Weak SARS-CoV-2-specific responses of TIGIT-expressing CD8 + T cells in people living with HIV after a third dose of a SARS-CoV-2 inactivated vaccine / 中华医学杂志(英文版)

BACKGROUND@#T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT), an inhibitory receptor expressed on T cells, plays a dysfunctional role in antiviral infection and antitumor activity. However, it is unknown whether TIGIT expression on T cells influences the immunological effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inactivated vaccines.@*METHODS@#Forty-five people living with HIV (PLWH) on antiretroviral therapy (ART) for more than two years and 31 healthy controls (HCs), all received a third dose of a SARS-CoV-2 inactivated vaccine, were enrolled in this study. The amounts, activation, proportion of cell subsets, and magnitude of the SARS-CoV-2-specific immune response of TIGIT + CD4 + and TIGIT + CD8 + T cells were investigated before the third dose but 6 months after the second vaccine dose (0W), 4 weeks (4W) and 12 weeks (12W) after the third dose.@*RESULTS@#Compared to that in HCs, the frequency of TIGIT + CD8 + T cells in the peripheral blood of PLWH increased at 12W after the third dose of the inactivated vaccine, and the immune activation of TIGIT + CD8 + T cells also increased. A decrease in the ratio of both T naïve (T N ) and central memory (T CM ) cells among TIGIT + CD8 + T cells and an increase in the ratio of the effector memory (T EM ) subpopulation were observed at 12W in PLWH. Interestingly, particularly at 12W, a higher proportion of TIGIT + CD8 + T cells expressing CD137 and CD69 simultaneously was observed in HCs than in PLWH based on the activation-induced marker assay. Compared with 0W, SARS-CoV-2-specific TIGIT + CD8 + T-cell responses in PLWH were not enhanced at 12W but were enhanced in HCs. Additionally, at all time points, the SARS-CoV-2-specific responses of TIGIT + CD8 + T cells in PLWH were significantly weaker than those of TIGIT - CD8 + T cells. However, in HCs, the difference in the SARS-CoV-2-specific responses induced between TIGIT + CD8 + T cells and TIGIT - CD8 + T cells was insignificant at 4W and 12W, except at 0W.@*CONCLUSIONS@#TIGIT expression on CD8 + T cells may hinder the T-cell immune response to a booster dose of an inactivated SARS-CoV-2 vaccine, suggesting weakened resistance to SARS-CoV-2 infection, especially in PLWH. Furthermore, TIGIT may be used as a potential target to increase the production of SARS-CoV-2-specific CD8 + T cells, thereby enhancing the effectiveness of vaccination.

Targeted elimination of mutant mitochondrial DNA in MELAS-iPSCs by mitoTALENs

Mitochondrial diseases are maternally inherited heterogeneous disorders that are primarily caused by mitochondrial DNA (mtDNA) mutations. Depending on the ratio of mutant to wild-type mtDNA, known as heteroplasmy, mitochondrial defects can result in a wide spectrum of clinical manifestations. Mitochondria-targeted endonucleases provide an alternative avenue for treating mitochondrial disorders via targeted destruction of the mutant mtDNA and induction of heteroplasmic shifting. Here, we generated mitochondrial disease patient-specific induced pluripotent stem cells (MiPSCs) that harbored a high proportion of m.3243A>G mtDNA mutations and caused mitochondrial encephalomyopathy and stroke-like episodes (MELAS). We engineered mitochondrial-targeted transcription activator-like effector nucleases (mitoTALENs) and successfully eliminated the m.3243A>G mutation in MiPSCs. Off-target mutagenesis was not detected in the targeted MiPSC clones. Utilizing a dual fluorescence iPSC reporter cell line expressing a 3243G mutant mtDNA sequence in the nuclear genome, mitoTALENs displayed a significantly limited ability to target the nuclear genome compared with nuclear-localized TALENs. Moreover, genetically rescued MiPSCs displayed normal mitochondrial respiration and energy production. Moreover, neuronal progenitor cells differentiated from the rescued MiPSCs also demonstrated normal metabolic profiles. Furthermore, we successfully achieved reduction in the human m.3243A>G mtDNA mutation in porcine oocytes via injection of mitoTALEN mRNA. Our study shows the great potential for using mitoTALENs for specific targeting of mutant mtDNA both in iPSCs and mammalian oocytes, which not only provides a new avenue for studying mitochondrial biology and disease but also suggests a potential therapeutic approach for the treatment of mitochondrial disease, as well as the prevention of germline transmission of mutant mtDNA.

Innervation of the chick embryo cornea during development / 中华实验眼科杂志

Background To understand the distribution and development of corneal nerve in animal or human has an important significance for clinical and basic research of corneal diseases.At present,some studies on cornea nerve development and location have been performed.However,the quantified study on innervation and distribution of corneal nerve fibers as embryonic development has not been reported.Objective This study attempted to understand the distribution of corneal nerve fibers in the development of chick embryo,and to evaluate the changes of the length and density of corneal nerve fibers with aging of chick embryo.Methods Whole chick corneas with limbus were obtained from chick embryo aged 6-20 days (E6-E20),and corneal nerve fiber was labeled using immunofluorescence technique by anti-neuron-specific β-Ⅲ tubulin antibody.The corneas were radially cut into 4 parts,and the integrate corneal flat mounts were prepared with the upward epithelium and mounting with anti-fade fluorescent quenching buffer glycerin containing DAPI.Fluorescence microscope was used to capture the nerve fiber images in cornea,and cornea area and the number of nerve fiber bundles were exhibited by using Photoshop CS4.Cornea nerve fiber density and total length were measured by Imaris x64 7.4.2 software.Results Total cornea flat mounts showed that the nerve bundles grew from temporal scleral forward cornea limbus at E6-E8,and the nerve fibers formed the ring surrounding by limbus during E9-E10.Then the fibers extended forward the central cornea in E11 to E15 and developed into nerve fiber plexus on the whole cornea in E16 to E20.During the period of E6-E20,the corneal surface area,the length and density of corneal nerve fibers were gradually increased with the aging of chick embryo,showing statistically significant differences among different time points (F =127.007,227.051,67.748,all at P＜0.01).The increase of the corneal area of the chick embryo presented a strong positive correlation with the extending of length of the corneal nerve fiber (r =0.863,P＜0.01).Chick corneal nerve fiber bundle appeared at E13,with a number of (59.00 ± 1.14)/mm2 and then increased to a peak of (576.75 ±29.16)/mm2 at E 18 and reduced to (299.67± 25.46)/mm2 at E20,with a significant difference among them (F =13.759,P=0.000).Conclusions Corneal nerve starts to develop in E9 of chick embryo,and the corneal surface area,the total length of the corneal nerve fibers and the density rapidly increase concurrently with the development of chick embryo.