Hydrolyzed tilapia fish collagen modulates the biological behavior of macrophages under inflammatory conditions

A mini-invasive injectable hydrogel for temporomandibular joint osteoarthritis: Its pleiotropic effects and multiple pathways in cartilage regeneration

There are two bottlenecks in the treatment of TMJOA (temporomandibular joint osteoarthritis): ① lacking of easy-to-use repairing materials for damaged condylar cartilage; ② local inflammation interfering with in situ regeneration. In response to them, we constructed a biomimetic tilapia type I gelatin/hyaluronic acid (TGI/HA) hydrogel in this paper. It was endowed with the capability to immunoregulate mircoenvironment and concurrently induce regeneration in multiple ways. It not only reduced excretion of ECM-degrading enzymes and inflammatory factors, therefore reversing local inflammation, but also created microenvironment conducive to reparation by acting upon macrophages and T cells. In in vivo experiments, the TGI/HA hydrogel effectively restored the damaged cartilage on rat condyle, suggesting it had potential in clinical application.

Comparative transcriptome analysis of albino northern snakehead (Channa argus) reveals its various collagen-related DEGs in caudal fin cells

The albino northern snakehead (Channa argus) is an aquaculture species characterized by heritable albino body color, in contrast to the typical coloration. Additionally, there are gray- and golden-finned individuals, which exhibit distinct coloration in their caudal fins. We performed RNA-seq to profile the transcriptome of caudal fin tissues in albino gray-finned and golden-finned C. argus, contrasting these with normal morphs to elucidate the differences between the two groups. A total of 137,130 unigenes were identified in this study. Gene Ontology (GO) analysis showed that the identified DEGs were significantly enriched in cellular components related to cytoplasm. So far, 379 common DEGs have been identified in all three groups. Notably, we observed more DEGs in golden-finned individuals compared to gray-finned individuals. We also revealed that golden-finned individuals were enriched in collagen-related pathways compared with normal individuals. The enriched DEGs of collagen components include collagen I of COL1A1 and COL1A2, collagen II of COL2A1, collagen V of COL5A1 and COL5A2, collagen VI of COL6A1 and COL6A3, collagen IX of COL9A3, collagen X of COL10A1, collagen XI of COL11A2, collagen XII of COL12A1, collagen XVI of COL16A1, collagen XVIII of COL18A1 and decorin (DCN), all of which play a role in modulating the collagen matrix. In golden-finned albino fish, collagen-related genes were downregulated, suggesting that despite the abundance of collagen types in their caudal fin cells, gene expression was slightly limited. This work provides valuable genetic insights into collagen variation in albino C. argus, lays the foundation for research on collagen genes and is crucial for the development and utilization of fish-derived collagen as a biomaterial for tissue engineering and biomedical applications.

The emerging role of tranexamic acid and its principal target, plasminogen, in skeletal health

The worldwide burden of skeletal diseases such as osteoporosis, degenerative joint disease and impaired fracture healing is steadily increasing. Tranexamic acid (TXA), a plasminogen inhibitor and anti-fibrinolytic agent, is used to reduce bleeding with high effectiveness and safety in major surgical procedures. With its widespread clinical application, the effects of TXA beyond anti-fibrinolysis have been noticed and prompted renewed interest in its use. Some clinical trials have characterized the effects of TXA on reducing postoperative infection rates and regulating immune responses in patients undergoing surgery. Also, several animal studies suggest potential therapeutic effects of TXA on skeletal diseases such as osteoporosis and fracture healing. Although a direct effect of TXA on the differentiation and function of bone cells in vitro was shown, few mechanisms of action have been reported. Here, we summarize recent findings of the effects of TXA on skeletal diseases and discuss the underlying plasminogen-dependent and -independent mechanisms related to bone metabolism and the immune response. We furthermore discuss potential novel indications for TXA application as a treatment strategy for skeletal diseases.

