Immune cell infiltration and the genes associated with ligamentum flavum hypertrophy: Identification and validation

Cellular and Molecular Mechanisms of Hypertrophy of Ligamentum Flavum

Hypertrophy of the ligamentum flavum (HLF) is a common contributor to lumbar spinal stenosis (LSS). Fibrosis is a core pathological factor of HLF resulting in degenerative LSS and associated low back pain. Although progress has been made in HLF research, the specific molecular mechanisms that promote HLF remain to be defined. The molecular factors involved in the onset of HLF include increases in inflammatory cytokines such as transforming growth factor (TGF)-β, matrix metalloproteinases, and pro-fibrotic growth factors. In this review, we discuss the current understanding of the mechanisms involved in HLF with a particular emphasis on aging and mechanical stress. We also discuss in detail how several pathomechanisms such as fibrosis, proliferation and apoptosis, macrophage infiltration, and autophagy, in addition to several molecular pathways involving TGF-β1, mitogen-activated protein kinase (MAPKs), and nuclear factor-κB (NF-κB) signaling, PI3K/AKT signaling, Wnt signaling, micro-RNAs, extracellular matrix proteins, reactive oxygen species (ROS), etc. are involved in fibrosis leading to HLF. We also present a summary of the current advancements in preclinical animal models for HLF research. In addition, we update the current and potential therapeutic targets/agents against HLF. An improved understanding of the molecular processes behind HLF and a novel animal model are key to developing effective LSS prevention and treatment strategies.

Experimental confirmation and bioinformatics reveal biomarkers of immune system infiltration and hypertrophy ligamentum flavum

Background

Hypertrophy ligamentum flavum is a prevalent chronic spinal condition that affects middle-aged and older adults. However, the molecular pathways behind this disease are not well comprehended.

Objective

The objective of this work is to implement bioinformatics techniques in order to identify crucial biological markers and immune infiltration that are linked to hypertrophy ligamentum flavum. Further, the study aims to experimentally confirm the molecular mechanisms that underlie the hypertrophy ligamentum flavum.

Methods

The corresponding gene expression profiles (GSE113212) were selected from a comprehensive gene expression database. The gene dataset for hypertrophy ligamentum flavum was acquired from GeneCards. A network of interactions between proteins was created, and an analysis of functional enrichment was conducted using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) databases. An study of hub genes was performed to evaluate the infiltration of immune cells in patient samples compared to tissues from the control group. Finally, samples of the ligamentum flavum were taken with the purpose of validating the expression of important genes in a clinical setting.

Results

Overall, 27 hub genes that were differently expressed were found through molecular biology. The hub genes were found to be enriched in immune response, chemokine-mediated signaling pathways, inflammation, ossification, and fibrosis processes, as demonstrated by GO and KEGG studies. The main signaling pathways involved include the TNF signaling pathway, cytokine-cytokine receptor interaction, and TGF-β signaling pathway. An examination of immunocell infiltration showed notable disparities in B cells (naïve and memory) and activated T cells (CD4 memory) between patients with hypertrophic ligamentum flavum and the control group of healthy individuals. The in vitro validation revealed markedly elevated levels of ossification and fibrosis-related components in the hypertrophy ligamentum flavum group, as compared to the normal group.

Conclusion

The TGF-β signaling pathway, TNF signaling pathway, and related hub genes play crucial roles in the progression of ligamentum flavum hypertrophic. Our study may guide future research on fibrosis of the ligamentum flavum.

Nonsurgical therapy for lumbar spinal stenosis caused by ligamentum flavum hypertrophy: A review

Lumbar spinal stenosis (LSS) can cause a range of cauda equina symptoms, including lower back and leg pain, numbness, and intermittent claudication. This disease affects approximately 103 million people worldwide, particularly the elderly, and can seriously compromise their health and well-being. Ligamentum flavum hypertrophy (LFH) is one of the main contributing factors to this disease. Surgical treatment is currently recommended for LSS caused by LFH. For patients who do not meet the criteria for surgery, symptom relief can be achieved by using oral nonsteroidal anti-inflammatory drugs (NSAIDs) and epidural steroid injections. Exercise therapy and needle knife can also help to reduce the effects of mechanical stress. However, the effectiveness of these methods varies, and targeting the delay in LF hypertrophy is challenging. Therefore, further research and development of new drugs is necessary to address this issue. Several new drugs, including cyclopamine and N-acetyl-l-cysteine, are currently undergoing testing and may serve as new treatments for LSS caused by LFH.

