Dataset Information

Hemoglobin alpha-like chain subunit mu (HBM) is expressed during ontogeny and is elevated in alpha thalassemias

ABSTRACT: Background: Alpha and beta-like globin chains are encoded by gene clusters on chromosomes 16 and 11, respectively, with controlled expression patterns through development and childhood into adulthood. The alpha gene cluster contains genes such as HBA1, HBA2, HBZ and HBM. HBM was initially thought to be a pseudogene. Subsequently, although a transcript was reported in cord blood, the encoded protein was not detected by early mass spectrometry-based analyses. Methods: Dried blood spots (DBS) were obtained from umbilical cord blood of neonates born at term as well as preterm neonates born at different gestational age. DBS were also prepared from peripheral venous blood from other pediatric subjects up to 5 years of age. We developed a targeted mass spectrometry assay for all alpha- and beta-like globin chains using heavy synthetic peptide standards which were unique to each chain. Proteins were extracted from DBS samples and digested. The resulting samples were cleaned-up and spiked-in with heavy synthetic peptide standards prior to analysis in liquid chromatography – multiple reaction monitoring (LC-MRM) mode. Additionally, samples from patients with alpha thalassemia and from unaffected adult donors were also analyzed. Results: Analysis of dried blood spots (DBS) from neonates by LC-MS/MS using discovery proteomics pipelines resulted in detection of HBM protein along with other globin chains with multiple unique peptides each. Targeted selected reaction monitoring (SRM) assays resulted in the detection of HBM in samples from preterm newborns at higher levels compared to all other samples. As the gestational age at collection increased from 32 weeks to term, the levels of HBM decreased, continuing to do so with postnatal age. Importantly, HBM levels fell precipitously between one week and two years after birth. Interestingly, HBM protein was detected at quantifiable levels in all tested samples including adult blood samples. The levels of HBM were elevated in certain types of alpha thalassemia in comparison with unaffected adult donors. Conclusions: Our data reveal that HBM gene encodes a protein that is expressed at low levels in adults but is more abundant during development, suggesting that it could play a role in ontogeny, which is likely taken over by other globin chains post-birth. Further experimental studies are required to fully understand the functional role of HBM and its potential beta-like globin binding partner. The elevated levels of HBM observed in patients with alpha thalassemia are likely a compensatory mechanism to offset the deficiency of alpha-like chains.

INSTRUMENT(S):

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Blood Cell, Blood

DISEASE(S): Disease Free,Alpha Thalassemia

SUBMITTER: Akhilesh Pandey

LAB HEAD: Akhilesh Pandey, M.D., Ph.D.

PROVIDER: PXD064022 | Pride | 2026-04-27

REPOSITORIES: Pride

ACCESS DATA

Dataset's files

Source:

			Action	DRS
	010424_Hbpathies_Mu_CalCurve_100fmol_R01.raw	Raw
	010424_Hbpathies_Mu_CalCurve_100fmol_R02.raw	Raw
	010424_Hbpathies_Mu_CalCurve_100fmol_R03.raw	Raw
	010424_Hbpathies_Mu_CalCurve_1fmol_R01.raw	Raw
	010424_Hbpathies_Mu_CalCurve_1fmol_R02.raw	Raw

Items per page:

1 - 5 of 89

Publications

Hemoglobin alpha-like subunit mu is expressed during ontogeny and is elevated in alpha thalassemia.

Garapati Kishore K Chavan Sandip S Bellad Anikha A Venkataraman Shilpa S Oglesbee Devin D Chakraborty Rana R Wick Myra J MJ Girard Sylvie S Pandey Akhilesh A

Blood. Red cells & iron 20260203 1

The alpha globin gene cluster on chromosome 16 encodes alpha-like globins whose expression changes during development. <i>HBM</i> located in this cluster was considered a pseudogene until its transcript was discovered in 2005, but without a detectable protein product. Here, we provide the first detailed description of <i>HBM</i>-encoded globin at the protein level (hemoglobin mu chain [HBM]) across different age groups using liquid chromatography coupled with tandem mass spectrometry. Using targ ...[more]

PMID: 42004318

Similar Datasets

Project description:Background: The thalassemias are highly diverse at both the molecular and clinical levels. Many of the HBB mutations that result in β-thalassemia are missense mutations in the coding region of the β-globin gene, but a few cause alternative splicing, and interfere with normal processing of the β-globin transcripts. Transcriptome profiling in individuals affected with β-thalassemia, especially in individuals who carry novel mutations in the HBB, may improve our understanding of the heterogeneity and molecular mechanisms of the disease. Methods: Members of a family with a daughter affected with thalassemia intermedia, although her mother was not clinically affected, were examined for physical characteristics, hematological parameters and β-globin gene sequences. We also characterized genome-wide gene expression in the family using RT-qPCR and high-throughput RNA-sequencing mRNA expression profiling of blood. Results: Clinical findings, hematological indices, DNA and RNA sequence analysis of individuals with β-thalassemia, including the description of a novel mutation in the β-globin gene, which introduces a cryptic donor splice site. More than 300 genes are differentially expressed in β-thalassemic blood with many of the DEGs involved in pathways relevant to the clinical management of β-thalassemia. β-thalassemia shows important similarities and differences with sickle cell disease at the transcriptome level. Conclusions: We described the down-regulation of the β-globin gene in β-thalassemia by RNA-sequencing analysis using a sample from an affected individual and her mother, who have a novel mutation in the HBB that creates a cryptic donor splice site. The daughter has a typical β-thalassemia allele as well, and an unexpectedly severe phenotype. The DEGs are enriched in pathways that are directly or indirectly related to β-thalassemia such as hemopoiesis, heme biosynthesis, response to oxidative stress, inflammatory responses, immune responses, control of circadian rhythm, apoptosis, and other cellular activities. We compare our findings with published results of RNA-Sequencing analysis of sickle cell disease (SCD) and erythroblasts from a KLF1-null neonate with hydrops fetalis, and recognize similarities and differences in their transcriptional expression patterns.