Large-scale production of functional human lysozyme in transgenic cloned goats

Psidium guajava L.- dichloromethane and ethyl acetate fractions ameliorate striped catfish (Pangasianodon hypophthalmus) status via immune response, inflammatory, and apoptosis pathways

Psidium guajava L. is known to possess immune-modulatory properties in humans and other mammals. Although the positive effects of P. guajava-based diets on the immunological status have been shown for some fish species, the underlying molecular mechanisms of its protective effects remain to be investigated. The aims of this study were to evaluate the immune-modulatory effects of two guava fractions from dichloromethane (CC) and ethyl acetate (EA) on striped catfish with in vitro and in vivo experiments. Striped catfish head kidney leukocytes were stimulated with 40, 20, 10 and 0 μg/ml of each extract fraction, and the immune parameters (ROS, NOS, and lysozyme) were examined at 6 and 24h post stimulation. A final concentration of each fraction at 40, 10 and 0 μg/fish was then intraperitoneally injected into the fish. After 6, 24, and 72h of administration, immune parameters as well as the expression of some cytokines related to innate and adaptive immune responses, inflammation, and apoptosis were measured in the head kidney. Results indicated that the humoral (lysozyme) and cellular (ROS and NOS) immune endpoints were regulated differently by CC and EA fractions depending on dose and time in both, in vitro and in vivo experiments. With regards to the in vivo experiment, the CC fraction of the guava extract could significantly enhance the TLRs-MyD88-NF-κB signaling pathway by upregulating its cytokine genes (tlr1, tlr4, myd88, and traf6), following the upregulation of inflammatory (nfκb, tnf, il1β, and il6) and apoptosis (tp53 and casp8) genes 6 h after injection. Moreover, fish treated with both CC and EA fractions significantly enhanced cytokine gene expression including lys and inos at the later time points - 24h or 72h. Our observations suggest that P. guajava fractions modulate the immune, inflammatory, and apoptotic pathways.

Recent Insights Into the Prognostic and Therapeutic Applications of Lysozymes

Lysozymes are naturally occurring enzymes present in a variety of biological organisms, such as bacteria, fungi, and animal bodily secretions and tissues. It is also the main ingredient of many ethnomedicines. It is well known that lysozymes and lysozyme-like enzymes can be used as anti-bacterial agents by degrading bacterial cell wall peptidoglycan that leads to cell death, and can also inhibit fungi, yeasts, and viruses. In addition to its direct antimicrobial activity, lysozyme is also an important component of the innate immune system in most mammals. Increasing evidence has shown the immune-modulatory effects of lysozymes against infection and inflammation. More recently, studies have revealed the anti-cancer activities of lysozyme in multiple types of tumors, potentially through its immune-modulatory activities. In this review, we summarized the major functions and underlying mechanisms of lysozymes derived from animal and plant sources. We highlighted the therapeutic applications and recent advances of lysozymes in cancers, hypertension, and viral diseases, aiming toseeking alternative therapies for standard medical treatment bypassing side effects. We also evaluated the role of lysozyme as a promising cancer marker for prognosis to indicate the outcomes recurrence for patients.

Restoring mammary gland structures and functions with autogenous cell therapy

In somatic cell reprogramming, cells must escape the somatic cell-specific gene expression program to adopt other cell fates. Here, in vitro chemical induction with RepSox generated chemically induced mammary epithelial cells (CiMECs) with milk secreting functions from goat ear fibroblasts (GEFs). Transplanted CiMECs regenerated the normal mammary gland structure with milk-secreting functions in nude mice. Single-cell RNA sequencing revealed that during the reprogramming process, GEFs may sequentially undergo embryonic ectoderm (EE)-like and different MEC developmental states and finally achieve milk secreting functions, bypassing the pluripotent state. Mechanistically, Smad3 upregulation induced by transforming growth factor β (TGFβ) receptor 1 (TGFβR1) downregulation led to GEF reprogramming into CiMECs without other reprogramming factors. The TGFβR1-Smad3 regulatory effects will provide new insight into the TGFβ signaling pathway regulation of somatic cell reprogramming. These findings suggest an innovative strategy for autogenous cell therapy for mammary gland defects and the production of transgenic mammary gland bioreactors.

