Can transcription factors in the intervertebral disc of lopinavir/ritonavir prevent degeneration in the nucleus pulposus by mediating the regulation of inflammation through signaling pathways?

OBJECTIVE: This study was conducted to examine whether lopinavir/ritonavir (Lop/r), an HIV protease inhibitor, can improve disc physiology and slow down intervertebral disc (IVD) degeneration through in vitro experimental methods, as well as whether it can suppress inflammation with interleukin-1 beta (IL-1ß) and sex-determining region Y (SRY) protein-related high-mobility group box genes-9 (SOX9) through hypoxia-inducible factor 1-alpha (HIF-1α) and the nuclear factor kappa B (NF-κB) signaling pathway. The aim was to investigate whether Lop/r application is toxic to IVD cells and the microenvironment simultaneously. PATIENTS AND METHODS: Human primary cell cultures were prepared using herniated IVD tissues obtained from patients with lumbar disc hernia who were unresponsive to conservative and medical treatment, and thereby, were operated on. The untreated culture samples served as control group, and the samples treated with Lop/r served as study group. Microscopic evaluations were performed simultaneously using fluorescent and supravital dyes in all groups. In addition to cell viability, toxicity, and proliferation analysis through a commercial kit, IL-1ß, SOX9, HIF-1α, and NF-κB protein expressions were evaluated using Western blotting. In the statistical comparison of the obtained data, an alpha value less than 0.05 was considered significant. RESULTS: Cell proliferation decreased in the Lop/r group, but no cell death was observed (p < 0.05). Moreover, at the end of 72 hours after Lop/r application, IL-1ß and NF-kB protein expressions decreased by 40% and 52%, respectively, while HIF-1α and SOX9 protein expressions increased by 4% and 59%, respectively (p< 0.05). CONCLUSIONS: Although these data were obtained from an in vitro experimental study, it is believed that these findings could make significant contributions to the pharmaco-regenerative treatment modalities of IVD degeneration. Lop/r suppresses the IL-1ß and NF-κB and induces SOX9 and HIF-1α, since these signaling pathways may be related to human IVD degeneration.

Effects of an acetylcholinesterase inhibitor and an N-methyl-D-aspartate receptor antagonist on inflammation and degeneration of the nucleus pulposus.

OBJECTIVE: The study aimed to examine the effects of two drugs, an acetylcholinesterase inhibitor (AChEI) and an N-methyl-D-aspartate receptor (NMDAR) antagonist, on degenerated annulus fibrosus (AF) and nucleus pulposus (NP) cells and the extracellular matrix (ECM) structure in vitro. PATIENTS AND METHODS: Tissue samples were obtained from patients with intervertebral disc herniation (four males and four females; classified as Pfirmann stage IV) and used to prepare cell cultures. Untreated cell culture samples served as the control group. Study group samples were treated with donepezil, memantine or a combination of the two drugs. Cell viability, toxicity and proliferation were evaluated in all groups. Western blotting was used to examine changes in protein expression of signal transducer and activator of transcription 3 (STAT3), phospho-STAT3 (ser727), hypoxia-inducible factor (HIF)-1 alpha (HIF-1α) and nucleotide-binding oligomerisation domain (NOD) leucine-rich repeat (LRR)-containing proteins (NLR) family pyrin domain containing 3 (NLRP3) inflammasome. The alpha significance value was < 0.05. RESULTS: Analysis of the microscopy and commercial kit results revealed that cell proliferation was suppressed, and no cell death was observed. The protein expression levels of NLRP3, STAT3, ser727 and HIF-1α were lower in the samples treated with donepezil and memantine at 72 h (p < 0.05). The protein expression levels of NLRP3, STAT3, ser727 and HIF-1α were higher in the samples treated with the combination of donepezil and memantine (p < 0.05). CONCLUSIONS: The combined administration of memantine a NMDAR antagonist which can prevent neurodegeneration and donepezil an AChEI used for pain relief increased the protein expression levels in the anabolic pathway. However, it did not reduce the protein expression levels in the catabolic pathway. Therefore, further studies are needed to provide extensive insight into whether it may be among the potential targets for the therapy of intervertebral disc (IVD) diseases.

Does oseltamivir protect human chondrocyte and nucleus pulposus cells from degeneration by inhibiting senescence and proinflammation mediated by the NLRP3 inflammasome and NF-κB?

OBJECTIVE: Recent drug design studies suggest that inflammation is among the most important factors in the development of both intervertebral disc (IVD) degeneration (IVDD) and osteoarthritis (OA) due to cartilage damage. This study aimed to investigate whether the anti-inflammatory drug oseltamivir has a toxic effect on IVD and cartilage tissue cells. It assessed what effect oseltamivir has on hypoxia-inducible factor (HIF)-1 alpha (HIF1α), which plays an important role in anabolic pathways in IVD and cartilage tissue. In addition, the study analyzed whether oseltamivir could inhibit the release of inflammatory interleukin-1 beta (IL-1ß) via the nuclear factor kappa-B (NF-κB) signaling pathway by activating the nucleotide-binding oligomerization domain and leucine-rich repeat protein-3 (NLRP3) inflammasome. MATERIALS AND METHODS: Human lumbar IVD (n = 8) tissues were isolated for annulus fibrosus (AF) and nucleus pulposus (NP) primary cell cultures, and human tibial and femoral cartilage tissues (n = 8) were isolated for primary chondrocyte cultures. Untreated groups served as the control and oseltamivir-treated groups as the study sample. Cell viability and cytotoxicity were evaluated at 0, 24, 48, and 72 h in all groups for changes in HIF-1α, IL-1ß, NF-κB, and the NLRP3-inflammasome protein expressions using Western blotting. The α significance value was < 0.05. RESULTS: In the oseltamivir-treated groups, cell proliferation decreased in both AF/NP cell and chondrocyte cultures obtained from IVD cartilage tissues. After Western blotting analysis, changes were observed in the protein expressions of HIF-1α, IL-1ß, NF-κB, and the NLRP3 inflammasome in both AF/NP cells and chondrocytes. The results were statistically significant (p < 0.05). CONCLUSIONS: Oseltamivir treatment may be a promising regenerative strategy to manage IVDD and osteoarthritic cartilage tissues.