Fish Collagen Peptides Protect against Cisplatin-Induced Cytotoxicity and Oxidative Injury by Inhibiting MAPK Signaling Pathways in Mouse Thymic Epithelial Cells

HO-1 activation contributes to cadmium-induced ferroptosis in renal tubular epithelial cells via increasing the labile iron pool and promoting mitochondrial ROS generation

Cadmium (Cd), a prevalent environmental contaminant, has attracted widespread attention due to its serious health hazards. Ferroptosis is a form of iron-dependent oxidative cell death that contributes to the development of various kidney diseases. However, the mechanisms underlying the occurrence of ferroptosis in Cd-induced renal tubular epithelial cells (TECs) have not been fully elucidated. Hereby, both in-vitro and in-vivo experiments were established to elucidate this issue. In this study, we found that Cd elicited accumulation of lipid peroxides due to intracellular ferrous ion (Fe2+) overload and glutathione depletion, contributing to ferroptosis. Inhibition of ferroptosis via chelation of Fe2+ or reduction of lipid peroxidation can significantly mitigate Cd-induced cytotoxicity. Renal transcriptome analysis revealed that the activation of heme oxygenase 1 (HO-1) was closely related to ferroptosis in Cd-induced TECs injury. Cd-induced ferroptosis and resultant TECs injury are significantly alleviated due to HO-1 inhibition, demonstrating the crucial role of HO-1 in Cd-triggered ferroptosis. Further studies showed that accumulation of lipid peroxides due to iron overload and mitochondrial ROS (mtROS) generation was responsible for HO-1-triggered ferroptosis in Cd-induced cytotoxicity. In conclusion, the current study demonstrates that excessively upregulating HO-1 promotes iron overload and mtROS overproduction to trigger ferroptosis in Cd-induced TECs injury, highlighting that targeting HO-1-mediated ferroptosis may provide new ideas for preventing Cd-induced nephrotoxicity.

In Vivo Tracking and 3D Mapping of Cell Death in Regeneration and Cancer Using Trypan Blue

Tracking cell death in vivo can enable a better understanding of the biological mechanisms underlying tissue homeostasis and disease. Unfortunately, existing cell death labeling methods lack compatibility with in vivo applications or suffer from low sensitivity, poor tissue penetration, and limited temporal resolution. Here, we fluorescently labeled dead cells in vivo with Trypan Blue (TBlue) to detect single scattered dead cells or to generate whole-mount three-dimensional maps of large areas of necrotic tissue during organ regeneration. TBlue effectively marked different types of cell death, including necrosis induced by CCl4 intoxication in the liver, necrosis caused by ischemia-reperfusion in the skin, and apoptosis triggered by BAX overexpression in hepatocytes. Moreover, due to its short circulating lifespan in blood, TBlue labeling allowed in vivo "pulse and chase" tracking of two temporally spaced populations of dying hepatocytes in regenerating mouse livers. Additionally, upon treatment with cisplatin, TBlue labeled dead cancer cells in livers with cholangiocarcinoma and dead thymocytes due to chemotherapy-induced toxicity, showcasing its utility in assessing anticancer therapies in preclinical models. Thus, TBlue is a sensitive and selective cell death marker for in vivo applications, facilitating the understanding of the fundamental role of cell death in normal biological processes and its implications in disease.

Effect of Spirulina and Fish Processing By-Products Extracts on Citrinin-Induced Cytotoxicity in SH-SY5Y Cells

Citrinin (CIT) is a mycotoxin commonly found in grains, fruits, herbs, and spices. Its toxicity primarily affects the kidney and liver. Meanwhile, food industry by-products, particularly from fishing and aquaculture, contribute significantly to environmental concerns but can also serve as valuable sources of nutrients and bioactive compounds. Additionally, microalgae like spirulina (Arthrospira platensis) offer interesting high-added-value compounds with potential biological and cytoprotective properties. This study aims to reduce CIT's toxicity on SH-SY5Y cells using natural extracts from the microalgae spirulina and fish processing by-products (sea bass head). The combination of these extracts with CIT has shown increased cell viability up to 15% for fish by-products extract and about 10% for spirulina extract compared to CIT alone. Furthermore, a notable reduction of up to 63.2% in apoptosis has been observed when fish by-products extracts were combined with CIT, counteracting the effects of CIT alone. However, the extracts' effectiveness in preventing CIT toxicity in the cell cycle remains unclear. Overall, considering these nutrient and bioactive compound sources is crucial for enhancing food safety and mitigating the harmful effects of contaminants such as mycotoxins. Nevertheless, further studies are needed to investigate their mechanisms of action and better understand their protective effects more comprehensively.