An Event-Specific Real-Time PCR Method for Measuring Transgenic Lysozyme Goat Content in Trace Samples

Lysozymes are used in sterilisation, antisepsis, dairy additives, inflammation, and cancer. One transgenic goat line expressing high levels of human lysozyme (hLZ) in goat milk has been developed in China. Herein, we established an event-specific real-time polymerase chain reaction (real-time PCR) method to detect the transgenic hLZ goat line. The developed method has high specificity, sensitivity and accuracy, and a wide quantitative dynamic range. The limit of detection and limit of quantification was 5 and 10 copies per reaction, respectively. The practical sample analysis results showed that the method could identify and quantify transgenic lysozyme content in trace samples in routine lab analyses. Furthermore, the potential applicability in risk assessment, such as molecular characterisation and gene horizontal transfer, was confirmed. We believe that this method is suitable for the detection of transgenic hLZ goat line and its derivate.

In vivo modification of the goat mammary gland glycosylation pathway

Complex recombinant glycoproteins produced as potential biopharmaceuticals in goat's milk have an aberrant pattern of N-glycosylation due to the lack of multi-antennary structures. Overexpression of glycosyltransferases may increase oligosaccharide branching of the desired glycoproteins. Here, human erythropoietin fused to human IgG Fc (EPO-Fc) was co-expressed with N-acetyl-glucosaminyltransferase-IVa (GnT-IVa) by adenoviral transduction in goat mammary gland to evaluate the in vivo modification of N-glycosylation pattern in this tissue. Adenoviral vectors, containing the EPO-Fc and GnT-IVa sequences were assembled for in vitro and in vivo expression in mammalian cell culture or in goat mammary gland. Protein detection was assessed by gel electrophoresis and western blot, and N-glycans were identified by HPLC and mass spectrometry. GnT-IVa overexpression and its colocalization with EPO-Fc in the Golgi apparatus of SiHa cells were demonstrated. N-glycan analysis of in vitro and in vivo expression of EPO-Fc modified by GnT-IVa (EPO-Fc/GnT-IVa) showed an increase in high molecular weight structures, which corresponded to tri- and tetra-antennary N-glycans in SiHa cells and mostly tri-antennary N-glycans in goat's milk from transformed mammary tissue. The results confirmed that successful modification of the goat mammary gland secretion pathway could be achieved by co-expressing glycoenzymes together with the glycoprotein of interest. This is the first report of modification of the N-glycosylation pattern in the goat mammary gland in vivo, and constitutes a step forward for improving the use of the mammary gland as a bioreactor for the production of complex recombinant proteins.

Sheep and Goat Genome Engineering: From Random Transgenesis to the CRISPR Era

Sheep and goats are valuable livestock species that have been raised for their production of meat, milk, fiber, and other by-products. Due to their suitable size, short gestation period, and abundant secretion of milk, sheep and goats have become important model animals in agricultural, pharmaceutical, and biomedical research. Genome engineering has been widely applied to sheep and goat research. Pronuclear injection and somatic cell nuclear transfer represent the two primary procedures for the generation of genetically modified sheep and goats. Further assisted tools have emerged to enhance the efficiency of genetic modification and to simplify the generation of genetically modified founders. These tools include sperm-mediated gene transfer, viral vectors, RNA interference, recombinases, transposons, and endonucleases. Of these tools, the four classes of site-specific endonucleases (meganucleases, ZFNs, TALENs, and CRISPRs) have attracted wide attention due to their DNA double-strand break-inducing role, which enable desired DNA modifications based on the stimulation of native cellular DNA repair mechanisms. Currently, CRISPR systems dominate the field of genome editing. Gene-edited sheep and goats, generated using these tools, provide valuable models for investigations on gene functions, improving animal breeding, producing pharmaceuticals in milk, improving animal disease resistance, recapitulating human diseases, and providing hosts for the growth of human organs. In addition, more promising derivative tools of CRISPR systems have emerged such as base editors which enable the induction of single-base alterations without any requirements for homology-directed repair or DNA donor. These precise editors are helpful for revealing desirable phenotypes and correcting genetic diseases controlled by single bases. This review highlights the advances of genome engineering in sheep and goats over the past four decades with particular emphasis on the application of CRISPR/Cas9 systems.

In vivo nonspecific immunomodulatory and antispasmodic effects of common purslane (Portulaca oleracea Linn.) leaf extracts in ICR mice

ETHNOPHARMACOLOGICAL RELEVANCE

Portulaca oleracea (common purslane) is used in traditional medicine to cure various illnesses. However, its immune-protective properties and antispasmodic effects still need more pharmacological data if the plant will be utilized in herbal and drug formulations. Therefore, the present study determined the capacity of this plant species to modulate nonspecific immune responses and to confirm its antispasmodic activity in vivo in ICR mice.

MATERIALS AND METHODS

Phagocytic activity of peritoneal macrophage, splenic lymphocyte proliferation and plasma lysozyme levels were measured in mice that were immunosuppressed using cyclophosphamide and treated with the ethyl acetate extract of Portulaca oleracea. In addition, the charcoal meal transit test was used to measure intestinal motility using ethanolic (EtOH), hexane (HEX), and ethyl acetate (EA) solvent extracts. Phytochemical analysis was undertaken and DPPH scavenging properties of the three solvent extracts were also determined.