Assessment of Tilapia Skin Collagen for Biomedical Research Applications in Comparison with Mammalian Collagen

Collagen is an important material for biomedical research, but using mammalian tissue-derived collagen carries the risk of zoonotic disease transmission. Marine organisms, such as farmed tilapia, have emerged as a safe alternative source of collagen for biomedical research. However, the tilapia collagen products for biomedical research are rare, and their biological functions remain largely unexamined. In this study, we characterized a commercial tilapia skin collagen using SDS-PAGE and fibril formation assays and evaluated its effects on skin fibroblast adhesion, proliferation, and migration, comparing it with commercial collagen from rat tails, porcine skin, and bovine skin. The results showed that tilapia skin collagen is a type I collagen, similar to rat tail collagen, and has a faster fibril formation rate and better-promoting effects on cell migration than porcine and bovine skin collagen. We also confirmed its application in a 3D culture for kidney cells' spherical cyst formation, fibroblast-induced gel contraction, and tumor spheroid interfacial invasion. Furthermore, we demonstrated that the freeze-dried tilapia skin collagen scaffold improved wound closure in a mouse excisional wound model, similar to commercial porcine or bovine collagen wound dressings. In conclusion, tilapia skin collagen is an ideal biomaterial for biomedical research.

Purified fish skin collagen hydrolysate attenuates TNF-α induced barrier dysfunction in-vitro and DSS induced colitis in-vivo model

Inflammatory mediators are key components in establishing pathogenesis in inflammatory bowel disease. Balanced expression of anti-inflammatory and pro-inflammatory cytokines is an important cue in maintaining gut native and adaptive immunity. In the present study, purified hydrolysate fraction of fish skin collagen from Clarias batrachus and Pangasius pangasius was evaluated as a treatment agent against TNF-α induced barrier dysfunction in Caco-2 cell line model and DSS induced colitis in mice model. Cell adhesion on purified hydrolysate fraction coated surfaces was found to be enhanced with increasing concentration in both Clarias batrachus and Pangasius pangasius. Alkaline phosphatase activity was enhanced in a concentration-dependent manner. The paracellular permeability assay demonstrated that Pangasius pangasius purified hydrolysate fraction had countered TNF-α induced barrier dysfunction. Analysis of the tight junction proteins (occludin, zonulae occluden, and claudin) by RT PCR, immunofluorescence, and western blot, further confirmed the effectiveness of Pangasius pangasius purified hydrolysate fraction against TNF-α. The Pangasius pangasius purified hydrolysate fraction was further evaluated for efficacy in DSS-induced colitis mice model. Two concentration of Pangasius pangasius purified hydrolysate was chosen based on in-vitro experiments, 80 μg/kg and 200 μg/kg BW of Balb/C male mice administered through intra-rectal route along with fish skin collagen 80 μg/kg BW. Pangasius pangasius purified hydrolysate fraction treatment improved the clinical signs of colitis such as body weight, rectal bleeding, colon length, and stool consistency caused by DSS administration. Immunofluorescence of colon tissue section showed that Pangasius pangasius purified hydrolysate fraction enhanced the expression of occludin protein. This study hints at the use of Pangasius pangasius purified hydrolysate fraction as a potential nutraceutical or treatment agent in healing ulcers of the mucosa.

A bioinspired and high-strengthed hydrogel for regeneration of perforated temporomandibular joint disc: Construction and pleiotropic immunomodulatory effects

Due to the lack of an ideal material for TMJ (temporomandibular joint) disc perforation and local inflammation interfering with tissue regeneration, a functional TGI/HA-CS (tilapia type I gelatin/hyaluronic acid-chondroitin sulfate) double network hydrogel was constructed in this paper. It was not only multiply bionic in its composition, structure and mechanical strength, but also endowed with the ability to immunomodulate microenvironment and simultaneously induce in situ repair of defected TMJ discs. On the one hand, it inhibited inflammatory effects of inflammasome in macrophages, reduced the extracellular matrix (ECM)-degrading enzymes secreted by chondrocytes, reversed the local inflammatory state, promoted the proliferation of TMJ disc cells and induced fibrochondrogenic differentiation of synovium-derived mesenchymal stem cells (SMSCs). On the other hand, it gave an impetus to repairing a relatively-large (6 mm-sized) defect in mini pigs' TMJ discs in a rapid and high-quality manner, which suggested a promising clinical application.

