Collagen is a major structural protein in the matrix of animal cells and the most widely distributed and abundant functional protein in mammals. Collagen’s good biocompatibility, biodegradability and biological activity make it a very valuable biomaterial. According to the source of collagen, it can be broadly categorized into two types: one is animal collagen; the other is recombinant collagen. Animal collagen is mainly extracted and purified from animal connective tissues by chemical methods, such as acid, alkali and enzyme methods, etc. Recombinant collagen refers to collagen produced by gene splicing technology, where the amino acid sequence is first designed and improved according to one’s own needs, and the gene sequence of improved recombinant collagen is highly consistent with that of human beings, and then the designed gene sequence is cloned into the appropriate vector, and then transferred to the appropriate expression vector. The designed gene sequence is cloned into a suitable vector, and then transferred to a suitable expression system for full expression, and finally the target protein is obtained by extraction and purification technology. Recombinant collagen has excellent histocompatibility and water solubility, can be directly absorbed by the human body and participate in the construction of collagen, remodeling of the extracellular matrix, cell growth, wound healing and site filling, etc., which has demonstrated significant effects, and has become the focus of the development of modern biomedical materials. This paper firstly elaborates the structure, type, and tissue distribution of human collagen, as well as the associated genetic diseases of different types of collagen, then introduces the specific process of producing animal source collagen and recombinant collagen, explains the advantages of recombinant collagen production method, and then introduces the various systems of expressing recombinant collagen, as well as their advantages and disadvantages, and finally briefly introduces the application of animal collagen, focusing on the use of animal collagen in the development of biopharmaceutical materials. In terms of application, it focuses on the use of animal disease models exploring the application effects of recombinant collagen in wound hemostasis, wound repair, corneal therapy, female pelvic floor dysfunction (FPFD), vaginal atrophy (VA) and vaginal dryness, thin endometritis (TE), chronic endometritis (CE), bone tissue regeneration in vivo, cardiovascular diseases, breast cancer (BC) and anti-aging. The mechanism of action of recombinant collagen in the treatment of FPFD and CE was introduced, and the clinical application and curative effect of recombinant collagen in skin burn, skin wound, dermatitis, acne and menopausal urogenital syndrome (GSM) were summarized. From the exploratory studies and clinical applications, it is evident that recombinant collagen has demonstrated surprising effects in the treatment of all types of diseases, such as reducing inflammation, promoting cell proliferation, migration and adhesion, increasing collagen deposition, and remodeling the extracellular matrix. At the end of the review, the challenges faced by recombinant collagen are summarized: to develop new recombinant collagen types and dosage forms, to explore the mechanism of action of recombinant collagen, and to provide an outlook for the future development and application of recombinant collagen.

OBJECTIVE To explore the pharmacokinetic characteristics of 3 blood-absorbed components of Xiangshao sanjie oral liquid in rats with hyperplasia of mammary gland （HMG）. METHODS Female SD rats were divided into control group and HMG group according to body weight， with 6 rats in each group. The HMG group was given estrogen+progesterone to construct HMG model. After modeling， two groups were given 1.485 g/kg of Xiangshao sanjie oral liquid （calculated by crude drug） intragastrically， once a day， for 7 consecutive days. Blood samples were collected before the first administration （0 h）， and at 5， 15， 30 minutes and 1， 2， 4， 8， 12， 24 hours after the last administration， respectively. Using chlorzoxazone as the internal standard， the plasma concentrations of ferulic acid， paeoniflorin and rosmarinic acid in rats were detected by UPLC-Q/TOF-MS. The pharmacokinetic parameters [area under the drug time curve （AUC0－24 h， AUC0－∞）， mean residence time （MRT0－∞）， half-life （t1/2）， peak time （tmax）， peak concentration （cmax）] were calculated by the non-atrioventricular model using Phoenix WinNonlin 8.1 software. RESULTS Compared with the control group， the AUC0－24 h， AUC0－∞ and cmax of ferulic acid in the HMG group were significantly increased （P＜0.05）； the AUC0－24 h， AUC0－∞ ， MRT0－∞ ， t1/2 and cmax of paeoniflorin increased， but there was no significant difference between 2 groups （P＞0.05）； the AUC0－24 h and MRT0-∞ of rosmarinic acid were significantly increased or prolonged （P＜0.05）. C ONCLUSIONS In HMG model rats， the exposure of ferulic acid， paeoniflorin and rosmarinic acid in Xiangshao sanjie oral liquid all increase， and the retention time of rosmarinic acid is significantly prolonged.