Attenuative effects of collagen peptide from milkfish (Chanos chanos) scales on ovariectomy-induced osteoporosis

Osteoporosis is characterized by low bone mass, bone microarchitecture disruption, and collagen loss, leading to increased fracture risk. In the current study, collagen peptides were extracted from milkfish scales (MS) to develop potential therapeutic candidates for osteoporosis. MS was used to synthesize a crude extract of fish scales (FS), collagen liquid (COL), and hydroxyapatite powder (HA). COL samples were further categorized according to the peptide size of total COL (0.1 mg/mL), COL < 1 kDa (0.1 mg/mL), COL: 1-10 kDa (0.1 mg/mL), and COL > 10 kDa (0.1 mg/mL) to determine it. Semi-quantitative reverse transcription polymerase chain reaction (sqRT-PCR) and immunofluorescence labeling were used to assess the expression levels of specific mRNA and proteins in vitro. For in vivo studies, mice ovariectomy (OVX)-induced postmenopausal osteoporosis were developed, while the sham surgery (Sham) group was treated as a control. Collagen peptides (CP) from MS inhibited osteoclast differentiation in RAW264.7 cells following an insult with nuclear factor kappa-B ligand (RANKL). CP also enhanced osteoblast proliferation in MG-63 cells, possibly through downregulating NFATc1 and TRAP mRNA expression and upregulating ALP and OPG mRNA levels. Furthermore, COL1 kDa also inhibited bone density loss in osteoporotic mice. Taken together, CP may reduce RANKL-induced osteoclast activity while promoting osteoblast synthesis, and therefore may act as a potential therapeutic agent for the prevention and control of osteoporosis.

Fish Collagen Peptides Enhance Thymopoietic Gene Expression, Cell Proliferation, Thymocyte Adherence, and Cytoprotection in Thymic Epithelial Cells via Activation of the Nuclear Factor-κB Pathway, Leading to Thymus Regeneration after Cyclophosphamide-Induced Injury

Prolonged thymic involution results in decreased thymopoiesis and thymic output, leading to peripheral T-cell deficiency. Since the thymic-dependent pathway is the only means of generating fully mature T cells, the identification of strategies to enhance thymic regeneration is crucial in developing therapeutic interventions to revert immune suppression in immunocompromised patients. The present study clearly shows that fish collagen peptides (FCPs) stimulate activities of thymic epithelial cells (TECs), including cell proliferation, thymocyte adhesion, and the gene expression of thymopoietic factors such as FGF-7, IGF-1, BMP-4, VEGF-A, IL-7, IL-21, RANKL, LTβ, IL-22R, RANK, LTβR, SDF-1, CCL21, CCL25, CXCL5, Dll1, Dll4, Wnt4, CD40, CD80, CD86, ICAM-1, VCAM-1, FoxN1, leptin, cathepsin L, CK5, and CK8 through the NF-κB signal transduction pathway. Furthermore, our study also revealed the cytoprotective effects of FCPs on TECs against cyclophosphamide-induced cellular injury through the NF-κB signaling pathway. Importantly, FCPs exhibited a significant capability to facilitate thymic regeneration in mice after cyclophosphamide-induced damage via the NF-κB pathway. Taken together, this study sheds light on the role of FCPs in TEC function, thymopoiesis, and thymic regeneration, providing greater insight into the development of novel therapeutic strategies for effective thymus repopulation for numerous clinical conditions in which immune reconstitution is required.

Recovery of Bioactive Compounds from Marine Organisms: Focus on the Future Perspectives for Pharmacological, Biomedical and Regenerative Medicine Applications of Marine Collagen

Marine environments cover more than 70% of the Earth's surface and are among the richest and most complex ecosystems. In terms of biodiversity, the ocean represents an important source, still not widely exploited, of bioactive products derived from species of bacteria, plants, and animals. However, global warming, in combination with multiple anthropogenic practices, represents a serious environmental problem that has led to an increase in gelatinous zooplankton, a phenomenon referred to as jellyfish bloom. In recent years, the idea of "sustainable development" has emerged as one of the essential elements of green-economy initiatives; therefore, the marine environment has been re-evaluated and considered an important biological resource. Several bioactive compounds of marine origin are being studied, and among these, marine collagen represents one of the most attractive bio-resources, given its use in various disciplines, such as clinical applications, cosmetics, the food sector, and many other industrial applications. This review aims to provide a current overview of marine collagen applications in the pharmacological and biomedical fields, regenerative medicine, and cell therapy.