Preparation and properties of caffeic-chitosan grafting fish bone collagen peptide

In this study, a novel peptide grafted chitosan (CACS-FBP) with high peptide content, excellent moisture-absorption and moisture-retention abilities was prepared. Caffeic acid (CA) was used to modify chitosan, the highly water-soluble intermediate further reacted with fish bone collagen peptide to obtain the final product, and the synthesis of CACS-FBP was confirmed by the Fourier transform infrared spectroscopy (FT-IR), NMR, and UV-vis. The single-factor experiments indicated that the degree of substitution (DS) of CACS-FBP depended on the reaction temperature, reaction time, the mass ratio of fish bone collagen peptide to CACS (mFBP/mCACS) and the mass ratio of MTGase to CACS (mMTGase/mCACS). In addition, the antioxidant assay indicated that CACS-FBP had an excellent antioxidant capacity, and the CACS-FBP showed no cytotoxicity toward L929 mouse fibroblasts, all the results mean that the prepared peptide-containing chitosan derivative has potential application in pharmaceutical and biomedical fields.

Role of fish collagen hydrolysate in attenuating inflammation-An in vitro study

Collagen hydrolysate, an extensively used protein obtained from different sources, has various beneficial effects on human health and diseases. The benefits of collagen hydrolysate are well known and presently varied sources for the preparation of hydrolysate are being investigated. Food as a therapy to combat inflammation is presently a much-focused field of research. The present study aims at screening the anti-inflammatory property of collagen hydrolysate from the skin of Cypselurus melanurus, Catla catla, Indian mackerel, Clarias batrachus (Cb), and Pangasius pangasius (Pp) in activated RAW 264.7 macrophage cells. The fractions, Cb (C2) and Pp (P2) with anti-inflammatory property obtained after two-step chromatographic purification contained peptides in the range of 1-3 kDa molecular weight. The active fractions C2 and P2 showed a reduction in gene expression of TNF-α to 1.6- and 1-fold difference, whereas IL6 expression to 30- and 40-fold difference, respectively, in comparison to LPS treatment. The suppression of inflammatory proteins (TNF-α, IL6, NFκB, and p-IκB) by fractions C2 and P2 confirmed the anti-inflammatory activity. PRACTICAL APPLICATIONS: Collagen hydrolysate and its derived low molecular weight peptides are of great interest in the field of nutraceuticals and biomedical applications. The purified peptide fraction of fish skin hydrolysate displayed a promising anti-inflammatory property. The collagen hydrolysate of Cb and Pp can be a functional food or its purified fraction used as a nutraceutical supplementation due to their anti-inflammatory property in the cellular microenvironment.

Application of marine collagen for stem-cell-based therapy and tissue regeneration (Review)

Tissue engineering and regenerative medicine is becoming an important component in modern biological scientific research. Tissue engineering, a branch of regenerative medicine, is a field that is actively developing to meet the challenges presented in biomedical applications. This particularly applies to the research area of stem cells and biomaterials, due to both being pivotal determinants for the successful restoration or regeneration of damaged tissues and organs. Recently, the development of innovative marine collagen-based biomaterials has attracted attention due to the reported environmentally friendly properties, the lack of zoonotic disease transmission, biocompatibility, bioactivity, the lack of ethics-related concerns and cost-effectiveness for manufacturing. The present review aimed to summarize the potential application and function of marine collagen in stem cell research in a medical and clinical setting. In addition, the present review cited recent studies regarding the latest research advances into using marine collagen for cartilage, bone, periodontal and corneal regeneration. It also characterized the distinct advantages of using marine collagen for stem cell-based tissue repair and regeneration. In addition, the present review comprehensively discussed the most up to date information on stem cell biology, particularly the possibility of treating stem cells with marine collagen to maximize their multi-directional differentiation capability, which highlights the potential use of marine collagen in regenerative medicine. Furthermore, recent research progress on the potential immunomodulatory capacity of mesenchymal stem cells following treatment with marine collagen to improve the understanding of cell-matrix interactions was investigated. Finally, perspectives on the possible future research directions for the application of marine collagen in the area of regenerative medicine are provided.

