bims-meglyc 2025-01-05 papers

Issue of 2025–01–05
four papers selected by
Silvia Radenkovic, UMC Utrecht

Biotechnol Bioeng. 2024 Dec 30.

A Novel, Site-Specific N-Linked Glycosylation Model Provides Mechanistic Insights Into the Process-Condition Dependent Distinct Fab and Fc Glycosylation of an IgG1 Monoclonal Antibody Produced by CHO VRC01 Cells.

Jayanth Venkatarama Reddy, Thomas Leibiger, Sumit Kumar Singh, Kelvin H Lee, Eleftherios Papoutsakis, Marianthi Ierapetritou.

The CHO VRC01 cell line produces an anti-HIV IgG1 monoclonal antibody containing N-linked glycans on both the Fab (variable) and Fc (constant) regions. Site-specific glycan analysis was used to measure the complex effects of cell culture process conditions on Fab and Fc glycosylation. Experimental data revealed major differences in glycan fractions across the two sites. Bioreactor pH was found to influence fucosylation, galactosylation, and sialylation in the Fab region and galactosylation in the Fc region. To understand the complex effects of process conditions on site-specific N-linked glycosylation, a kinetic model of site-specific N-linked glycosylation was developed. The model parameters provided mechanistic insights into the differences in glycan fractions observed in the Fc and Fab regions. Enzyme activities calculated from the model provided insights into the effect of bioreactor pH on site-specific N-linked glycosylation. Model predictions were experimentally tested by measuring glycosyltransferase-enzyme mRNA-levels and intracellular nucleotide sugar concentrations. The model was used to demonstrate the effect of increasing galactosyltransferase activity on site-specific N-linked glycan fractions. Experiments involving galactose and MnCl2 supplementation were used to test model predictions. The model is capable of providing insights into experimentally measured data and also of making predictions that can be used to design media supplementation strategies.

Keywords: Fab glycosylation; critical process parameters; critical quality attributes; glycosylation model; site‐specific N‐linked glycosylation

DOI: https://doi.org/10.1002/bit.28916

J Diabetes Metab Disord. 2025 Jun;24(1): 27

The role of the analysis of sialotransferrin isoforms in the management of hereditary fructose intolerance: a systematic review.

Evelina Maines, Giorgia Gugelmo, Arianna Maiorana, Diego Martinelli, Nicola Vitturi, Livia Lenzini, Giovanni Piccoli, Massimo Soffiati, Roberto Franceschi.

Background: Untreated patients affected by hereditary fructose intolerance (HFI) present an abnormal transferrin (Tf) glycosylation pattern suggestive of N-hypoglycosylation. Analysis of defects in N-glycosylation is possible by analysis of serum sialotransferrin (sialoTf) pattern. The sialoTf profile is a valuable tool to facilitate the diagnosis of HFI. Its role in the monitoring of the diagnosed patients is less clear and debating.
Objectives and methods: We examined the literature for the role of profile of serum sialoTf isoforms in monitoring HFI patients aiming at (1) providing an up-to-date summary of the available evidences on the impact of sialoTf isoforms in the follow-up of HFI patients; 2) evaluating the multifactorial effect of genotype and age at diagnosis on sialoTf isoforms; 3) assessing the relation between sialoTf isoforms and long-term liver complications. We used the GRADE approach to rank the quality of evidence.
Results: Nine full papers were identified according to our search criteria. Elevated serum carbohydrate-deficient Tf (CDT) fraction, disialoTf and tetrasialoTf/disialoTf ratio, and the asialoTf, tetrasialoTf and pentasialoTf + hexasialoTf isoforms appeared as the most reliable indicators for a follow up. No clear statistical correlation links sialoTf isoforms and liver damage. Age at diagnosis, potentially related to fructose tolerance, does not overtly impact sialoTf isoforms. Strong genotype-phenotype correlation has not been found so far.
Conclusions: There is no consensus about which isoform of sialoTf is more valuable for monitoring HFI patients. No clear correlation links sialoTf isoforms and liver damage, fructose tolerance and genotype. More robust studies are needed to provide conclusive results.

