Omics Studies in Hemoglobinopathies

Potential Use of MicroRNA Technology in Thalassemia Therapy

Thalassemia encompasses a group of inherited hemoglobin disorders characterized by reduced or absent production of the α- or β-globin chains, leading to anemia and other complications. Current management relies on lifelong blood transfusions and iron chelation, which is burdensome for patients. This review summarizes the emerging therapeutic potential of modulating microRNAs (miRNAs) to treat thalassemia. MiRNAs are small non-coding RNAs that regulate gene expression through sequence-specific binding to messenger RNAs (mRNAs). While they commonly repress gene expression by binding to the 3' untranslated regions (UTRs) of target mRNAs, miRNAs can also interact with 5'UTRs and gene promoters to activate gene expression. Many miRNAs are now recognized as critical regulators of erythropoiesis and are abnormally expressed in β-thalassemia. Therapeutically restoring levels of deficient miRNAs or inhibiting overexpression through miRNA mimics or inhibitors (antagomir), respectively, has shown preclinical efficacy in ameliorating thalassemic phenotypes. The miR-144/451 cluster is especially compelling for targeted upregulation to reactivate fetal hemoglobin synthesis. Advances in delivery systems are addressing previous challenges in stability and targeting of miRNA-based drugs. While still early, gene therapy studies suggest combinatorial approaches with miRNA modulation may provide synergistic benefits. Several key considerations remain including enhancing delivery, minimizing off-target effects, and demonstrating long-term safety and efficacy. While no miRNA therapies have yet progressed to clinical testing for thalassemia specifically, important lessons are being learned through clinical trials for other diseases and conditions, such as cancer, cardiovascular diseases, and viral. If limitations can be overcome through multi-disciplinary collaboration, miRNAs hold great promise to expand and transform treatment options for thalassemia in the future by precisely targeting pathogenic molecular networks. Ongoing innovations, such as advancements in miRNA delivery systems, improved targeting mechanisms, and enhanced understanding of miRNA biology, continue to drive progress in this emerging field towards realizing the clinical potential of miRNA-based medicines for thalassemia patients.

A Novel Hemoglobin Variant Hb Liaobu [α107(G14)Val→Leu, HBA2: c.322G>C] Detected by Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry

We here describe a novel hemoglobin (Hb) variant, Hb Liaobu [α107(G14)Val→Leu, HBA2: c.322G>C], in a Chinese family. The structurally abnormal α chain variant could not be detected using capillary electrophoresis (CE) and was subsequently characterized by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS), and further confirmed by reversed phase high performance liquid chromatography (HPLC). Sanger sequencing revealed a novel base mutation on the α2-globin gene and RNA analysis by reverse transcription polymerase chain reaction (RT-PCR) showed the presence of an abnormal HBA transcript. The isopropanol stability test indicated the stable state of this structural Hb variant. In conclusion, a new Hb variant, Hb Liaobu, was discovered and characterized. It was proven to be a nonpathogenic variant. Our study resolved the confusion in the clinical diagnosis of individuals with this novel Hb variant in this family.

Amniotic fluid metabolomic and lipidomic alterations associated with hemoglobin Bart's diseases

INTRODUCTION

α-Thalassemia is the most common inherited disease in southern China. The severest form is hemoglobin (Hb) Bart's disease, in which the affected fetuses almost always die in utero or shortly after birth, and the mothers are at high risk for severe morbidity.

OBJECTIVE

To investigate the changes in all metabolites in fetuses with Hb Bart's disease and to characterize the metabolomic and lipidomic biomarkers in the development of Hb Bart's fetuses.

METHODS

Amniotic fluid (AF) specimens were selected from 34 pregnant women who underwent interventional prenatal diagnosis from June 2017 to June 2018. Gap-PCR analysis was used to diagnose Hb Bart's disease, and untargeted metabolomic and lipidomic analyses were performed.

