Sericin: A Versatile Protein Biopolymer with Therapeutic Significance

Inclusion of reeling wastewater-derived sericin peptides in high-protein nutrition bars for antihardening and storage stability

The utilization of agroindustrial wastes to enrich food protein resources and the exploration of their broader applications are crucial for addressing the food crisis and achieving sustainable development goals. In this study, reeling wastewater-derived sericin was hydrolyzed using papain and trypsin to prepare sericin peptide (SRP) and was used as an antihardening ingredient of high-protein nutrition bars (HPNBs). The mechanism of the antihardening effect of SRP was elucidated by investigating the content of advanced glycation end products and protein oxidation products (carbonyl and free sulfhydryl), and the molecular weight change of HPNBs during storage before and after the addition of SRP. Our results confirmed the fortification of HPNBs with SRP, which is beneficial for the promotion and expansion of sericin applications in the food industry, with positive implications for the rational utilization of protein resources and the enrichment of food protein sources.

Green cocoon-derived sericin reduces cellular damage caused by radiation in human keratinocytes

Radiation therapy used in the treatment of cancer causes skin damage, and no method of care has been established thus far. Recently, it has become clear that sericin derived from silkworm cocoons has moisturizing and antioxidant functions. In addition, green cocoon-derived sericin, which is rich in flavonoids, may have enhanced functions. However, whether this green cocoon-derived sericin can reduce radiotherapy-induced skin damage is unclear. In the present study, we aimed at establishing care methods to reduce skin cell damage caused by X-irradiation using green cocoon-derived sericin. We investigated its effect on human keratinocytes using lactate dehydrogenase activity to indicate damage reduction. Our results showed that green cocoon-derived sericin reduced cell damage caused by X-irradiation. However, this effect was not observed when cells were treated before X-irradiation or with a sericin derived from white cocoons. In addition, green cocoon-derived sericin decreased the levels of reactive oxygen species and lipid peroxidation. Our results suggest that green cocoon sericin mitigates the damaging effect of X-irradiation on cells, hence presenting potential usefulness in reducing skin damage from radiation therapy and opening new avenues in the care of cancer patients.

Therapeutic Potential Evaluation of Silk Sericin Stabilized Fisetin to Ulcerative Colitis

Ulcerative colitis is a chronic inflammatory bowel disease with a high recurrence rate. Natural phytochemical compounds are increasingly being considered as preventative and supportive treatments for this condition. However, the poor water solubility and stability of many of these compounds limit their effectiveness in vivo. To address this issue, fisetin (FT), a natural phytochemical with poor solubility, is stabilized using silk sericin (SS) to create a composite (SS/FT). The therapeutic potential of the SS/FT on ulcerative colitis is extensively investigated, and the results showed that it effectively alleviated the body weight loss and colon length shortening induced by dextran sulfate sodium. Notably, SS/FT downregulated the immune response, decreased colonic histopathological lesions, and reduced the cGAS/STING signal activation. This suggests that SS/FT may offer a promising therapy for treating ulcerative colitis.

Encapsulation of Sericin-Decorated Efficient Agents in Silk Hydrogels for Wound Dressings

Excessive oxidative stress, bacterial infections, and inflammation are the primary factors impeding the healing of skin wounds. Bioactive hydrogels are commonly employed in the treatment of skin injuries. However, the limited solubility of many drugs and active agents in water significantly hampers their effectiveness in hydrogel dressings. In this research, prior to incorporation into the silk fibroin (SF) hydrogel matrix, two active agents curcumin and silver nanoparticles (Ag NPs) were decorated by silk sericin to improve their dispersibility and stability in water. The resultant SF/Ag/C hydrogels combined the biological safety and nontoxicity of SF, the antioxidant and anti-inflammatory efficacy of curcumin, and the antibacterial effect of Ag NPs. These properties effectively enhanced wound repair by reducing bacterial infections, mitigating oxidative stress, suppressing the expression of pro-inflammatory factors, and promoting angiogenesis. This study presented a straightforward approach for constructing bioactive hydrogels for the promotion of the wound healing process.

Sericin from Fibroin-Deficient Silkworms Served as a Promising Resource for Biomedicine

Sericin, a fascinating natural biomaterial derived from silkworms, has received increasing interest in recent years for its unique bioactivity and high compatibility. Silkworms can be divided into wild-type or silk fibroin-deficient mutants according to whether they synthesize and secrete silk fibroin. Silk fibroin-deficient mutant silkworms and their cocoons are convenient for us to obtain diverse and high-quality sericin, which has been applicated in various fields such as cell culture, tissue engineering, drug delivery, and cosmetics. Here, we present an overview of our silkworm varieties resources, especially silk fibroin-deficient mutant silkworms. We optimized various extraction methods of sericin and summarized the characteristics and advantages of sericin. Finally, we developed and discussed a series of sericin-based biomaterials for promising applications for a diverse set of needs.