Biocompatibility, hemostatic properties, and wound healing evaluation of tilapia skin collagen sponges

Dialyzed tilapia skin collagen sponge (DTSCS) and self-assembled tilapia skin collagen sponge (STSCS) were prepared by freeze-drying. The raw components used in the fabrication of DTSCS and STSCS were separated and purified from tilapia fish skin. It is anticipated that these collagen sponges could be developed into medical dressings for hemostasis and wound healing. The aim of the present research was to explore the possibility of DTSCS and STSCS as medical dressings and compare their differences by scanning electron microscopy (SEM), water absorption measurement, differential scanning calorimetry (DSC), measurement of porosity, cytotoxicity, hemolysis, in vivo biocompatibility, and evaluation of hemostatic performance and wound healing. The results indicate that DTSCS and STSCS are suitable materials for use in medical applications with a loose and porous structure, high water absorption, high porosity, and high thermal stability. The materials also displayed good biocompatibility, including excellent blood compatibility, a lack of cytotoxicity, with no apparent rejection following implantation. STSCS exhibited rapid hemostasis and promoted healing, with slightly greater efficacy than DTSCS. The hemostatic properties and promotion of healing in DTSCS was similar to that of commercial bovine collagen sponge. Therefore, DTSCS and STSCS both represented excellent potential candidate materials for use as hemostatic agents and wound dressings.

Impact of Marine-Based Biomaterials on the Immunoregulatory Properties of Bone Marrow-Derived Mesenchymal Stem Cells: Potential Use of Fish Collagen in Bone Tissue Engineering

A key issue in the field of tissue engineering and stem cell therapy is immunological rejection after the implantation of allogeneic bone marrow-derived mesenchymal stem cells (BMSCs). In addition, maintaining the immunoregulatory function of BMSCs is critical to achieving tissue repair. In recent years, scientists have become interested in fish collagen because of its unique osteoinductive activity. However, it is still unclear whether osteogenically differentiated BMSCs induced by fish collagen maintain their immunoregulatory functions. To address this question, BMSCs were isolated from 8-week-old male BALB/c mice, and a noncontact coculture model was established consisting of macrophages and BMSCs treated with hydrolyzed fish collagen (HFC). Cell proliferation of the macrophages was determined by MTT. The gene and protein expression levels of the M1 and M2 macrophage markers were measured by real-time PCR and enzyme-linked immunosorbent assay (ELISA). To study the role of TNF-α-induced gene/protein 6 (TSG-6), TSG-6 was targeted by short interfering RNA (siRNA) in BMSCs, then the osteogenic differentiation ability of the BMSCs was examined by western blotting. The mRNA expression levels of interleukin-10 (IL-10), CCL22 (a macrophage-derived chemokine), tumor necrosis factor α (TNF-α), and interleukin-12 (IL-12), and the protein expression levels of arginase-1 (Arg-1) and inducible nitric oxide synthase (iNOS) of macrophages cocultured with TSG-6-siRNA-BMSCs+HFC were detected by real-time PCR and western blotting, respectively. The results showed that the osteogenically differentiated BMSCs induced by HFC did not affect the proliferation of macrophages. Osteogenically differentiated BMSCs induced by HFC promoted the expression of M2 macrophage markers IL-10 and CCL22, while HFC inhibited the expression of M1 macrophage markers, including TNF-α and IL-12. The TSG-6 knockdown led to a decrease in the production of TSG-6 without impairing the expression of bone sialoprotein (BSP), osteocalcin (OCN), and Runt-related transcription factor 2 (RUNX2) by BMSCs. TSG-6 silencing significantly counteracted the effect of HFC, and the expression of IL-10, CCL22, and Arg-1 were all decreased in the macrophages cocultured with TSG-6-siRNA-BMSCs+HFC, while that of TNF-α, IL-12, and iNOS were increased relative to the BMSCs+HFC group. The data demonstrated that osteogenically differentiated BMSCs induced by fish collagen retained their immunomodulatory functions. This study provides an additional scientific basis for future applications of fish collagen as an osteogenic component in the fields of tissue engineering and stem cell therapy.

