Qiong-Qiong Wei

Sericin, a natural macromolecular protein and the main component of silkworm cocoons, exhibits biocompatibility, excellent mechanical properties, and biodegradability. Previous research has confirmed that the sericin protein possesses anticancer properties. Gastric cancer (GC) poses a serious hazard to human health, with a low rate of early diagnosis and a poor prognosis. Investigating the safety and effectiveness of drugs for their used in treatment is imperative. In this study, we confirmed that Antherea pernyi sericin (APS) inhibited the proliferation, migration, and clonal formation of GC cells and caused apoptosis in the cells by regulating the expression of Bcl2 and Bax. Moreover, our data show that APS did not exhibit significant toxicity in normal gastric mucosal cells and mice. Furthermore, the results show that APS suppressed the proliferation of cisplatin-resistant GC cells and promoted cellular apoptosis; however, it had no synergistic effects with cisplatin. All the results indicated that APS exhibits antitumor activity against GC and is a prospective medicinal agent for the clinical treatment of GC, with minimal toxicity and adverse side effects. This research can provide a theoretical basis for sericin in the field of tumor treatment, especially for the application of natural macromolecular polypeptide drugs.

Baculoviruses, the largest studied insect viruses, are highly pathogenic to host insects. Bombyx mori nucleopolyhedrovirus (BmNPV) is the main cause of nuclear polyhedrosis of silkworm, a viral disease that causes significant economic losses to the sericulture industry. The anti-BmNPV mechanism of the silkworm has not yet been characterized. Carboxypeptidase is an enzyme that is involved in virtually all life activities of animals and plants. Studies have shown that the carboxypeptidase family is related to insect immunity. There are few reports on the role of carboxypeptidase in the defense of silkworms against pathogen invasion. In this study, we identified the homologous gene Bombyx mori metal carboxypeptidases12 (BmMCP12) related to mammalian carboxypeptidase A2 (CPA2) and found that BmMCP12 had a Zn-pept domain. The BmMCP12 gene was primarily located in the cytoplasm and was highly expressed in the midgut of silkworms, and the expression level in BmN-SWU1 cells was upregulated after infection with BmNPV. After overexpression of the BmMCP12 gene, quantitative real-time (qRT)-PCR and Western blots showed that BmMCP12 could inhibit BmNPV replication, whereas knockout of the gene had the opposite effect. In addition, we constructed transgenic silkworm strains with a knockout of BmMCP12, and the transgenic strains had reduced resistance to BmNPV. These findings deepen the functional study of silkworm carboxypeptidase and provide a new target for BmNPV disease prevention in silkworms.

Temperature is an important factor in the growth, development, survival, and reproduction of organisms. The high-temperature resistance mechanism of insects may be significant for use in the prevention and control of insect pests. The silkworm, Bombyx mori, is an important Lepidoptera model species for studies on pest control in agriculture and forestry. We identified a gene in B. mori, the B. mori singed (Bmsn) gene, which is involved in the high-temperature resistance of silkworms. Sn proteins are highly conserved among species in many taxonomic groups. The overexpression of the Bmsn gene promoted the proliferation of silkworm cells, reduced oxidation, and reduced the accumulation of reactive oxygen species under stress. Interfering with the Bmsn gene had the opposite result. We constructed a transgenic B. mori strain that overexpressed the Bmsn gene. The physiological traits of the transgenic strain were significantly improved, and it had stronger high-temperature resistance. The Bmsn gene is involved in the process by which fat bodies respond to high-temperature stress. These findings provide insights into the mechanism of high-temperature resistance of insects and offer a new perspective on agricultural and forestry pest control.