Regulatory effect of sericin protein in inflammatory pathways; A comprehensive review

Sericin protein is a type of protein derived from silk cocoons. Sericin hydrogen bonds cause adhesion to the silk cocoon. This substance contains a large amount of serine amino acids in its structure. At first, the medicinal properties of this substance were unknown, but today many properties have been discovered for this substance. The unique properties of this substance have made it widely used in the pharmaceutical and cosmetic industries. The applications of Sericin in pharmacy are as follows. Sericin is used to repair wounds by producing collagen. Other uses for the drug include anti-diabetic, anti-cholesterol, metabolic modulator, anti-tumor, heart protection, antioxidant, antibacterial, wound healing, cell proliferation, UV protection, freezing, and skin moisturizing. The physicochemical properties of Sericin have attracted the attention of pharmacists and their widespread use in the production of drugs and treatment of diseases. One of the critical and unique properties of Sericin is its anti-inflammatory property. In this article, this property of Sericin is discussed in detail, and according to the experiments performed by pharmacists, this substance has shown a significant effect in eliminating inflammation. This study aimed to evaluate the impact of Sericin protein in relieving inflammation.

Silk sericin alleviates aberrant photoperiod-induced alterations in testicular and adrenal steroidogenesis in adult mice

BACKGROUND

Steroidogenesis is a complex process of sequential enzymatic reactions affected by climate change. Animals respond to altered day length, the so-called photoperiod, with changes in physiology. The study aimed to an evaluation of sericin effect in alleviating steroidogenesis disorders induced by disturbed photoperiod in mice.

METHODS

The animals were randomly divided into three groups according to the lighting cycle: a control group with a standard 12_Light:12_Dark cycle, a short-term photoperiod group with a 6_Light:18_Dark cycle, and a long-term photoperiod group with an 18_Light:6_Dark cycle. Both short and long-term groups were subdivided into two equal subgroups: The placebo and the sericin-treated subgroups received, for five weeks from prepubertal throughout adulthood, one intraperitoneal injection per week of the solvent and 1 g sericin/kg body weight, respectively.

RESULTS

Selected oxidative stress parameters and testicular and adrenal steroidogenic capacities of adult mice were measured. After five weeks, the placebo group with impaired photoperiod showed a decrease in the quality and quantity of sperm and a reduction in testosterone, corticosterone, aldosterone, total antioxidant capacity, xanthine oxidase, and melatonin. At the same time, in these groups, there was an increase in the level of aromatase, malondialdehyde, cholesterol, and steroidogenic factor-1 (SF-1) expression in the adrenal cortex and an enhancement in histological lesions. Mice receiving sericin had parameters similar to the control group.

CONCLUSION

Our findings reveal that silk sericin can reduce the stress caused by photoperiod disorders regarding testicular function, sex hormone levels, and sperm quantity and quality. Thus, sericin is a biocompatible protein with a promising potential for its use in the case of organisms living under an abnormal photoperiod.

Silk Sericin: A Promising Sustainable Biomaterial for Biomedical and Pharmaceutical Applications

Silk is a natural composite fiber composed mainly of hydrophobic fibroin and hydrophilic sericin, produced by the silkworm Bombyx mori. In the textile industry, the cocoons of B. mori are processed into silk fabric, where the sericin is substantially removed and usually discarded in wastewater. This wastewater pollutes the environment and water sources. However, sericin has been recognized as a potential biomaterial due to its biocompatibility, immunocompatibility, biodegradability, anti-inflammatory, antibacterial, antioxidant and photoprotective properties. Moreover, sericin can produce hydrogels, films, sponges, foams, dressings, particles, fibers, etc., for various biomedical and pharmaceutical applications (e.g., tissue engineering, wound healing, drug delivery, cosmetics). Given the severe environmental pollution caused by the disposal of sericin and its beneficial properties, there has been growing interest in upcycling this biomaterial, which could have a strong and positive economic, social and environmental impact.

Study of the Antioxidative Effects of Bombyx mori Silk Sericin in Cultures of Murine Retinal Photoreceptor Cells

The availability of natural substances able to fulfill the role of antioxidants in a physiologic environment is important for the development of therapies against diseases associated with excessive production of reactive oxygen species and ensuing oxidative stress. Antioxidant properties have been reported episodically for sericin, a proteinaceous constituent of the silk thread in the cocoons generated by the larvae of the Lepidoptera order. We investigated the sericin fractions isolated from the cocoons spun by the domesticated (Bombyx mori) silkworm. Three fractions were isolated and evaluated, including two peptidoid fractions, the crude sericin and the purified (dialyzed) sericin, and the non-peptidoid methanolic extract of the crude fraction. When subjected to Trolox equivalent antioxidant capacity (TEAC) assay, the extract showed much higher antioxidant capacity as compared to the crude or purified sericin fractions. The three fractions were also evaluated in cultures of murine retinal photoreceptor cells (661 W), a cell line that is highly susceptible to oxidants and is crucially involved in the retinopathies primarily caused by oxidative stress. The extract displayed a significant dose-dependent protective effect on the cultured cells exposed to hydrogen peroxide. In identical conditions, the crude sericin showed a certain level of antioxidative activity at a higher concentration, while the purified sericin did not show any activity. We concluded that the non-peptidoid components accompanying sericin were chiefly responsible for the previously reported antioxidant capacity associated with sericin fractions, a conclusion supported by the qualitative detection of flavonoids in the extract but not in the purified sericin fraction.

