Computational and physicochemical insight into 4-hydroxy-2-nonenal induced structural and functional perturbations in human low-density lipoprotein

Abstract

Lipid peroxidation (LPO) is a biological process that frequently occurs under physiological conditions. Undue oxidative stress increases the level of LPO; which may further contribute to the development of cancer. 4-Hydroxy-2-nonenal (HNE), one of the principal by-products of LPO, is present in high concentrations in oxidatively stressed cells. HNE rapidly reacts with various biological components, including DNA and proteins; however, the extent of protein degradation by lipid electrophiles is not well understood. The influence of HNE on protein structures will likely have a considerable therapeutic value. This research elucidates the potential of HNE, one of the most researched phospholipid peroxidation products, in modifying low-density lipoprotein (LDL). In this study, we tracked the structural alterations in LDL by HNE using various physicochemical techniques. To comprehend the stability, binding mechanism and conformational dynamics of the HNE-LDL complex, computational investigations were carried out. LDL was altered in vitro by HNE, and the secondary and tertiary structural alterations were examined using spectroscopic methods, such as UV–visible, fluorescence, circular dichroism and fourier transform infrared spectroscopy. Carbonyl content, thiobarbituric acid-reactive-substance (TBARS) and nitroblue tetrazolium (NBT) reduction assays were used to examine changes in the oxidation status of LDL. Thioflavin T (ThT), 1-anilinonaphthalene-8-sulfonic (ANS) binding assay and electron microscopy were used to investigate aggregates formation. According to our research, LDL modified by HNE results in changes in structural dynamics, oxidative stress and the formation of LDL aggregates. The current investigation must characterize HNE's interactions with LDL and comprehend how it can change their physiological or pathological functions.

Communicated by Ramaswamy H. Sarma

Keywords:

• Low-density lipoprotein
• 4-hydroxy-2-nonenal
• lipid peroxidation
• oxidative stress
• aggregation
• reactive oxygen species

Acknowledgments

Authors are thankful to Department of Biochemistry, J.N. Medical College for providing research facilities, Infrastructure facilities provided by the Department of Science & Technology under DST-FIST program, University Sophisticated Instrumentation (USIF), Aligarh Muslim University, for electron microscopy and BRAF at C-DAC, Pune, for providing a supercomputer facility to perform Molecular dynamics simulation analysis. We also thank Mohammad Danish Khan (Loughborough University, United Kingdom) for his support during writing, review and editing.N.T. receives the fellowship from the university grants commission.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.

CrediT authorship contribution statement

Neda Tufail: Conceptualization, Data curation, Formal analysis, Investigation, Methodology, Writing – original draft.

Minhal Abidi: Methodology and Validation

Mohd. Sharib Warsi: Review and Editing

Tasneem Kausar: Software, Visualization.

Shahid M. Nayeem: Software, Visualization.

Moinuddin: Supervision, Conceptualization, Validation, Resources and Writing – review and editing.