopenia

BACKGROUND

Radiation-induced thrombocytopenia (RIT) poses a serious risk to patients with cancer undergoing radiotherapy and leads to hemorrhage and mortality. Unfortunately, effective treatment options for RIT are currently limited.

PURPOSE

This study aimed to discover active compound from Fructus Psoraleae, a traditional Chinese medicine recognized for its hemostatic properties, and to elucidate its mechanism of action in the treatment of RIT.

METHODS

The efficacy of Fructus Psoraleae in treating thrombocytopenia was assessed using network pharmacology. A drug-screening model was built using a naive Bayes algorithm to determine the effective compounds in Fructus Psoraleae. Giemsa staining and flow cytometry were used to evaluate the effects of bavachinin A on megakaryocytes (MK) differentiation. RIT and thrombopoietin (TPO) receptor (c-MPL) knockout (c-MPL-/-) mice were used to assess the therapeutic efficacy of bavachinin A in mitigating thrombocytopenia. Tg (cd41:eGFP) zebrafish were used to investigate the effect of bavachinin A on thrombopoiesis. RNA sequencing (RNA-seq), molecular docking simulations, molecular dynamics simulations, drug affinity responsive target stability assay (DARTS), and biolayer interferometry (BLI) were used to elucidate the molecular mechanisms of action of bavachinin A against thrombocytopenia.

RESULTS

In silico analysis using a drug screening model identified bavachinin A as promising candidate compound derived from Fructus Psoraleae. In vitro experiments demonstrated that Bavachinin A induced MK differentiation. In vivo experiments revealed that bavachinin A augmented platelet levels and improved coagulation in RIT mice, facilitated megakaryopoiesis and platelet levels in c-MPL-/- mice, and accelerated thrombopoiesis in zebrafish. Furthermore, RNA-seq, molecular docking simulations, molecular dynamics simulations, DARTS, and BLI demonstrated that bavachinin A bound directly to fms-like tyrosine kinase 3 (FLT3). Notably, blocking FLT3 or phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway hindered bavachinin-A-induced MK differentiation. However, repressing the TPO/c-MPL signaling pathway had no significant effect.

CONCLUSION

Bavachinin A promotes MK differentiation and thrombopoiesis by directly binding to FLT3 and activating PI3K/Akt signaling. Importantly, this effect was not dependent on the conventional TPO/c-MPL signaling pathway. This study underscores the translational potential of bavachinin A as a promising novel therapeutic for thrombocytopenia, offering novel insights into TPO-independent mechanisms of thrombopoiesis and establishing a robust multimodal approach for drug discovery.

Therapeutic potential of roxadustat in immune thrombocytopenia: a Mendelian randomization analysis

BACKGROUND

Immune thrombocytopenia (ITP) is characterized by immune-mediated platelet destruction and impaired megakaryocyte maturation. Hypoxia-inducible factor-1α (HIF-1α), pivotal in the development of megakaryocytes and immune regulation, is downregulated in ITP. Roxadustat, which stabilizes HIF-1α, has emerged as a potential therapeutic drug for ITP that acts by enhancing HIF-1α-mediated megakaryocyte development and modulating immune responses.

OBJECTIVES

This study evaluates the safety profile of roxadustat and its therapeutic efficacy for ITP treatment using Mendelian randomization (MR) analysis.

METHODS

We used expression quantitative trait loci data for roxadustat's target genes (EGLN1, EGLN2, and EGLN3) and genetic associations with ITP and adverse outcomes from the Open Genome-Wide Association Study project. MR analysis included inverse-variance weighted, MR-Egger regression, weighted median, and MR pleiotropy residual sum and outlier methods to evaluate pleiotropy. Heterogeneity was assessed using Cochran's Q statistic and I2 measure with sensitivity analyses. A meta-analysis was performed to integrate effect sizes from multiple literature sources.

RESULTS

MR analysis revealed a significant association between roxadustat and reduced ITP risk (odds ratio, 0.79; 95% CI, 0.66-0.95; P = .01) with no evidence of horizontal pleiotropy. Meta-analysis confirmed the protective effect of roxadustat on ITP. Utilizing the expression quantitative trait loci of roxadustat's target gene EGLN1 as instrumental variables, an MR analysis of 39 potential adverse reactions revealed no significant increase, suggesting a favorable safety profile for roxadustat.