Biotechnological and Technical Challenges Related to Cultured Meat Production

The constant growth of the population has pushed researchers to find novel protein sources. A possible solution to this problem has been found in cellular agriculture, specifically in the production of cultured meat. In the following review, the key steps for the production of in vitro meat are identified, as well as the most important challenges. The main biological and technical approaches are taken into account and discussed, such as the choice of animal, animal-free alternatives to fetal bovine serum (FBS), cell biomaterial interactions, and the implementation of scalable and sustainable biofabrication and culturing systems. In the light of the findings, as promising as cultured meat production is, most of the discussed challenges are in an initial stage. Hence, research must overcome these challenges to ensure efficient large-scale production.

Effect of sericin, a silk derived protein, on the amplification of Zika virus in insect and mammalian cell cultures

Sericin, a silk-derived non-immunogenic protein, has been used to improve cell culture performance by increasing viability, cell concentration, and promoting adherence of several cell lines. Here, we hypothesized that the properties of sericin can enhance the amplification of flaviviruses in cell cultures. The propagation of flavivirus is inefficient and limits scientific research. Zika virus (ZIKV) is an important human pathogen that has been widely studied because of its high impact on public health. There is a need to amplify Zika virus both for research and vaccine development. In this work, we show that sericin improves ZIKV amplification in insect (C6/36) and mammalian (Vero) cell cultures, and that it has a cryoprotectant capacity. Supplementation of cell culture media with sericin at 80 µg/mL resulted in a significant increase of 1 log in the concentration of ZIKV infectious particles produced from both cell lines. Furthermore, final virus yields increased between 5 and 10-fold in Vero cells and between 7 and 23-fold in C6/36 cells when sericin was supplemented, compared to control conditions. These results show that sericin is an effective supplement to increase ZIKV production by Vero and C6/36 cells. Additionally, sericin was a suitable cryoprotective agent, and hence an alternative to FBS and DMSO, for the cryopreservation of C6/36 cells but not for Vero cells.

Sericin-chitosan-glycosaminoglycans hydrogels incorporated with growth factors for in vitro and in vivo skin repair

Globally, skin repair costs billion dollars per annum. Diversified matrices are fabricated to address this important area of healthcare. Most common limitations associated with them are the inflated production cost and insufficient functional repair. Our work explores the fabrication and potential utilization of Antheraea mylitta silk protein sericin (possessing inherent anti-bacterial and antioxidant properties) based hydrogels for skin tissue. The integrity of the hydrogels is achieved by combining sericin, chitosan (provide anti-bacterial and structural support), and glycosaminoglycans (component of biologically formed extracellular matrix). The hydrogels are functionalized by incorporation of vascular endothelial growth factor and transforming growth factor-β. They exhibit enhanced cellular functions in terms of their growth, production of matrix metalloproteinase, and collagen along with the recovery of impairment and the reconstruction of the lost dermal tissue. The in vivo biocompatibility analyses reveal that sericin-containing hydrogels promote the repair of skin tissue, angiogenesis, and illicit minimal immune response. These unique hydrogels mimicking the naturally occurring skin tissue and imparting additional beneficial features provide an appropriate physical environment and biological cues for the promotion of skin tissue repair.

Augmented Therapeutic Efficacy of Naringenin Through Microemulsion-Loaded Sericin Gel Against UVB-Induced Photoaging

Naringenin (NAR) is a flavonoid found in citrus fruits such as grapes and oranges. Recently, NAR has demonstrated its potential in inhibition of photoaging. The aim of the present study was to investigate the efficacy of sericin (SR) gel loaded with NAR microemulsion (ME) to inhibit UVB-induced photoaging and prevention of epidermoid carcinoma in animal model. NAR -ME was prepared and optimized through Box-Behnken design. The optimized ME was loaded into sericin (SR) gel. The formulations were subjected to various in vitro, in vivo and cytotoxicity studies over A431 cell lines. The optimized ME revealed a globule size of 249.05 ± 3.78 nm, 6.7 ± 0.5 pH and 73.1 ± 2.11% release over a period of 24 h respectively. Cytotoxicity studies revealed a depression in IC₅₀ value in NAR -ME (65.11 ± 1.54 μg/ml) when compared with NAR (118.1 ± 2.09 μg/ml). The NAR-ME-SR gel displayed enhanced therapeutic potential when compared with plain NAR, in terms of augmented antiproliferative activity. Graphical abstract.