Modulation of the secretion of mesenchymal stem cell immunoregulatory factors by hydrolyzed fish collagen

The aim of the present study was to investigate the possible immunomodulatory effects of osteogenically differentiated bone marrow mesenchymal stem cells induced by hydrolyzed fish collagen. Marine biomaterials have attracted significant attention for their environmental friendliness and renewability. Hydrolyzed fish collagen (HFC) has been discovered to induce the osteoblastic differentiation of stem cells, which underlies the foundation for its application in tissue engineering. Stem cells and their biomaterial carriers face acute immune rejection mediated by host macrophages. A potential strategy for combatting rejection in stem cell therapy is to modify the polarization of macrophages. However, whether HFC-induced mesenchymal stem cells maintain their immunomodulatory ability remains to be determined. To understand this phenomenon, a co-culture model of direct contact was established between bone marrow mesenchymal stem cells (BMSCs) and RAW264.7 macrophages, where the secretion of nitrous oxide from macrophages was measured using Griess colorimetric assay. ELISAs were performed to measure the secretion of interleukin (IL)-1β, IL-6, transforming growth factor (TGF)-β and IL-10, whilst reverse transcription-quantitative PCR was used to assess the expression levels of IL-1β, IL-6, CD206, resistin-like molecule α (FIZZ1) and prostaglandin E2 receptor 4 (EP4). In addition, the expression levels of relevant proteins in the phosphorylated-cyclic AMP-responsive element-binding protein-CCAAT/enhancer-binding protein β (EBPβ) pathway were investigated using western blotting. HFC-induced BMSCs were found to suppress the expression levels of IL-1β and IL-6, whilst increasing the expression levels of CD206 and FIZZ1 in RAW264.7 macrophages. HFC-induced BMSCs also inhibited the secretion of IL-1β and IL-6, whilst promoting the secretion of TGF-β and IL-10 secretion from RAW264.7 macrophages. Mechanistic studies using western blotting discovered that HFC stimulated the secretion of prostaglandin E2 from BMSCs, which subsequently increased the expression of EP4 on the macrophages. EP4 then increased the expression levels of C/EBPβ and arginase 1 further. In conclusion, results from the present study suggested that following induction with HFC, BMSCs maintain their immunomodulatory activity.

Upgrading of marine (fish and crustaceans) biowaste for high added-value molecules and bio(nano)-materials

Currently, the Earth is subjected to environmental pressure of unprecedented proportions in the history of mankind. The inexorable growth of the global population and the establishment of large urban areas with increasingly higher expectations regarding the quality of life are issues demanding radically new strategies aimed to change the current model, which is still mostly based on linear economy approaches and fossil resources towards innovative standards, where both energy and daily use products and materials should be of renewable origin and 'made to be made again'. These concepts have inspired the circular economy vision, which redefines growth through the continuous valorisation of waste generated by any production or activity in a virtuous cycle. This not only has a positive impact on the environment, but builds long-term resilience, generating business, new technologies, livelihoods and jobs. In this scenario, among the discards of anthropogenic activities, biodegradable waste represents one of the largest and highly heterogeneous portions, which includes garden and park waste, food processing and kitchen waste from households, restaurants, caterers and retail premises, and food plants, domestic and sewage waste, manure, food waste, and residues from forestry, agriculture and fisheries. Thus, this review specifically aims to survey the processes and technologies for the recovery of fish waste and its sustainable conversion to high added-value molecules and bio(nano)materials.

