A view of the genetic and proteomic profile of extracellular matrix molecules in aging and stroke

Frontiers in Cellular Neuroscience · 8 authors, 3 centres

AI SUMMARY

FIDELITY 100%

POPULATIONYoung adult (3-month-old) and aged (18-month-old) female C57Black/6 mice

INTERVENTIONPermanent middle cerebral artery occlusion (pMCAo) to model ischemic stroke

COMPARISONAge-matched non-ischemic controls; young vs. aged post-ischemic mice

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TL;DR

This study re-analyzed RNA-Seq and proteomic data from young adult (3-month-old) and aged (18-month-old) mice after permanent middle cerebral artery occlusion to examine age-related changes in extracellular matrix (ECM) gene and protein expression. The results show that aging shifts the balance of ECM regulation toward degradation, with increased expression of matrix metalloproteinases and decreased expression of protective ECM components like brevican and Hapln4. These findings suggest that age-related ECM alterations contribute to the increased sensitivity of aged brain tissue to ischemic injury.

Full summary

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**Background:** Ischemic stroke incidence and mortality increase with age, yet most experimental studies use young animals. Aging alters brain extracellular matrix (ECM) properties, which may affect stroke pathophysiology. The ECM comprises core molecules (e.g., perineuronal nets, basal membrane) and modifying enzymes (MMPs, ADAMTS, TIMPs). This study aimed to identify age-related ECM changes that could explain increased ischemic sensitivity in aged brain.

**Methods:** The authors re-analyzed a previously published RNA-Seq dataset (Androvic et al., 2020) from the parietal cortex of young adult (3-month-old, 3M) and aged (18-month-old, 18M) female C57Black/6 mice, either non-ischemic controls or 3 days after permanent middle cerebral artery occlusion (pMCAo). A targeted set of 56 ECM-related genes was selected. Differential expression was analyzed using DESeq2 (padj < 0.05, log2FC > 1 for upregulation, < -0.65 for downregulation). Proteomic analysis (LC-MS/MS) was performed on separate cohorts at 3 and 7 days post-pMCAo, detecting 18 proteins from the gene set. Statistical comparisons used two-way ANOVA with Tukey post-hoc tests.

**Key Results:** - **Aging alone:** Only 4 of 56 genes differed significantly between 3M and 18M controls: *Hapln2* (padj = 6.29E-09), *Sdc4* (padj = 0.001), *Mmp12* (padj = 0.005) upregulated; *Ncan* (padj = 0.005) downregulated. - **Stroke vs. age-matched controls:** In 3M mice, 39 genes were differentially expressed; in 18M mice, 40 genes. Most were upregulated. Only 6 genes were downregulated: *Bcan* (3M padj = 0.02; 18M padj = 3.3E-06), *Mmp24* (3M padj = 0.007), *Ncan* (3M padj = 0.008), *Sparcl1* (3M padj = 0.0008; 18M padj = 6.78E-08), *Adamts17* (18M padj = 0.0026), *Hapln4* (18M padj = 8.25E-07). Upregulated genes included multiple MMPs (e.g., *Mmp3*, *Mmp9*, *Mmp13*), all four TIMPs (*Timp1* most pronounced: 3M padj = 5.84E-25; 18M padj = 4.99E-30), ADAMTS family members (*Adamts1*, *4*, *5*, *7*, *9*, *14*), syndecans (*Sdc1*, *Sdc3*, *Sdc4*), and other ECM genes (*Fn1*, *Vcan*, *Hapln2*, *Hapln3*, *Tnc*, *Cspg4*, *Ecm1*, *Hspg2*, *Lum*, *Mgp*). - **Stroke: young vs. aged:** Nine genes showed significantly different expression between 3M and 18M post-ischemic mice: *Bcan* downregulated in aged (padj = 0.018); eight upregulated in aged: *Adamts1* (padj = 0.0031), *Ecm1* (padj = 0.047), *Hapln2* (padj = 6.59E-06), *Hpse* (padj = 0.0026), *Lum* (padj = 0.03), *Mgp* (padj = 0.01), *Mmp13* (padj = 0.008), *Sdc3* (padj = 0.0009). - **Proteomic findings:** Only 18 proteins were detected. Significant changes were found in Hapln2 (upregulated in aged controls, padj = 7.80E-03; and more elevated in aged vs. young post-ischemic at D3 and D7, both padj < 0.0001), fibronectin (Fn1; upregulated in both ages post-stroke at D3 and D7, padj < 0.0001; higher in aged vs. young at D3, padj = 0.0214), and vitronectin (Vtn; upregulated in aged at D3, padj < 0.0001; in young at D7, padj = 1.90E-03). In aged post-ischemic mice, Fn1 and Vtn expression dropped significantly from D3 to D7 (Fn1 padj < 0.0001; Vtn padj = 0.0205).