OBJECTIVE To analyze the clinical characteristics of aplastic anemia （AA）/pure red cell aplasia （PRCA） induced by pembrolizumab， and provide reference for clinical safe drug use. METHODS Using search terms as “pembrolizumab”， “keytruda”， “anemia” and “aplastic anemia” in both Chinese and English， the literature related to AA/PRCA induced by pembrolizumab were retrieved from PubMed， Embase， CNKI， Wanfang and VIP databases， and then analyzed descriptively and statistically. RESULTS A total of 10 patients were included from 10 literature； among these 10 patients， there were 5 males and 5 females， with 5 patients being aged 65 or above. The primary disease was mainly metastatic melanoma （4 cases）. AA/PRCA occurred 13 d-3 years after the first dose of pembrolizumab. The main clinical manifestations included fatigue， dyspnea， oral/nasal bleeding， diffuse purpura， etc.； 8 cases developed moderate anemia and 2 cases developed severe anemia. After discontinuation and receiving supportive therapy， 5 cases improved， 1 case worsened in anemia， and 4 cases died. CONCLUSIONS When using pembrolizumab in clinical practice， blood routine should be regularly monitored. When AA/PRCA and other related symptoms occur， pembrolizumab should be stopped in time and a therapy regimen should be formulated according to the patient’ condition， to ensure the safety of medication.

The innate immune system can be boosted in response to subsequent triggers by pre-exposure to microbes or microbial products, known as “trained immunity”. Compared to classical immune memory, innate trained immunity has several different features. Firstly, the molecules involved in trained immunity differ from those involved in classical immune memory. Innate trained immunity mainly involves innate immune cells (e.g., myeloid immune cells, natural killer cells, innate lymphoid cells) and their effector molecules (e.g., pattern recognition receptor (PRR), various cytokines), as well as some kinds of non-immune cells (e.g., microglial cells). Secondly, the increased responsiveness to secondary stimuli during innate trained immunity is not specific to a particular pathogen, but influences epigenetic reprogramming in the cell through signaling pathways, leading to the sustained changes in genes transcriptional process, which ultimately affects cellular physiology without permanent genetic changes (e.g., mutations or recombination). Finally, innate trained immunity relies on an altered functional state of innate immune cells that could persist for weeks to months after initial stimulus removal. An appropriate inducer could induce trained immunity in innate lymphocytes, such as exogenous stimulants (including vaccines) and endogenous stimulants, which was firstly discovered in bone marrow derived immune cells. However, mature bone marrow derived immune cells are short-lived cells, that may not be able to transmit memory phenotypes to their offspring and provide long-term protection. Therefore, trained immunity is more likely to be relied on long-lived cells, such as epithelial stem cells, mesenchymal stromal cells and non-immune cells such as fibroblasts. Epigenetic reprogramming is one of the key molecular mechanisms that induces trained immunity, including DNA modifications, non-coding RNAs, histone modifications and chromatin remodeling. In addition to epigenetic reprogramming, different cellular metabolic pathways are involved in the regulation of innate trained immunity, including aerobic glycolysis, glutamine catabolism, cholesterol metabolism and fatty acid synthesis, through a series of intracellular cascade responses triggered by the recognition of PRR specific ligands. In the view of evolutionary, trained immunity is beneficial in enhancing protection against secondary infections with an induction in the evolutionary protective process against infections. Therefore, innate trained immunity plays an important role in therapy against diseases such as tumors and infections, which has signature therapeutic effects in these diseases. In organ transplantation, trained immunity has been associated with acute rejection, which prolongs the survival of allografts. However, trained immunity is not always protective but pathological in some cases, and dysregulated trained immunity contributes to the development of inflammatory and autoimmune diseases. Trained immunity provides a novel form of immune memory, but when inappropriately activated, may lead to an attack on tissues, causing autoinflammation. In autoimmune diseases such as rheumatoid arthritis and atherosclerosis, trained immunity may lead to enhance inflammation and tissue lesion in diseased regions. In Alzheimer’s disease and Parkinson’s disease, trained immunity may lead to over-activation of microglial cells, triggering neuroinflammation even nerve injury. This paper summarizes the basis and mechanisms of innate trained immunity, including the different cell types involved, the impacts on diseases and the effects as a therapeutic strategy to provide novel ideas for different diseases.

