Antigenicity of tissues and organs from GGTA1/CMAH/β4GalNT2 triple gene knockout pigs

Clinical xenotransplantations have been hampered by human preformed antibody-mediated damage of the xenografts.To overcome biological incompatibility between pigs and humans,one strategy is to remove the major antigens[Gal,Neu5 Gc,and Sd(a)]present on pig cells and tissues.Triple gene(GGTAI,CMAH,and β4 GalNT2)knockout(TKO)pigs were produced in our laboratory by CRISPR-Cas9 targeting.To investigate the antigenicity reduction in the TKO pigs,the expression levels of these three xenoantigens in the cornea,heart,liver,spleen,lung,kidney,and pancreas tissues were examined.The level of human IgG/IgM binding to those tissues was also investigated,with wildtype pig tissues as control.The results showed that aGal,Neu5 Gc,and Sd(a)were markedly positive in all the examined tissues in wildtype pigs but barely detected in TKO pigs.Compared to wildtype pigs,the liver,spleen,and pancreas of TKO pigs showed comparable levels of human IgG and IgM binding,whereas corneas,heart,lung,and kidney of TKO pigs exhibited significantly reduced human IgG and IgM binding.These results indicate that the antigenicity of TKO pig is significantly reduced and the remaining xenoantigens on porcine tissues can be eliminated via a gene targeting approach.

Protective effects on acute hypoxic-ischemic brain damage in mfat-1 transgenic mice by alleviating neuroinflammation

Acute hypoxic-ischemic brain damage(HIBD)mainly occurs in adults as a result of perioperative cardiac arrest and asphyxia.The benefits of n-3 polyunsaturated fatty acids(n-3 PUFAs)in maintaining brain growth and development are well documented.However,possible protective targets and underlying mechanisms of mfat-1 mice on HIBD require further investigation.The mfat-1 transgenic mice exhibited protective effects on HIBD,as indicated by reduced infarct range and improved neurobehavioral defects.RNA-seq analysis showed that multiple pathways and targets were involved in this process,with the anti-inflammatory pathway as the most significant.This study has shown for the first time that mfat-1 has protective effects on HIBD in mice.Activation of a G protein-coupled receptor 120(GPR120)-related anti-inflammatory pathway may be associated with perioperative and postoperative complications,thus innovating clinical intervention strategy may potentially benefit patients with HIBD.

OSBPL2-disrupted pigs recapitulate dual features of human hearing loss and hypercholesterolaemia

Oxysterol binding protein like 2(OSBPL2), an important regulator in cellular lipid metabolism and transport, was identified as a novel deafness-causal gene in our previous work. To resemble the phenotypic features of OSBPL2 mutation in animal models and elucidate the potential genotypephenotype associations, the OSBPL2-disrupted Bama miniature(BM) pig model was constructed using CRISPR/Cas9-mediated gene editing, somatic cell nuclear transfer(SCNT) and embryo transplantation approaches, and then subjected to phenotypic characterization of auditory function and serum lipid profiles. The OSBPL2-disrupted pigs displayed progressive hearing loss(HL) with degeneration/apoptosis of cochlea hair cells(HCs) and morphological abnormalities in HC stereocilia, as well as hypercholesterolaemia. High-fat diet(HFD) feeding aggravated the development of HL and led to more severe hypercholesterolaemia. The dual phenotypes of progressive HL and hypercholesterolaemia resembled in OSBPL2-disrupted pigs confirmed the implication of OSBPL2 mutation in nonsydromic hearing loss(NSHL) and contributed to the potential linkage between auditory dysfunction and dyslipidaemia/hypercholesterolaemia.