Keywords: Follow up; Hereditary fructose intolerance; Sialotransferrin; Systematic review

DOI: https://doi.org/10.1007/s40200-024-01527-y

Mol Genet Metab. 2024 Dec 24. pii: S1096-7192(24)00888-6. [Epub ahead of print]144(1): 109004

Atypical free sialic acid storage disorder associated with tissue specific mosaicism of SLC17A5.

Undiagnosed Diseases Network

Free sialic acid storage disorder (FSASD) is a rare autosomal recessive lysosomal storage disease caused by pathogenic SLC17A5 variants with variable disease severity. We performed a multidisciplinary evaluation of an adolescent female with suspected lysosomal storage disease and conducted comprehensive studies to uncover the molecular etiology. The proband exhibited intellectual disability, a storage disease gestalt, and mildly elevated urine free sialic acid levels. Skin electron micrographs showed prominent cytoplasmic vacuolation. Clinical exome and genome sequencing identified a maternally-inherited SLC17A5 variant: c.533delC;p.Thr178Asnfs*34. RNASeq of proband skin fibroblasts revealed exon 3 skipping, which was not detected in RNA from proband blood or parental fibroblasts. Targeted deep sequencing of proband fibroblast DNA revealed a 184 bp deletion in ∼15 % of reads, encompassing the 3' end of exon 3. Illumina Complete Long Read sequencing confirmed the deletion was in the paternally-inherited allele and found in a mosaic state in proband fibroblasts and muscle but not in blood or buccal cells. Functional studies, including SLC17A5 knockout cells and transient transfections of mutated SLC17A5 demonstrated pathogenicity of the identified variants. We report an adolescent female with atypical FSASD with tissue-specific mosaicism for an intragenic deletion in SLC17A5, explaining the atypical clinical course, mild biochemical abnormalities, and long diagnostic process.

Keywords: Atypical molecular genetics; Deep sequencing; Lysosomal storage; Undiagnosed disease

DOI: https://doi.org/10.1016/j.ymgme.2024.109004

World J Cardiol. 2024 Dec 26. 16(12): 689-706

Molecular and metabolic landscape of adenosine triphosphate-induced cell death in cardiovascular disease.

Wei Wang, Xue-Mei Wang, Hao-Long Zhang, Rui Zhao, Yong Wang, Hao-Ling Zhang, Zhi-Jing Song.

The maintenance of intracellular and extracellular adenosine triphosphate (ATP) levels plays a pivotal role in cardiac function. In recent years, burgeoning attention has been directed towards ATP-induced cell death (AICD), revealing it as a distinct cellular demise pathway triggered by heightened extracellular ATP concentrations, distinguishing it from other forms of cell death such as apoptosis and necrosis. AICD is increasingly acknowledged as a critical mechanism mediating the pathogenesis and progression of various cardiovascular maladies, encompassing myocardial ischemia-reperfusion injury, sepsis-induced cardiomyopathy, hypertrophic cardiomyopathy, arrhythmia, and diabetic cardiomyopathy. Consequently, a comprehensive understanding of the molecular and metabolic underpinnings of AICD in cardiac tissue holds promise for the prevention and amelioration of cardiovascular diseases. This review first elucidates the vital physiological roles of ATP in the cardiovascular system, subsequently delving into the intricate molecular mechanisms and metabolic signatures governing AICD. Furthermore, it addresses the potential therapeutic targets implicated in mitigating AICD for treating cardiovascular diseases, while also delineating the current constraints and future avenues for these innovative therapeutic targets, thereby furnishing novel insights and strategies for the prevention and management of cardiovascular disorders.

Keywords: Adenosine triphosphate induced cell death; Cardiovascular diseases; Metabolic pathways; Molecular mechanisms; Myocardial ischemia-reperfusion injury

DOI: https://doi.org/10.4330/wjc.v16.i12.689