CONCLUSION

Roxadustat demonstrates a potential protective effect against ITP without increasing the risk of adverse outcomes, suggesting its promise as a therapeutic option for ITP and warranting further investigation.

Sheng Xue Ning as a Novel Agent that Promotes SCF-Driven Hematopoietic Stem/Progenitor Cell Proliferation to Promote Erythropoiesis

Stimulating erythropoiesis is essential in the treatment of various types of anemia. Sheng Xue Ning (SXN) is commonly used in China as an iron supplement to treat iron deficiency anemia, renal anemia, and anemia in pregnancy. This research reports a novel effect of SXN in enhancing the proliferation of hematopoietic stem/progenitor cell (HSPC) to promote erythropoiesis in the bone marrow, which is distinct from conventional iron supplements that primarily aid in the maturation of red blood cells. Employing a model of hematopoietic dysfunction induced by X-ray exposure, we evaluated the efficacy of SXN in restoring hematopoietic function. SXN significantly promoted the recovery of peripheral erythroid cells and enhanced the proliferation and differentiation of Lin-/c-KIT+/Sca-1+ HSPC in mice exposed to X-ray irradiation. Our results showed that SXN elevated the expression of stem cell factor (SCF) and activated the SCF/c-KIT/PI3K/AKT signaling pathway, facilitating the proliferation and differentiation of HSPC. In vitro, SXN markedly enhanced the proliferation of bone marrow nucleated cell (BMNC) and the colony-forming capacity of BFU-E, CFU-E, and CFU-GM, while also elevating the expression of proteins involved in the SCF/c-KIT/PI3K/AKT pathway in BMNC. Additionally, SXN enhanced the proliferation and differentiation of mesenchymal stem cell (MSC) and increased SCF secretion. In conclusion, SXN demonstrates the capacity to enhance erythropoiesis by upregulating SCF expression, thereby promoting HSPC proliferation and differentiation via the SCF/c-KIT/PI3K/AKT pathway. SXN may offer a new strategy for improving the activity of HSPC and promoting erythropoiesis in the treatment of hematopoiesis disorders.

Identification of Active Molecules against Thrombocytopenia through Machine Learning

Thrombocytopenia, which is associated with thrombopoietin (TPO) deficiency, presents very limited treatment options and can lead to life-threatening complications. Discovering new therapeutic agents against thrombocytopenia has proven to be a challenging task using traditional screening approaches. Fortunately, machine learning (ML) techniques offer a rapid avenue for exploring chemical space, thereby increasing the likelihood of uncovering new drug candidates. In this study, we focused on computational modeling for drug-induced megakaryocyte differentiation and platelet production using ML methods, aiming to gain insights into the structural characteristics of hematopoietic activity. We developed 112 different classifiers by combining eight ML algorithms with 14 molecule features. The top-performing model achieved good results on both 5-fold cross-validation (with an accuracy of 81.6% and MCC value of 0.589) and external validation (with an accuracy of 83.1% and MCC value of 0.642). Additionally, by leveraging the Shapley additive explanations method, the best model provided quantitative assessments of molecular properties and structures that significantly contributed to the predictions. Furthermore, we employed an ensemble strategy to integrate predictions from multiple models and performed in silico predictions for new molecules with potential activity against thrombocytopenia, sourced from traditional Chinese medicine and the Drug Repurposing Hub. The findings of this study could offer valuable insights into the structural characteristics and computational prediction of thrombopoiesis inducers.

Activating SRC/MAPK signaling via 5-HT1A receptor contributes to the effect of vilazodone on improving thrombocytopenia