A review on recent advances and applications of fish collagen

During the processing of the fishery resources, the significant portion is either discarded or used to produce low-value fish meal and oil. However, the discarded portion is the rich source of valuable proteins such as collagen, vitamins, minerals, and other bioactive compounds. Collagen is a vital protein in the living body as a component of a fibrous structural protein in the extracellular matrix, connective tissue and building block of bones, tendons, skin, hair, nails, cartilage and joints. In recent years, the use of fish collagen as an increasingly valuable biomaterial has drawn considerable attention from biomedical researchers, owing to its enhanced physicochemical properties, stability and mechanical strength, biocompatibility and biodegradability. This review focuses on summarizing the growing role of fish collagen for biomedical applications. Similarly, the recent advances in various biomedical applications of fish collagen, including wound healing, tissue engineering and regeneration, drug delivery, cell culture and other therapeutic applications, are discussed in detail. These applications signify the commercial importance of fish collagen for the fishing industry, food processors and biomedical sector.

Osteogenically differentiated mesenchymal stem cells induced by hydrolyzed fish collagen maintain their immunomodulatory effects

AIMS

The reciprocity between stem cells and biomaterials is an essential topic in bone tissue engineering. Bone marrow mesenchymal stromal cells (BMSCs) have attracted considerable attention in regenerative medicine owing to their ability to self-renew and differentiate into osteoblasts, and more importantly, their immunomodulatory effects on the immune response. Ideal biomaterials should be osteo-inductive, environmentally sustainable, and economical. Our previous study showed that hydrolyzed fish collagen (HFC) can meet each of the above requirements. However, it is still unclear whether BMSCs maintain their immunomodulatory properties after osteogenic differentiation induced by HFC.

MAIN METHODS

Non-commercial sources of BMSCs were isolated from Sprague-Dawley (SD) rats. Osteogenically differentiated BMSCs induced by HFC and undifferentiated BMSCs were co-cultured with PBMC or NR 8383 macrophages, respectively. Cell proliferation of PBMC was examined using a BrdU uptake assay. In addition, the IL-6, TGF-β1, IL-10, PGE2, and nitric oxide levels were determined. The expressions of TSG-6 (TNF-stimulated gene 6) and IDO (indoleamine 2, 3-dioxygenase) genes were analyzed using qRT-PCR.

KEY FINDINGS

The results revealed that HFC-induced BMSCs suppressed the proliferation of PBMC. The expression levels of anti-inflammatory mediators including IL-6, TGF-β1, and PGE2 significantly increased after 48 h of co-culture. Moreover, the nitric oxide production increased during osteogenesis induced by HFC, whereas the level of TSG-6 and IDO remained unchanged after osteogenic differentiation. HFC-BMSCs inhibited the inflammatory mediator production (IL-1β, TNF-α) in LPS-stimulated macrophages.

SIGNIFICANCE

Taken together, these findings suggest that the immunomodulation ability is still retained in osteogenically differentiated BMSCs induced by HFC.

Sponges of Carboxymethyl Chitosan Grafted with Collagen Peptides for Wound Healing

Burns are physically debilitating and potentially fatal injuries. Two marine biomaterials, carboxymethyl chitosan (CMC) and collagen peptides (COP), have emerged as promising burn dressings. In this paper, sponges of carboxymethyl chitosan grafted with collagen peptide (CMC–COP) were prepared by covalent coupling and freeze drying. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy were then used to characterize the prepared sponges. To evaluate the wound healing activity of the CMC–COP sponges, in vitro tests including cell viability scratch wound healing and scald wound healing experiments were performed in rabbits. Appearance studies revealed the porous nature of sponges and FTIR spectroscopy demonstrated the successful incorporation of COP into CMC. The in vitro scratch assay showed that treatment with CMC–COP sponges (at 100 μg/mL) had significant effects on scratch closure. For burn wounds treated with CMC–COP, regeneration of the epidermis and collagen fiber deposition was observed on day 7, with complete healing of the epidermis and wound on days 14 and 21, respectively. Based on the pathological examination by hematoxylin and eosinstaining, the CMC–COP group demonstrated pronounced wound healing efficiencies. These results confirmed that the CMC–COP treatment enhanced cell migration and promoted skin regeneration, thereby highlighting the potential application of these sponges in burn care.

Evaluation of the Immunogenicity of a Vascular Graft Covered with Collagen Derived from the European Carp (Cyprinus carpio) and Bovine Collagen

AIM

To assess the systemic and local immunological response to subcutaneous implants of a vascular graft covered with collagen extracted from the European carp (freshwater fish) or with collagen of bovine origin.