Comparative Gene-Expression Analysis of the Ligamentum Flavum of Patients with Lumbar Spinal Canal Stenosis: Comparison between the Dural and Dorsal Sides of the Thickened Ligamentum Flavum

Thickening of the ligamentum flavum is the main factor in the development of lumbar spinal canal stenosis (LSCS). Although previous studies have reported factors related to ligamentum flavum thickening, its etiology has not been clarified. Furthermore, it is often difficult to set proper controls to investigate the pathologies of thickening due to differences in patient characteristics, such as age, sex, obesity, and comorbidities. This study aimed to elucidate the pathologies of ligamentum flavum thickening by comparing the dural and dorsal sides of the thickened ligamentum flavum in patients with LSCS. Ligamentum flavum samples were collected from 19 patients with LSCS. The samples were divided into the dural and dorsal sides. The dural side was used as a control to assess the pathologies occurring on the dorsal side. Elastic Masson staining was used to assess the elastic fibres. Gene expression levels were comprehensively assessed using quantitative reverse transcription polymerase chain reaction and DNA microarray analyses. Gene ontology analysis was used to identify biological processes associated with differentially expressed genes. The elastic fibres were significantly decreased on the dorsal side of the thickened ligamentum flavum. Genes related to fibrosis, inflammation, tissue repair, remodeling, and chondrometaplasia, such as COL1A2, COL3A1, COL5A1, TGFB1, VEGFA, TNFA, MMP2, COL10A1, and ADAMTS4, were highly expressed on the dorsal side of the thickened ligamentum flavum. The biological processes occurring on the dorsal side of the thickened ligamentum flavum were extracellular matrix organization, cell adhesion, extracellular matrix disassembly, and proteolysis.These are considered important pathologies of ligamentum flavum thickening.

Integrated Bioinformatics Analysis for Revealing CBL is a Potential Diagnosing Biomarker and Related Immune Infiltration in Parkinson's Disease

Purpose

There is growing evidence that the immune system plays an important role in the progression of Parkinson's disease, the second most common neurodegenerative disorder. This study aims to address the comprehensive understanding of the immunopathogenesis of Parkinson's disease and explore new inflammatory biomarkers.

Patients and Methods

In this study, Immune-related differential expressed genes (DEIRGs) were obtained from GEO database and Immport database. The hub gene was screened in DEIRGs using LASSO regression and random forest algorithm, and the mRNA expression of the identified hub gene was validated using clinical blood samples.

Results

We obtained a total of 157 DEIRGs that played an important role in the immune response. The results of immune cell infiltration analysis showed that the degree of memory B cells infiltration was higher in PD patients, while the degree of Monocytes, resting mast cells and M0 macrophages infiltration was lower (p<0.05). A total of 8 hub genes were screened by machine learning methods, and RT-PCR results showed that the expression level of CBL gene in PD was significantly increased (p<0.05).

Conclusion

Our findings suggest that CBL is a new potential diagnostic biomarker for PD and that abnormal immune cell infiltration may influence PD development.

Spinal calcifying pseudoneoplasm of the neuraxis (CAPNON) associated with facet joint pathologies: CAPNON diagnostic and pathogenic insights

Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a rare tumor-like fibro-osseous lesion that can develop anywhere in the neuraxis. Approximately a half of reported CAPNONs developed in the spinal region, mostly close to the facet joint (FJ). The diagnosis of spinal CAPNONs is challenging given the existence of mimics and associated pathologies including calcific degeneration of the FJ ligaments (DFJL) and synovial cysts (SCs). The pathogenesis of CAPNON remains elusive, although there have been a few hypotheses including degenerative, reactive, proliferative and immune-mediated processes. Our present study examined clinical, radiological and pathological features of 12 spinal CAPNONs in comparison to 9 DFJL foci, and diagnostic and pathogenic relationship between CAPNONs and FJ pathologies. On imaging, CAPNONs were all tumor-like and typically bigger than DFJL foci. All CAPNONs showed pathologically diagnostic features including characteristic cores, consistently identifiable core-surrounding/peripheral palisading of macrophages and other cells including multinucleated giant cells, variable infiltration of CD8+ T-cells, and multifocal immunopositivity of neurofilament light chain (NF-L). These features were absent or limited in the DFJL foci with statistically significant differences from CAPNONs, except calcifications. Spinal CAPNONs co-existed with DFJL foci in all cases; some had transitional foci with overlapping focal CAPNON and DFJL-like features. These findings, along with our previously reported relationship between CAPNONs and SCs, suggest that spinal CAPNONs may occur in association with or in transition from calcifying/calcified degenerative lesions of FJ ligaments and/or SCs when a reactive proliferative process is complemented by other pathogenic changes such as immune-mediated pathology and NF-L deposition/expression.

Machine learning-based integration identifies the ferroptosis hub genes in nonalcoholic steatohepatitis

BACKGROUND

Ferroptosis, is characterized by lipid peroxidation of fatty acids in the presence of iron ions, which leads to cell apoptosis. This leads to the disruption of metabolic pathways, ultimately resulting in liver dysfunction. Although ferroptosis is linked to nonalcoholic steatohepatitis (NASH), understanding the key ferroptosis-related genes (FRGs) involved in NASH remains incomplete. NASH may be targeted therapeutically by identifying the genes responsible for ferroptosis.

METHODS

To identify ferroptosis-related genes and develop a ferroptosis-related signature (FeRS), 113 machine-learning algorithm combinations were used.

RESULTS

The FeRS constructed using the Generalized Linear Model Boosting algorithm and Gradient Boosting Machine algorithms exhibited the best prediction performance for NASH. Eight FRGs, with ZFP36 identified by the algorithms as the most crucial, were incorporated into in FeRS. ZFP36 is significantly enriched in various immune cell types and exhibits significant positive correlations with most immune signatures.

CONCLUSION

ZFP36 is a key FRG involved in NASH pathogenesis.