Objectives: Hypoparathyroidism (HP) is a rare endocrine disorder caused by parathyroid hormone (PTH) defi ciency. The PTH is a candidate gene for familial isolated hypoparathyroidism (FIH). This study aimed to investigate the pathogenicity of two novel rare variants (RVs) ofPTH through in vitro functional study. Methods: Targeted next-generation sequencing was used to identify candidate gene mutations. Clinical data were retrospectively collected. Wild-type (WT) PTH was used as a template for site-directed mutagenesis to create mutant eukaryotic expression plasmids, which were transfected into cells. Treated with or without 4-phenylbu tyric acid (4-PBA), the levels of intact PTH (iPTH) and PTH (1-84) were measured by chemiluminescence, and protein expression was assessed using Western blotting. Results: Two patients carrying PTH mutations (c.154G > A: p.Val52Ile, c.270G > T: p.Leu90Phe) were identified.Patient 1, a 45-year-old male, presented with carpal and pedal numbness, muscle cramps, and low serum calcium (1.29 mmol/L). Patient 2, a 12-year-old female, had muscle twitches, convulsions, low calcium (1.50 mmol/L), and iPTH of 4 pg/mL. The iPTH or PTH (1-84) levels in the medium transfected with mutant Val52Ile and Leu90Phe PTH decreased by 31%–38%, and 51%–96% compared to WT (allP < 0.05), which were not rescued by 4-PBA. No significant changes in intracellular PTH expression were observed. Conclusions In this study, two novel RVs of PTH(Val52Ile and Leu90Phe) were identified that may impair hormone synthesis and secretion. Our study has broadened the mutation spectrum of the PTH and shed light on potential mechanisms underlying FIH.

Background: s/Aims: Sarcomatoid hepatocellular carcinoma (HCC) is a rare histological subtype of HCC characterized by extremely poor prognosis; however, its molecular characterization has not been elucidated. Methods: In this study, we conducted an integrated multiomics study of whole-exome sequencing, RNA-seq, spatial transcriptome, and immunohistochemical analyses of 28 paired sarcomatoid tumor components and conventional HCC components from 10 patients with sarcomatoid HCC, in order to identify frequently altered genes, infer the tumor subclonal architectures, track the genomic evolution, and delineate the transcriptional characteristics of sarcomatoid HCCs. Results: Our results showed that the sarcomatoid HCCs had poor prognosis. The sarcomatoid tumor components and the conventional HCC components were derived from common ancestors, mostly accessing similar mutational processes. Clonal phylogenies demonstrated branched tumor evolution during sarcomatoid HCC development and progression. TP53 mutation commonly occurred at tumor initiation, whereas ARID2 mutation often occurred later. Transcriptome analyses revealed the epithelial–mesenchymal transition (EMT) and hypoxic phenotype in sarcomatoid tumor components, which were confirmed by immunohistochemical staining. Moreover, we identified ARID2 mutations in 70% (7/10) of patients with sarcomatoid HCC but only 1–5% of patients with non-sarcomatoid HCC. Biofunctional investigations revealed that inactivating mutation of ARID2 contributes to HCC growth and metastasis and induces EMT in a hypoxic microenvironment. Conclusions We offer a comprehensive description of the molecular basis for sarcomatoid HCC, and identify genomic alteration (ARID2 mutation) together with the tumor microenvironment (hypoxic microenvironment), that may contribute to the formation of the sarcomatoid tumor component through EMT, leading to sarcomatoid HCC development and progression.

Objectives: Hypoparathyroidism (HP) is a rare endocrine disorder caused by parathyroid hormone (PTH) defi ciency. The PTH is a candidate gene for familial isolated hypoparathyroidism (FIH). This study aimed to investigate the pathogenicity of two novel rare variants (RVs) ofPTH through in vitro functional study. Methods: Targeted next-generation sequencing was used to identify candidate gene mutations. Clinical data were retrospectively collected. Wild-type (WT) PTH was used as a template for site-directed mutagenesis to create mutant eukaryotic expression plasmids, which were transfected into cells. Treated with or without 4-phenylbu tyric acid (4-PBA), the levels of intact PTH (iPTH) and PTH (1-84) were measured by chemiluminescence, and protein expression was assessed using Western blotting. Results: Two patients carrying PTH mutations (c.154G > A: p.Val52Ile, c.270G > T: p.Leu90Phe) were identified.Patient 1, a 45-year-old male, presented with carpal and pedal numbness, muscle cramps, and low serum calcium (1.29 mmol/L). Patient 2, a 12-year-old female, had muscle twitches, convulsions, low calcium (1.50 mmol/L), and iPTH of 4 pg/mL. The iPTH or PTH (1-84) levels in the medium transfected with mutant Val52Ile and Leu90Phe PTH decreased by 31%–38%, and 51%–96% compared to WT (allP < 0.05), which were not rescued by 4-PBA. No significant changes in intracellular PTH expression were observed. Conclusions In this study, two novel RVs of PTH(Val52Ile and Leu90Phe) were identified that may impair hormone synthesis and secretion. Our study has broadened the mutation spectrum of the PTH and shed light on potential mechanisms underlying FIH.

