Mast Cells and Their Related Gene HK-1 are Closely Associated with Discogenic Low Back Pain: A Bioinformatics and Clinical Sample Study

Abstract

Background

Low back pain (LBP) is primarily caused by intervertebral disc degeneration (IVDD). Immune cells penetrating nucleus pulposus (NP) tissues may play an important role in generating IVDD and LBP.

Methods

The clinical data from 100 cases of IVDD patients was initially analyzed retrospectively. Subsequently, peripheral blood and NP tissues from 41 IVDD patients were gathered for a validated investigation. Among them, ribosome-removed-RNA sequencing (RNA-seq) was performed on 10 cases of NP tissues of specific classifications (VAS 3 and Pfirrmann 3 were used as the controls, while patients with VAS 6 and Pfirrmann 5 were used as the experimental group). Differentially expressed genes (DEGs) were identified for the subsequent bioinformatics analysis. Further methods to confirm the underlying cause of discogenic LBP included mast cell immunohistochemistry (IHC), 12 cytokine detection, Western blot (WB), and real-time polymerase chain reaction (RT-PCR).

Results

Discogenic LBP and IVDD severity are strongly associated, and immunological cell infiltration has been demonstrated to be a significant factor in LBP by bioanalytical research. Tryptase-positive mast cells were found to be significantly more abundant in the VAS 6 NP tissues of IVDD patients than in the VAS 3 NP tissues. It was initially demonstrated that IVDD and LBP were significantly impacted by hemokinin-1 (HK-1), the mast cell-related gene. Furthermore, blood levels of interleukin 12 p70 (IL-12P70) are noticeably elevated and strongly correlated with HK-1, indicating that HK-1 may be involved in the regulation of mast cell activity and IL-12P70 production.

Conclusion

The severity of LBP was observed to be positively correlated with the IVDD Pfirrmann grading. Further research indicates that patients with IVDD may experience persistent low back pain due to HK-1 activation of mast cells and the release of the cytokine IL12P70. This work will offer new insights into the diagnosis and treatment of discogenic LBP.

Keywords:

• IVDD
• LBP
• immune cell infiltration
• mast cell
• HK-1

Abbreviations

LBP, Low back pain; IVDD, Intervertebral disc degeneration; NP, Nucleus pulposus; IHC, Immunohistochemistry; WB, Western blot; RT-PCR, Real-time polymerase chain reaction; TNF-α, Tumor necrosis factor-α; PGE2, Prostaglandin E2; NO, Nitric oxide; ECM, Extracellular matrix; NGF, Nerve growth factor; VEGF, Vascular growth factor; GO, Gene Ontology; KEGG, Kyoto Encyclopedia of Genes and Genomes; WGCNA, Weighted gene co-expression network construction and analysis; TPSB2, Mast cell tryptase; MCs, Mast cells; OA, Osteoarthritis; NF-κB, Nuclear factor-kappaB; IL-12P70, Interleukin 12 p70; MGF, Mast cell growth factor.

Ethics Approval and Informed Consent

The study design was approved by the First Affiliated Hospital, Huzhou University’s ethics committee (approval number: 2019088). All participants in the study provided informed consent before specimens were collected.

Author Contributions

Qian Shi wrote the main manuscript text and prepared all figures. Shouyu He, and Xiaowen Liu contribution to the study design, execution, acquisition of data, analysis and interpretation. All authors contributed to data analysis, drafting or revising the article, have agreed on the journal to which the article will be submitted, gave final approval of the version to be published, and agree to be accountable for all aspects of the work.

Disclosure

There are no conflicts of interest to declare.

Additional information

Funding

This work was supported by the Medicine and Health Project of Zhejiang Province (Grant No. 2020KY941).