A Bama miniature pig model of monoallelic TSC1 mutation for human tuberous sclerosis complex

Tuberous sclerosis complex(TSC)is a dominant genetic neurocutaneous syndrome characterized by multiple organ hamartomas.Although rodent models bearing a germline mutation in either TSC1 or TSC2 gene have been generated,they do not develop pathogenic lesions matching those seen in patients with TSC because of the significant differences between mice and humans,highlighting the need for an improved large animal model of TSC.Here,we successfully generate monoallelic TSC1-modified Bama miniature pigs using the CRISPR/Cas9 system along with somatic cell nuclear transfer(SCNT)technology.The expression of phosphorylated target ribosomal protein S6 is significantly enhanced in the piglets,indicating that disruption of a TSC1 allele activate the mechanistic target of rapamycin(mTOR)signaling pathway.Notably,differing from the mouse TSC models reported previously,the TSC1^(+/−)Bama miniature pig developed cardiac rhabdomyoma and subependymal nodules,resembling the major clinical features that occur in patients with TSC.These TSC1^(+/−)Bama miniature pigs could serve as valuable large animal models for further elucidation of the pathogenesis of TSC and the development of therapeutic strategies for TSC disease.

Overexpressing dominant-negative FGFR2-IIIb impedes lung branching morphogenesis in pigs

Genetic studies with mouse models have shown that fibroblast growth factor receptor 2-Ⅲb（FGFR2-Ⅲb）plays crucial roles in lung development and differentiation. To evaluate the effect of FGFR2-Ⅲb in pig lung development, we employed somatic cell nuclear transfer（SCNT） technology to generate transgenic pig fetuses overexpressing the transmembrane（dn FGFR2-Ⅲb-Tm） and soluble（dn FGFR2-Ⅲb-HFc） forms of the dominant-negative human FGFR2-Ⅲb driven by the human surfactant protein C（SP-C） promoter,which was specifically expressed in lung epithelia. Eight dn FGFR2-Ⅲb-Tm transgenic and twelve dn FGFR2-Ⅲb-HFc transgenic pig fetuses were collected from three and two recipient sows, respectively.Repression of FGFR2-Ⅲb in lung epithelia resulted in smaller lobes and retardation of alveolarization in both forms of dn FGFR2-Ⅲb transgenic fetuses. Moreover, the dn FGFR2-Ⅲb-HFc transgenic ones showed more deterioration in lung development. Our results demonstrate that disruption of FGFR2-Ⅲb signaling in the epithelium impedes normal branching and alveolarization in pig lungs, which is less severe than the results observed in transgenic mice. The dn FGFR2-Ⅲb transgenic pig is a good model for the studies of blastocyst complementation as well as the mechanisms of lung development and organogenesis.

Factors in?uencing the somatic cell nuclear transfer ef?ciency in pigs

Using a data set from our laboratory, we assessed the effects of several factors on pig cloning ef?ciency. The results demonstrated that cells at high con?uence( > 90%) used as donor cell resulted in higher pregnancy rate, delivery rate and overall cloning ef?ciency(number of live offspring born per reconstructed embryo transferred to recipients) compared with the cells at 60% to79% con?uence and 80% to 89% con?uence. Cells with four, ?ve and six passages compromised the pregnancy and delivery rates compared with ?rst passage cells. The number of blastocysts transferred by somatic cell nuclear transfer(SCNT) did not signi?cantly affect the cloning ef?ciency, but transfer of blastocyst derived from in vitro culture 5 d after SCNT achieved a signi?cantly higher pregnancy rate compared with one to two cell SCNT embryos from overnight culture. The highest pregnancy rate, delivery rate and the largest litter size were obtained when Bama Miniature pig ?broblasts were used as donor cells and Landrace/Yorkshire hybrid gilts were used as recipients. Recipients treated with chemicals for estrus synchronization had higher pregnancy rates compared with untreated recipients. Our data might be helpful for improving SCNT ef?ciency in pigs.

Erratum to“A Bama miniature pig model of monoallelic TSC1 mutation for human tuberous sclerosis complex”[Journal of Genetics and Genomics(2020)47,735–742]

This erratum clarifies information in the article“A Bama miniature pig model of monoallelic TSC1 mutation for human tuberous sclerosis complex”by Li et al.(2020).In the“Acknowledgment”section,the statement that“This work was supported by grants from the National Natural Science Foundation of China(31701283,81970164)”should say“This work was supported by grants from the National Natural Science Foundation of China(81874144,81970164)”.