Objectives: Hypoparathyroidism (HP) is a rare endocrine disorder caused by parathyroid hormone (PTH) defi ciency. The PTH is a candidate gene for familial isolated hypoparathyroidism (FIH). This study aimed to investigate the pathogenicity of two novel rare variants (RVs) ofPTH through in vitro functional study. Methods: Targeted next-generation sequencing was used to identify candidate gene mutations. Clinical data were retrospectively collected. Wild-type (WT) PTH was used as a template for site-directed mutagenesis to create mutant eukaryotic expression plasmids, which were transfected into cells. Treated with or without 4-phenylbu tyric acid (4-PBA), the levels of intact PTH (iPTH) and PTH (1-84) were measured by chemiluminescence, and protein expression was assessed using Western blotting. Results: Two patients carrying PTH mutations (c.154G > A: p.Val52Ile, c.270G > T: p.Leu90Phe) were identified.Patient 1, a 45-year-old male, presented with carpal and pedal numbness, muscle cramps, and low serum calcium (1.29 mmol/L). Patient 2, a 12-year-old female, had muscle twitches, convulsions, low calcium (1.50 mmol/L), and iPTH of 4 pg/mL. The iPTH or PTH (1-84) levels in the medium transfected with mutant Val52Ile and Leu90Phe PTH decreased by 31%–38%, and 51%–96% compared to WT (allP < 0.05), which were not rescued by 4-PBA. No significant changes in intracellular PTH expression were observed. Conclusions In this study, two novel RVs of PTH(Val52Ile and Leu90Phe) were identified that may impair hormone synthesis and secretion. Our study has broadened the mutation spectrum of the PTH and shed light on potential mechanisms underlying FIH.

Background: s/Aims: Sarcomatoid hepatocellular carcinoma (HCC) is a rare histological subtype of HCC characterized by extremely poor prognosis; however, its molecular characterization has not been elucidated. Methods: In this study, we conducted an integrated multiomics study of whole-exome sequencing, RNA-seq, spatial transcriptome, and immunohistochemical analyses of 28 paired sarcomatoid tumor components and conventional HCC components from 10 patients with sarcomatoid HCC, in order to identify frequently altered genes, infer the tumor subclonal architectures, track the genomic evolution, and delineate the transcriptional characteristics of sarcomatoid HCCs. Results: Our results showed that the sarcomatoid HCCs had poor prognosis. The sarcomatoid tumor components and the conventional HCC components were derived from common ancestors, mostly accessing similar mutational processes. Clonal phylogenies demonstrated branched tumor evolution during sarcomatoid HCC development and progression. TP53 mutation commonly occurred at tumor initiation, whereas ARID2 mutation often occurred later. Transcriptome analyses revealed the epithelial–mesenchymal transition (EMT) and hypoxic phenotype in sarcomatoid tumor components, which were confirmed by immunohistochemical staining. Moreover, we identified ARID2 mutations in 70% (7/10) of patients with sarcomatoid HCC but only 1–5% of patients with non-sarcomatoid HCC. Biofunctional investigations revealed that inactivating mutation of ARID2 contributes to HCC growth and metastasis and induces EMT in a hypoxic microenvironment. Conclusions We offer a comprehensive description of the molecular basis for sarcomatoid HCC, and identify genomic alteration (ARID2 mutation) together with the tumor microenvironment (hypoxic microenvironment), that may contribute to the formation of the sarcomatoid tumor component through EMT, leading to sarcomatoid HCC development and progression.

Objectives: Hypoparathyroidism (HP) is a rare endocrine disorder caused by parathyroid hormone (PTH) defi ciency. The PTH is a candidate gene for familial isolated hypoparathyroidism (FIH). This study aimed to investigate the pathogenicity of two novel rare variants (RVs) ofPTH through in vitro functional study. Methods: Targeted next-generation sequencing was used to identify candidate gene mutations. Clinical data were retrospectively collected. Wild-type (WT) PTH was used as a template for site-directed mutagenesis to create mutant eukaryotic expression plasmids, which were transfected into cells. Treated with or without 4-phenylbu tyric acid (4-PBA), the levels of intact PTH (iPTH) and PTH (1-84) were measured by chemiluminescence, and protein expression was assessed using Western blotting. Results: Two patients carrying PTH mutations (c.154G > A: p.Val52Ile, c.270G > T: p.Leu90Phe) were identified.Patient 1, a 45-year-old male, presented with carpal and pedal numbness, muscle cramps, and low serum calcium (1.29 mmol/L). Patient 2, a 12-year-old female, had muscle twitches, convulsions, low calcium (1.50 mmol/L), and iPTH of 4 pg/mL. The iPTH or PTH (1-84) levels in the medium transfected with mutant Val52Ile and Leu90Phe PTH decreased by 31%–38%, and 51%–96% compared to WT (allP < 0.05), which were not rescued by 4-PBA. No significant changes in intracellular PTH expression were observed. Conclusions In this study, two novel RVs of PTH(Val52Ile and Leu90Phe) were identified that may impair hormone synthesis and secretion. Our study has broadened the mutation spectrum of the PTH and shed light on potential mechanisms underlying FIH.