RESULTS

The EA extract of P. oleracea exhibited immunoactivity through significant increase in phagocytosis and higher proliferative response in splenic lymphocytes. Plasma lysozyme level was also higher in EA-treated mice at high dose but this was not statistically significant. Decreased intestinal motility was also exhibited in mice treated with the three leaf solvent extracts compared to the negative control and the acetylcholine-treated group. The antispasmodic activity of the solvent extracts was comparable to that of the atropine-treated group. Phytochemical analysis showed the presence of tannins in EA extract in addition to alkaloids and steroids. The EtOH and HEX extracts contain alkaloids, steroids and terpenoids. DPPH scavenging activity was highest in the EA extract.

CONCLUSIONS

The present study showed that the EA extract of P. oleracea leaves ameliorated the immunosuppressive action of cyclophosphamide in mice. The results also indicated that the three solvent extracts of the plant decreased smooth muscle spasms in mice ileum. However, further experiments are warranted to further isolate the plant's immunoactive component. Also, the mechanisms involved in the immunoactivity and antispasmodic properties of P. oleracea deserve full elucidation.

Human lactoferrin efficiently targeted into caprine beta-lactoglobulin locus with transcription activator-like effector nucleases

Objective

To create genetically modified goat as a biopharming source of recombinant human lacotoferrin (hLF) with transcription activator-like effector nucleases.

Methods

TALENs and targeting vector were transferred into cultured fibroblasts to insert hLF cDNA in the goat beta-lactoglobulin (BLG) locus with homology-directed repair. The gene targeted efficiency was checked using sequencing and TE7I assay. The bi-allelic gene targeted colonies were isolated and confirmed with polymerase chain reaction, and used as donor cells for somatic cell nuclear transfer (SCNT).

Results

The targeted efficiency for BLG gene was approximately 10%. Among 12 Bi-allelic gene targeted colonies, five were used in first round SCNT and 4 recipients (23%) were confirmed pregnant at 30 d. In second round SCNT, 7 (53%), 4 (31%), and 3 (23%) recipients were confirmed to be pregnant by ultrasound on 30 d, 60 d, and 90 d.

Conclusion

This finding signifies the combined use of TALENs and SCNT can generate bi-allelic knock-in fibroblasts that can be cloned in a fetus. Therefore, it might lay the foundation for transgenic hLF goat generation and possible use of their mammary gland as a bioreactor for large-scale production of recombinant hLF.

Expression of recombinant human lysozyme in transgenic chicken promotes the growth of Bifidobacterium in the intestine and improves postnatal growth of chicken

Lysozyme is one kind of antimicrobial proteins and often used as feed additive which can defend against pathogenic bacteria and enhance immune function of animals. In this study, we have injected the lentiviral vector expressing recombinant human lysozyme (rhLZ) gene into the blastoderm of chicken embryo to investigate the effect of recombinant human lysozyme on postnatal intestinal microbiota distribution and growth performance of chicken. Successfully, we generated 194 transgenic chickens identified by Southern blot with a positive transgenic rate of 24%. The average concentration of rhLZ was 29.90 ± 6.50 μg/mL in the egg white. Lysozyme in egg white of transgenic chickens had a significantly higher antibacterial activity than those of non-transgenic chickens by lysoplate assay (P < 0.05). The feces of transgenic and non-transgenic chickens were collected and five types of bacteria (Lactobacillus, Salmonella, Bifidobacterium, Staphylococcus aureus and Escherichia coli) were isolated and cultured to detect the impact of rhLZ on gut microbiota. Among the five bacteria, the number of Bifidobacterium in the intestine of those transgenic was significantly increased (P < 0.05). Moreover, the growth traits of the transgenic and non-transgenic chickens were analyzed. It was found that the 6-week shank length, 6-week weight and 18-week weight of transgenic chickens were significantly increased than that of non-transgenic chickens. The results demonstrated that rhLZ-transgenic chicken could promote the growth of Bifidobacterium in the intestine and improve the postnatal growth of chicken.

