Molecular structure and function analysis of bikunin on down-regulation of tumor necrosis factor-alpha expression in activated neutrophils

Bikunin: A Promising Prognostic Biomarker for Acute-on-Chronic Liver Failure in Patients with Viral Hepatitis B

Purpose

To screen out potential prognostic biomarkers for HBV-related acute-on-chronic liver failure (HBV-ACLF).

Patients and Methods

Peripheral blood samples of HBV-ACLF patients (n=56) and normal controls (n=15) from the Affiliated Hospital of Southwest Medical University from January 2021 to April 2022 were collected, 5 normal patients and 10 patients with ACLF were randomly selected for Data independent acquisition (DIA) mass spectrometry analysis, and the potential core proteins were screened out via bioinformatics. All samples were validated by Enzyme linked immunosorbent assays (ELISA) technology, and the survival curve was constructed based on the patient's 90-day survival time.

Results

A total of 247 differentially expressed proteins (DEPs) were screened, of which 148 were upregulated and 99 were down-regulated. The DEPs were mainly enriched in high-density lipoprotein particle remodeling, coagulation, and hemostasis and participated in signaling pathways such as cholesterol metabolism, coagulation cascades, and PPAR signaling pathway. Finally, bikunin was selected for further study and validated via the ELISA, compared with the normal group, bikunin was poorly expressed in the HBV-ACLF group, the difference was statistically significant (P < 0.0001), the area under the curve (AUC) for Receiver operating characteristic (ROC) analysis was 0.917. Furthermore, compared with the non-survival group, bikunin was highly expressed in the HBV-ACLF survival group, the difference was statistically significant (P=0.0015), and the survival curve showed a positive correlation with patient survival (P=0.0063).

Conclusion

The level of plasma bikunin in HBV-ACLF is down-regulated, which is positively correlated with the survival of the patients with HBV-ACLF, and is expected to become a new prognostic biomarker.

Pentosan Polysulphate (PPS), a Semi-Synthetic Heparinoid DMOAD With Roles in Intervertebral Disc Repair Biology emulating The Stem Cell Instructive and Tissue Reparative Properties of Heparan Sulphate

This review highlights the attributes of pentosan polysulphate (PPS) in the promotion of intervertebral disc (IVD) repair processes. PPS has been classified as a disease modifying osteoarthritic drug (DMOAD) and many studies have demonstrated its positive attributes in the countering of degenerative changes occurring in cartilaginous tissues during the development of osteoarthritis (OA). Degenerative changes in the IVD also involve inflammatory cytokines, degradative proteases and cell signalling pathways similar to those operative in the development of OA in articular cartilage. PPS acts as a heparan sulphate (HS) mimetic to effect its beneficial effects in cartilage. The IVD contains small cell membrane HS-proteoglycans (HSPGs) such as syndecan, and glypican and a large multifunctional HS/chondroitin sulphate (CS) hybrid proteoglycan (HSPG2/perlecan) that have important matrix stabilising properties and sequester, control and present growth factors from the FGF, VEGF, PDGF and BMP families to cellular receptors to promote cell proliferation, differentiation and matrix synthesis. HSPG2 also has chondrogenic properties and stimulates the synthesis of extracellular matrix (ECM) components, expansion of cartilaginous rudiments and has roles in matrix stabilisation and repair. Perlecan is a perinuclear and nuclear proteoglycan in IVD cells with roles in chromatin organisation and control of transcription factor activity, immunolocalises to stem cell niches in cartilage, promotes escape of stem cells from quiescent recycling, differentiation and attainment of pluripotency and migratory properties. These participate in tissue development and morphogenesis, ECM remodelling and repair. PPS also localises in the nucleus of stromal stem cells, promotes development of chondroprogenitor cell lineages, ECM synthesis and repair and discal repair by resident disc cells. The availability of recombinant perlecan and PPS offer new opportunities in repair biology. These multifunctional agents offer welcome new developments in repair strategies for the IVD.