METHODS

Pieces of a vascular graft covered by pure bovine (Bos taurus, BOV, n=14) or carp (Cyprinus carpio, CYP, n=14) collagen 5 mm in size were implanted subcutaneously in the dorsum of a Balb/cOla mice. A sham operation group of 12 animals served as the control. At 7 and 14 days after the operation, one-half of each group was terminated and blood for serum, spleen, and implant with surrounding tissue were collected. Mean cytokine (TNF-α, IL-10, IL-4, IL-1β, IL-13, and IFN-γ) levels in serum were determined using ELISA. Spleen cell cultures were used for in vitro testing of lymphocyte proliferation and cytokine secretion. Local expressions of IL-6, IL-10, TNF-α, TGF-β, CCL-2, and CCL-3 were determined using PCR.

RESULTS

We found no significant difference among control, BOV, and CYP groups in mean cytokine serum levels at seven days. At day 14, the BOV group had higher levels of TNF-α (P=.018) and both the BOV and CYP groups had lower levels of IL-4 (P=.011 and P=.047, respectively) compared with the control group. Both tested implants showed only a minimal effect on the production of selected cytokines. Cell proliferation in the CYP group stimulated by CYP gel at 14 days was significantly lower than by BOV gel in BOV group (P=.0031) or by CYP gel in the control group (P=.041). The difference between the groups in the local RNA expression of all the tested mediators both at 7 and at 14 days was not significant apart from a lower level of TNF-α in the BOV group compared to CYP at 14 days (P=.013).

CONCLUSIONS

Implants covered with carp collagen induce an immunological response that is comparable to that of bovine collagen covered implants in a mouse model.

Dual-Functional Dendritic Mesoporous Bioactive Glass Nanospheres for Calcium Influx-Mediated Specific Tumor Suppression and Controlled Drug Delivery in Vivo

The development of nanomaterials for stable, controlled delivery of drugs and efficient suppression of tumor growth with desirable biosafety remains challenging in the nano-biomedical field. In this study, we prepared and optimized mesoporous bioactive glass (MBG) nanospheres to establish a functional drug delivery system and analyzed the effect of the dendritic mesoporous structure on drug loading and release. We then utilized an in vitro model to examine the biological effects of dendritic MBG nanospheres on normal and tumor cells and studied the molecular mechanism underlying specific tumor suppression by MBG nanospheres. Finally, we investigated the combinational effect of MBG nanospheres and a cancer therapeutic drug with an in vivo tumor xenograft model. Our results show that the dendritic MBG nanospheres have been successfully synthesized by optimizing calcium: silicon ratio. MBG nanospheres exhibit a dendritic mesoporous structure with a large specific surface area, demonstrate high drug loading efficiency, and release drugs in a controlled fashion to effectively prolong drug half-life. Ca²⁺ in nanospheres activates transient receptor potential channels and calcium-sensing receptor on tumor cells, mediates calcium influx, and directly regulates the calpain-1-Bcl-2-caspase-3 signaling pathway to specifically suppress tumor growth without affecting normal cells. In addition, dendritic MBG nanospheres synergize with cancer drugs to improve antitumor efficacy and reduce systemic toxicity. Dendritic MBG nanospheres with antitumor activity and controlled drug release have been successfully achieved and the underlying molecular mechanism was elucidated, paving the way for translational application.

Cartilage repair in degenerative osteoarthritis mediated by squid type II collagen via immunomodulating activation of M2 macrophages, inhibiting apoptosis and hypertrophy of chondrocytes