RESULTS

By analyzing AF samples, 935 differential metabolites were selected between Hb Bart's and control fetuses. The metabolites with significant changes mainly involved D-glutamine and D-glutamate metabolism, histidine metabolism, arginine metabolism, beta-alanine metabolism and alanine, aspartate and glutamate metabolism. Further lipidomics analysis revealed 132 differential lipids, mainly involved phosphatidylcholine and triglyceride metabolism. Through the characterized metabolites in AF, a schematic model of Hb Bart's disease was established.

CONCLUSION

Glutamate and glutathione metabolism, aspartate metabolism, urea metabolism and triglyceride metabolism were significantly changed in the Hb Bart's group compared to the control group. The characterized biomarkers were mainly involved in oxidative stress reaction, iron overload and liver dysfunction. This finding may help improve the treatment options for α-thalassemia as well as diagnosing phenotype of patients.

Genome-based therapeutic interventions for β-type hemoglobinopathies

For decades, various strategies have been proposed to solve the enigma of hemoglobinopathies, especially severe cases. However, most of them seem to be lagging in terms of effectiveness and safety. So far, the most prevalent and promising treatment options for patients with β-types hemoglobinopathies, among others, predominantly include drug treatment and gene therapy. Despite the significant improvements of such interventions to the patient's quality of life, a variable response has been demonstrated among different groups of patients and populations. This is essentially due to the complexity of the disease and other genetic factors. In recent years, a more in-depth understanding of the molecular basis of the β-type hemoglobinopathies has led to significant upgrades to the current technologies, as well as the addition of new ones attempting to elucidate these barriers. Therefore, the purpose of this article is to shed light on pharmacogenomics, gene addition, and genome editing technologies, and consequently, their potential use as direct and indirect genome-based interventions, in different strategies, referring to drug and gene therapy. Furthermore, all the latest progress, updates, and scientific achievements for patients with β-type hemoglobinopathies will be described in detail.

Integration of organ metabolomics and proteomics in exploring the blood enriching mechanism of Danggui Buxue Decoction in hemorrhagic anemia rats

ETHNOPHARMACOLOGICAL RELEVANCE

Danggui Buxue Decoction (DBD), as a classical Chinese medicine prescription, is composed of Danggui (DG) and Huangqi (HQ) at a ratio of 1:5, and it has been used clinically in treating anemia for hundreds of years.

AIM OF THE STUDY

The aim of this study was to explore the treatment mechanisms of DBD in anemia rats from the perspective of thymus and spleen.

MATERIALS AND METHODS

In this study, a successful hemorrhagic anemia model was established, and metabolomics (UPLC-QTOF-MS/MS) and proteomics (label-free approach) together with bioinformatics (Gene Ontology analysis and Reactome pathway enrichment), correlation analysis (pearson correlation matrix) and joint pathway analysis (MetaboAnalyst) were employed to discover the underlying mechanisms of DBD.

RESULTS

DBD had a significant blood enrichment effect on hemorrhagic anemia rats. Metabolomics and proteomics results showed that DBD regulated a total of 10 metabolites (lysophosphatidylcholines, etc.) and 41 proteins (myeloperoxidase, etc.) in thymus, and 9 metabolites (L-methionine, etc.) and 24 proteins (transferrin, etc.) in spleen. With GO analysis and Reactome pathway enrichment, DBD mainly improved anti-oxidative stress ability of thymocyte and accelerated oxidative phosphorylation to provide ATP for splenocyte. Phenotype key indexes were strongly and positively associated with most of the differential proteins and metabolites, especially nucleosides, amino acids, Fabp4, Decr1 and Ndufs3. 14 pathways in thymus and 9 pathways in spleen were obtained through joint pathway analysis, in addition, the most influential pathway in thymus was arachidonic acid metabolism, while in spleen was the biosynthesis of phenylalanine, tyrosine and tryptophan. Furthermore, DBD was validated to up-regulate Mpo, Hbb and Cp levels and down-regulate Ca²⁺ level in thymus, as well as up-regulate Fabp4, Ndufs3, Tf, Decr1 and ATP levels in spleen.

CONCLUSION

DBD might enhance thymus function mainly by reducing excessive lipid metabolism and intracellular Ca²⁺ level, and promote ATP production in spleen to provide energy.