The Inter-α-Trypsin Inhibitor Family: Versatile Molecules in Biology and Pathology

Inter-α-trypsin inhibitor (IαI) family members are ancient and unique molecules that have evolved over several hundred million years of vertebrate evolution. IαI is a complex containing the proteoglycan bikunin to which heavy chain proteins are covalently attached to the chondroitin sulfate chain. Besides its matrix protective activity through protease inhibitory action, IαI family members interact with extracellular matrix molecules and most notably hyaluronan, inhibit complement, and provide cell regulatory functions. Recent evidence for the diverse roles of the IαI family in both biology and pathology is reviewed and gives insight into their pivotal roles in tissue homeostasis. In addition, the clinical uses of these molecules are explored, such as in the treatment of inflammatory conditions including sepsis and Kawasaki disease, which has recently been associated with severe acute respiratory syndrome coronavirus 2 infection in children.

A Retrospective Analysis of the Cartilage Kunitz Protease Inhibitory Proteins Identifies These as Members of the Inter-α-Trypsin Inhibitor Superfamily with Potential Roles in the Protection of the Articulatory Surface

Aim: The aim of this study was to assess if the ovine articular cartilage serine proteinase inhibitors (SPIs) were related to the Kunitz inter-α-trypsin inhibitor (ITI) family. Methods: Ovine articular cartilage was finely diced and extracted in 6 M urea and SPIs isolated by sequential anion exchange, HA affinity and Sephadex G100 gel permeation chromatography. Selected samples were also subjected to chymotrypsin and concanavalin-A affinity chromatography. Eluant fractions from these isolation steps were monitored for protein and trypsin inhibitory activity. Inhibitory fractions were assessed by affinity blotting using biotinylated trypsin to detect SPIs and by Western blotting using antibodies to α1-microglobulin, bikunin, TSG-6 and 2-B-6 (+) CS epitope generated by chondroitinase-ABC digestion. Results: 2-B-6 (+) positive 250, 220,120, 58 and 36 kDa SPIs were detected. The 58 kDa SPI contained α1-microglobulin, bikunin and chondroitin-4-sulfate stub epitope consistent with an identity of α1-microglobulin-bikunin (AMBP) precursor and was also isolated by concanavalin-A lectin affinity chromatography indicating it had N-glycosylation. Kunitz protease inhibitor (KPI) species of 36, 26, 12 and 6 kDa were autolytically generated by prolonged storage of the 120 and 58 kDa SPIs; chymotrypsin affinity chromatography generated the 6 kDa SPI. KPI domain 1 and 2 SPIs were separated by concanavalin lectin affinity chromatography, domain 1 displayed affinity for this lectin indicating it had N-glycosylation. KPI 1 and 2 displayed potent inhibitory activity against trypsin, chymotrypsin, kallikrein, leucocyte elastase and cathepsin G. Localisation of versican, lubricin and hyaluronan (HA) in the surface regions of articular cartilage represented probable binding sites for the ITI serine proteinase inhibitors (SPIs) which may preserve articulatory properties and joint function. Discussion/Conclusions: The Kunitz SPI proteins synthesised by articular chondrocytes are members of the ITI superfamily. By analogy with other tissues in which these proteins occur we deduce that the cartilage Kunitz SPIs may be multifunctional proteins. Binding of the cartilage Kunitz SPIs to HA may protect this polymer from depolymerisation by free radical damage and may also protect other components in the cartilage surface from proteolytic degradation preserving joint function.

Sulfation of the bikunin chondroitin sulfate chain determines heavy chain·hyaluronan complex formation

Inter-α-trypsin inhibitor (IαI) is a complex comprising two heavy chains (HCs) that are covalently bound by an ester bond to chondroitin sulfate (CS), which itself is attached to Ser-10 of bikunin. IαI is essential for the trans-esterification of HCs onto hyaluronan (HA). This process is important for the stabilization of HA-rich matrices during ovulation and some inflammatory processes. Bikunin has been isolated previously by anion exchange chromatography with a salt gradient up to 0.5 M NaCl and found to contain unsulfated and 4-sulfated CS disaccharides. In this study, bikunin-containing fractions in plasma and urine were separated by anion exchange chromatography with a salt gradient of 0.1-1.0 M NaCl, and fractions were analyzed for their reactivity with the 4-sulfated CS linkage region antibody (2B6). The fractions that reacted with the 2B6 antibody (0.5-0.8 M NaCl) were found to predominantly contain sulfated CS disaccharides, including disulfated disaccharides, whereas the fractions that did not react with this antibody (0.1-0.5 M NaCl) contained unsulfated and 4-sulfated CS disaccharides. IαI in the 0.5-0.8 M NaCl plasma fraction was able to promote the trans-esterification of HCs to HA in the presence of TSG-6, whereas the 0.1-0.5 M NaCl fraction had a much reduced ability to transfer HC proteins to HA, suggesting that the CS containing 4-sulfated linkage region structures and disulfated disaccharides are involved in the HC transfer. Furthermore, these data highlight that the structure of the CS attached to bikunin is important for the transfer of HC onto HA and emphasize a specific role of CS chain sulfation.