**Clinical Implications:** The study demonstrates that aging shifts the ECM balance toward degradation, with increased expression of proteases (MMPs, ADAMTS) and decreased expression of protective ECM components (brevican, Hapln4). This imbalance likely contributes to the greater ischemic damage and worse outcomes observed in elderly stroke patients. The identification of nine genes and two proteins (Hapln2, Fn1) with age-specific post-stroke expression changes provides potential targets for future therapeutic interventions aimed at modulating ECM remodeling to improve recovery in aged individuals. Limitations include the use of only female mice, a single time point for gene analysis (D3), and limited proteomic detection due to standard tissue processing.

PICO

PPOPULATION

Young adult (3-month-old) and aged (18-month-old) female C57Black/6 mice

IINTERVENTION

Permanent middle cerebral artery occlusion (pMCAo) to model ischemic stroke

OOUTCOME

Differential expression of 56 ECM-related genes (mRNA) and 18 ECM-related proteins; focus on degradation vs. protection balance

STUDY TYPE

other

SPECIALTY

neurology

SUMMARISED BY

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FIDELITY CHECK

100% · A

ORIGINAL PAPER

PMC10723838

A view of the genetic and proteomic profile of extracellular matrix molecules in aging and stroke

Frontiers in Cellular Neuroscience

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ABSTRACT

Abstract Introduction Modification of the extracellular matrix (ECM) is one of the major processes in the pathology of brain damage following an ischemic stroke. However, our understanding of how age-related ECM alterations may affect stroke pathophysiology and its outcome is still very limited. Methods We conducted an ECM-targeted re-analysis of our previously obtained RNA-Seq dataset of aging, ischemic stroke and their interactions in young adult (3-month-old) and aged (18-month-old) mice. The permanent middle cerebral artery occlusion (pMCAo) in rodents was used as a model of ischemic stroke. Altogether 56 genes of interest were chosen for this study. Results We identified an increased activation of the genes encoding proteins related to ECM degradation, such as matrix metalloproteinases (MMPs), proteases of a disintegrin and metalloproteinase with the thrombospondin motifs (ADAMTS) family and molecules that regulate their activity, tissue inhibitors of metalloproteinases (TIMPs). Moreover, significant upregulation was also detected in the mRNA of other ECM molecules, such as proteoglycans, syndecans and link proteins. Notably, we identified 8 genes where this upregulation was enhanced in aged mice in comparison with the young ones. Ischemia evoked a significant downregulation in only 6 of our genes of interest, including those encoding proteins associated with the protective function of ECM molecules (e.g., brevican, Hapln4, Sparcl1); downregulation in brevican was more prominent in aged mice. The study was expanded by proteome analysis, where we observed an ischemia-induced overexpression in three proteins, which are associated with neuroinflammation (fibronectin and vitronectin) and neurodegeneration (link protein Hapln2). In fibronectin and Hapln2, this overexpression was more pronounced in aged post-ischemic animals. Conclusion Based on these results, we can conclude that the ratio between the protecting and degrading mechanisms in the aged brain is shifted toward degradation and contributes to the aged tissues’ increased sensitivity to ischemic insults. Altogether, our data provide fresh perspectives on the processes underlying ischemic injury in the aging brain and serve as a freely accessible resource for upcoming research. Keywords: extracellular matrix, stroke, aging, genes, proteins

CITATION EXPORT

Martina Chmelova, Peter Androvic, Denisa Kirdajova et al.. A view of the genetic and proteomic profile of extracellular matrix molecules in aging and stroke. Frontiers in Cellular Neuroscience. (2023). https://doi.org/10.3389/fncel.2023.1296455

AUTHORS

8 · 3 CENTRES

Martina Chmelova, Peter Androvic, Denisa Kirdajova, Jana Tureckova, Jan Kriska, Lukas Valihrach, Miroslava Anderova, Lydia Vargova

1Department of Neuroscience, Second Faculty of Medicine, Charles University, Prague, Czechia
2Department of Cellular Neurophysiology, Institute of Experimental Medicine of the Czech Academy of Sciences, Prague, Czechia
3Laboratory of Gene Expression, Institute of Biotechnology of the Czech Academy of Sciences – BIOCEV, Vestec, Czechia