Expression of Active Fluorophore Proteins in the Milk of Transgenic Pigs Bypassing the Secretory Pathway

We describe the expression of recombinant fluorescent proteins in the milk of two lines of transgenic pigs generated by Sleeping Beauty transposon-mediated genetic engineering. The Sleeping Beauty transposon consisted of an ubiquitously active CAGGS promoter driving a fluorophore cDNA, encoding either Venus or mCherry. Importantly, the fluorophore cDNAs did not encode for a signal peptide for the secretory pathway, and in previous studies of the transgenic animals a cytoplasmic localization of the fluorophore proteins was found. Unexpectedly, milk samples from lactating sows contained high levels of bioactive Venus or mCherry fluorophores. A detailed analysis suggested that exfoliated cells of the mammary epithelium carried the recombinant proteins passively into the milk. This is the first description of reporter fluorophore expression in the milk of livestock, and the findings may contribute to the development of an alternative concept for the production of bioactive recombinant proteins in the udder.

Large-scale production of functional human lysozyme from marker-free transgenic cloned cows

Human lysozyme is an important natural non-specific immune protein that is highly expressed in breast milk and participates in the immune response of infants against bacterial and viral infections. Considering the medicinal value and market demand for human lysozyme, an animal model for large-scale production of recombinant human lysozyme (rhLZ) is needed. In this study, we generated transgenic cloned cows with the marker-free vector pBAC-hLF-hLZ, which was shown to efficiently express rhLZ in cow milk. Seven transgenic cloned cows, identified by polymerase chain reaction, Southern blot, and western blot analyses, produced rhLZ in milk at concentrations of up to 3149.19 ± 24.80 mg/L. The purified rhLZ had a similar molecular weight and enzymatic activity as wild-type human lysozyme possessed the same C-terminal and N-terminal amino acid sequences. The preliminary results from the milk yield and milk compositions from a naturally lactating transgenic cloned cow 0906 were also tested. These results provide a solid foundation for the large-scale production of rhLZ in the future.

The transgenic animal platform for biopharmaceutical production

The recombinant production of therapeutic proteins for human diseases is currently the largest source of innovation in the pharmaceutical industry. The market growth has been the driving force on efforts for the development of new therapeutic proteins, in which transgenesis emerges as key component. The use of the transgenic animal platform offers attractive possibilities, residing on the low production costs allied to high productivity and quality of the recombinant proteins. Although many strategies have evolved over the past decades for the generation of transgenic founders, transgenesis in livestock animals generally faces some challenges, mainly due to random transgene integration and control over transgene copy number. But new developments in gene editing with CRISPR/Cas system promises to revolutionize the field for its simplicity and high efficiency. In addition, for the final approval of any given recombinant protein for animal or human use, the production and characterization of bioreactor founders and expression patterns and functionality of the proteins are technical part of the process, which also requires regulatory and administrative decisions, with a large emphasis on biosafety. The approval of two mammary gland-derived recombinant proteins for commercial and clinical use has boosted the interest for more efficient, safer and economic ways to generate transgenic founders to meet the increasing demand for biomedical proteins worldwide.

Recent advances for the production and recovery methods of lysozyme

Lysozyme is an antimicrobial peptide with a high enzymatic activity and positive charges. Therefore, it has applications in food and pharmaceutical industries as an antimicrobial agent. Lysozyme is ubiquitous in both animal and plant kingdoms. Currently, egg-white lysozyme is the most commercially available form of lysozyme. The main concerns of egg-white lysozyme are high recovery cost, low activity and most importantly the immunological problems to some people. Therefore, human lysozyme production has gained importance in recent years. Scientists have developed transgenic plants, animals and microorganisms that can produce human lysozyme. Out of these, microbial production has advantages for commercial productions, because high production levels are achievable in a relatively short time. It has been reported that fermentation parameters, such as pH, temperature, aeration, are key factors to increase the effectiveness of the human lysozyme production. Moreover, purification of the lysozyme from the fermentation broth needs to be optimized for the economical production. In conclusion, this review paper covers the mechanism of lysozyme, its sources, production methods and recovery of lysozyme.

Construction and in vivo evaluation of a mammary gland-specific expression vector for human lysozyme

A mammary gland-specific expression vector p205C3 was constructed with the 5'- and 3'-flanking regions of β-lactoglobulin gene and the first intron of β-casein gene of Chinese dairy goat as regulatory sequences. Human lysozyme (hLYZ) cDNA from mammary gland was cloned into p205C3 and the recombinant vector was used to generate transgenic mice by microinjection. Based on the lysoplate assay, four female offspring of one male founder were detected expressing recombinant hLYZ in their milk at the levels of 5-200 mg/l, and the expressed protein had the same molecular weight as that of normal hLYZ. Besides mammary glands, ectopic expressions were also found in the spleens and the small intestines of the transgenic mice. Among the offspring, the female transgenic mice maintained and expressed the transgene stably with a highest expression level of 750 mg/l. Therefore, p205C3 could be used to develop animal mammary gland bioreactors expressing hLYZ.