Anticancer effects of sweet potato protein on human colorectal cancer cells

AIM: To investigate the effects of proteins purified from sweet potato storage roots on human colorectal cancer cell lines.

METHODS: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, Hoechst 33258 nuclear staining and Boyden transwell chamber methods were used to determine whether purified sweet potato protein (SPP) from fresh sweet potato roots affected proliferation, migration and invasion, respectively, of human colorectal cancer SW480 cells in vitro. The inhibitory effects of SPP on growth of human colorectal cancer HCT-8 cells intraperitoneally xenografted in nude mice and spontaneous lung metastasis of murine Lewis lung carcinoma 3LL cells subcutaneously transplanted in C57 BL/6 mice were also investigated in vivo.

RESULTS: SPP inhibited the proliferation of SW480 cells in a dose-dependent manner, with an IC₅₀ value of 38.732 μmol/L (r² = 0.980, P = 0.003) in the MTT assay. Hoechst 33258 nuclear staining further revealed inhibition of cell viability and induction of apoptosis by SPP. The transwell assay disclosed significant reduction in migrated cells/field by 8 μmol/L SPP (8.4 ± 2.6 vs 23.3 ± 5.4, P = 0.031) and invaded cells/field through the ECMatrix by 0.8 μmol/L SPP, compared with the control (25.2 ± 5.2 vs 34.8 ± 6.1, P = 0.038). Both intraperitoneal (ip) and intragastric (ig) administration of SPP led to significant suppression of growth of intraperitoneally inoculated HCT-8 cells in nude mice to 58.0% ± 5.9% (P = 0.037) and 43.5% ± 7.1% (P = 0.004) of the controls, respectively, after 9 d treatment. Bloody ascites additionally disappeared after ip injection of trypsin inhibitor. Notably, ig and ip administration of SPP induced a significant decrease in spontaneous pulmonary metastatic nodule formation in C57 BL/6 mice (21.0 ± 12.3 and 27.3 ± 12.7 nodules/lung vs 42.5 ± 4.5 nodules/lung in controls, respectively, P < 0.05) after 25 d treatment. Moreover, the average weight of primary tumor nodules in the hind leg of mice decreased from 8.2 ± 1.3 g/mice in the control to 6.1 ± 1.4 g/mice in the ip group (P = 0.035).

CONCLUSION: SPP exerts significant antiproliferative and antimetastatic effects on human colorectal cancer cell lines, both in vitro and in vivo.

Biochemical identification and immunolocalizaton of aggrecan, ADAMTS5 and inter-alpha-trypsin-inhibitor in equine degenerative suspensory ligament desmitis

We describe analysis of suspensory ligaments from horses with advanced degenerative suspensory ligament desmitis (DSLD) to identify the major proteoglycans (PGs), ADAMTS-aggrecanases and inter-alpha-trypsin inhibitor (IαI) components associated with ligament degeneration. Specific anatomical regions of suspensory ligaments from two normal horses and four diagnosed with DSLD were analyzed by Western blot and immunohistochemistry for the following: aggrecan, aggrecan fragments, decorin, ADAMTS4, ADAMTS5, and IαI components. When compared to normal, DSLD ligaments showed about a 15-fold increase (P < 0.0014) in aggrecan levels and markedly enhanced staining with Safranin O. The aggrecan was composed of two distinct high molecular weight core protein species. The largest species was found only in DSLD samples and it co-migrated with aggrecan synthesized by equine mesenchymal stem cells (MSC). Many of the DSLD samples also contained abnormally high concentrations of ADAMTS4, ADAMTS5, and IαI. Notably, the ADAMTS5 in DSLD samples, but not normals, was present largely as a high molecular weight complex. We conclude that ligament degeneration in DSLD is associated with matrix changes characteristic of an inflammatory nonhealing wound, specifically containing chondrogenic progenitor cells. Since aggrecan accumulation is a major feature of incomplete healing in tendon and skin of the ADAMTS5 knockout mouse, we propose that ligament failure in DSLD results from a process involving tissue inflammation and the complexation of ADAMTS5.