Thrombocytopenia caused by long-term radiotherapy and chemotherapy exists in cancer treatment. Previous research demonstrates that 5-Hydroxtrayptamine (5-HT) and its receptors induce the formation of megakaryocytes (MKs) and platelets. However, the relationships between 5-HT1A receptor (5-HTR1A) and MKs is unclear so far. We screened and investigated the mechanism of vilazodone as a 5-HTR1A partial agonist in promoting MK differentiation and evaluated its therapeutic effect in thrombocytopenia. We employed a drug screening model based on machine learning (ML) to screen the megakaryocytopoiesis activity of Vilazodone (VLZ). The effects of VLZ on megakaryocytopoiesis were verified in HEL and Meg-01 cells. Tg (itga2b: eGFP) zebrafish was performed to analyze the alterations in thrombopoiesis. Moreover, we established a thrombocytopenia mice model to investigate how VLZ administration accelerates platelet recovery and function. We carried out network pharmacology, Western blot, and immunofluorescence to demonstrate the potential targets and pathway of VLZ. VLZ has been predicted to have a potential biological action. Meanwhile, VLZ administration promotes MK differentiation and thrombopoiesis in cells and zebrafish models. Progressive experiments showed that VLZ has a potential therapeutic effect on radiation-induced thrombocytopenia in vivo. The network pharmacology and associated mechanism study indicated that SRC and MAPK signaling are both involved in the processes of megakaryopoiesis facilitated by VLZ. Furthermore, the expression of 5-HTR1A during megakaryocyte differentiation is closely related to the activation of SRC and MAPK. Our findings demonstrated that the expression of 5-HTR1A on MK, VLZ could bind to the 5-HTR1A receptor and further regulate the SRC/MAPK signaling pathway to facilitate megakaryocyte differentiation and platelet production, which provides new insights into the alternative therapeutic options for thrombocytopenia.

Genistin: A Novel Estrogen Analogue Targeting ERβ to Alleviate Thrombocytopenia

Thrombocytopenia, a prevalent hematologic challenge, correlates directly with the mortality of numerous ailments. Current therapeutic avenues for thrombocytopenia are not without limitations. Here, we identify genistin, an estrogen analogue, as a promising candidate for thrombocytopenia intervention, discovered through AI-driven compound library screening. While estrogen's involvement in diverse biological processes is recognized, its role in thrombopoiesis remains underexplored. Our findings elucidate genistin's ability to enhance megakaryocyte differentiation, thereby augmenting platelet formation and production. In vivo assessments further underscore genistin's remedial potential against radiation-induced thrombocytopenia. Mechanistically, genistin's efficacy is attributed to its direct interaction with estrogen receptor β (ERβ), with subsequent activation of both ERK1/2 and the Akt signaling pathways membrane ERβ. Collectively, our study positions genistin as a prospective therapeutic strategy for thrombocytopenia, shedding light on novel interplays between platelet production and ERβ.

Targeting CD38/ ADP-ribosyl cyclase as a novel therapeutic strategy for identification of three potent agonists for leukopenia treatment

Leukopenia is the most common side effect of chemotherapy and radiotherapy. It potentially deteriorates into a life-threatening complication in cancer patients. Despite several agents being approved for clinical administration, there are still high incidences of pathogen-related disease due to a lack of functional immune cells. ADP-ribosyl cyclase of CD38 displays a regulatory effect on leukopoiesis and the immune system. To explore whether the ADP-ribosyl cyclase was a potential therapeutic target of leukopenia. We established a drug screening model based on an ADP-ribosyl cyclase-based pharmacophore generation algorithm and discovered three novel ADP-ribosyl cyclase agonists: ziyuglycoside II (ZGSII), brevifolincarboxylic acid (BA), and 3,4-dihydroxy-5-methoxybenzoic acid (DMA). Then, in vitro experiments demonstrated that these three natural compounds significantly promoted myeloid differentiation and antibacterial activity in NB4 cells. In vivo, experiments confirmed that the compounds also stimulated the recovery of leukocytes in irradiation-induced mice and zebrafish. The mechanism was investigated by network pharmacology, and the top 12 biological processes and the top 20 signaling pathways were obtained by intersecting target genes among ZGSII, BA, DMA, and leukopenia. The potential signaling molecules involved were further explored through experiments. Finally, the ADP-ribosyl cyclase agonists (ZGSII, BA, and DMA) has been found to regenerate microbicidal myeloid cells to effectively ameliorate leukopenia-associated infection by activating CD38/ADP-ribosyl cyclase-Ca2+-NFAT. In summary, this study constructs a drug screening model to discover active compounds against leukopenia, reveals the critical roles of ADP-ribosyl cyclase in promoting myeloid differentiation and the immune response, and provides a promising strategy for the treatment of radiation-induced leukopenia.