Cartilage lesions in degenerative osteoarthritis (OA) are involved with pathological microenvironmental alterations induced by inflammatory macrophages, and apoptotic and/or hypertrophic chondrocytes. However, current non-operative therapies for cartilage repair in OA can rarely achieve long-term and satisfactory outcomes. This study aims to evaluate a newly developed squid type II collagen (SCII) for repairing OA-induced cartilage lesions. Our in vitro data show that SCII induces M2 polarization of macrophages, and activates macrophages to express pro-chondrogenic genes (TGF-β and IGF), which greatly improves the microenvironment around chondrocytes to produce type II collagen and glycosaminoglycan. In addition, glycine in SCII activates glycine receptors on inflammatory chondrocytes to decrease intracellular calcium concentration, leading to effective inhibition of chondrocyte apoptosis and hypertrophy. The in vitro effects of SCII are further confirmed in vivo. In a rat model of OA, SCII increases the ratio of M2 macrophages, elevates the levels of pro-chondrogenic cytokines (TGF-β1 and TGF-β3) in synovial fluid, and inhibits chondrocyte apoptosis and MMP13 production. Our findings show that SCII immunomodulates M2 activation of macrophages to skew the local OA microenvironment towards a pro-chondrogenic atmosphere, and promotes cartilage repair under inflammatory condition. It shows great potential for SCII to be a novel biomaterial for cartilage repair in OA.

Squid type II collagen as a novel biomaterial: Isolation, characterization, immunogenicity and relieving effect on degenerative osteoarthritis via inhibiting STAT1 signaling in pro-inflammatory macrophages

Collagen from marine organisms has a broad prospect in biomedical field, yet the knowledge on marine-derived type II collagen is rare. Herein, a novel type II collagen was successfully isolated from squid cartilage for the first time. After being characterized, the immunogenicity of squid type II collagen (SCII) was evaluated and compared with that of bovine type II collagen (BCII). Then investigations were further conducted for the impacts of SCII on pro-inflammatory macrophages and macrophage chemotaxis. The degenerative osteoarthritis (OA) -relieving effects of SCII were explored using OA rat model in vivo. Our results demonstrated that the isolated SCII maintained triple-superhelical structure of native collagen with high purity. Different from BCII, SCII presented no immunogenicity since it neither induced abnormal proliferation of lymphocytes in vitro nor changed the basic levels of IgM, IgG, anti-type II collagen IgG and CD4⁺/CD8⁺ lymphocytes ratio in vivo. Additionally, SCII also exerted prominent anti-inflammatory effects. SCII significantly reduced the production of pro-inflammatory cytokines by enhancing the activity of TCPTP and subsequently prompting the dephosphorylation of p-STAT1 in pro-inflammatory macrophages. Besides, it indirectly prevented hypertrophic changes of chondrocytes, and markedly impeded chemotaxis of macrophages. Moreover, inflammation condition in OA rats was significantly alleviated under treatment with SCII. These data suggested that the newly developed SCII could not only avoid the immunogenic risks of collagen derived from terrestrial animals, but more importantly, provide new choice for the control and treatment of OA.

Sea cucumber peptides exert anti-inflammatory activity through suppressing NF-κB and MAPK and inducing HO-1 in RAW264.7 macrophages

The anti-inflammatory effect of sea cucumber peptides (SCP) in lipopolysaccharide (LPS)-stimulated RAW264.7 murine macrophages was tested. SCP significantly reduced LPS-induced nitric oxide release by inhibiting the inducible nitric oxide synthase mRNA expression without affecting the cell viability. The mRNA expression of LPS-induced inflammatory cytokines including tumour necrosis factor-α, interleukin (IL)-1β and IL-6 was suppressed. SCP inhibited LPS-induced degradation of the inhibitor of κBα (IκBα) and nuclear transposition of NF-κB p65, resulting in decreased NF-κB transactivation. Moreover, SCP suppressed the LPS-induced phosphorylation of JNK, ERK and p38. In addition, the expression of heme oxygenase (HO)-1 in macrophages was up-regulated by SCP in a dose-dependent manner. The inhibition effect of SCP on the mRNA expression of LPS-induced inflammatory cytokines was partially reversed by co-treatment with a HO-1 inhibitor. The SCP with anti-inflammatory activity was made up of low-molecular-weight peptides rich in glycine, glutamic acid and aspartic acid. Collectively, these results demonstrate that SCP exerts anti-inflammatory function through inhibiting NF-κB and MAPK activation and inducing HO-1 expression in macrophages.