Partially knocking out NtPDK1a/1b/1c/1d simultaneously in Nicotiana tabacum using CRISPR/CAS9 technology results in auxin-related developmental defects.

The eukaryotic AGC protein kinase subfamily (protein kinase A/ protein kinase G/ protein kinase C-family) is involved in regulating numerous biological processes across kingdoms, including growth and development, and apoptosis. PDK1(3-phosphoinositide-dependent protein kinase 1) is a conserved serine/threonine kinase in eukaryotes, which is both a member of AGC kinase and a major regulator of many other downstream AGC protein kinase family members. Although extensively investigated in model plant Arabidopsis, detailed reports for tobacco PDK1s have been limited. To better understand the functions of PDK1s in tobacco, CRISPR/CAS9 transgenic lines were generated in tetraploid N. tabacum, cv. Samsun (NN) with 5-7 of the 8 copies of 4 homologous PDK1 genes in tobacco genome (NtPDK1a/1b/1c/1d homologs) simultaneously knocked out. Numerous developmental defects were observed in these NtPDK1a/1b/1c/1d CRISPR/CAS9 lines, including cotyledon fusion leaf shrinkage, uneven distribution of leaf veins, convex veins, root growth retardation, and reduced fertility, all of which reminiscence of impaired polar auxin transport. The severity of these defects was correlated with the number of knocked out alleles of NtPDK1a/1b/1c/1d. Consistent with the observation in Arabidopsis, it was found that the polar auxin transport, and not auxin biosynthesis, was significantly compromised in these knockout lines compared with the wild type tobacco plants. The fact that no homozygous plant with all 8 NtPDK1a/1b/1c/1d alleles being knocked out suggested that knocking out 8 alleles of NtPDK1a/1b/1c/1d could be lethal. In conclusion, our results indicated that NtPDK1s are versatile AGC kinases that participate in regulation of tobacco growth and development via modulating polar auxin transport. Our results also indicated that CRISPR/CAS9 technology is a powerful tool in resolving gene redundancy in polyploidy plants.

Knocking out NtSARD1a/1b/1c/1d by CRISPR/CAS9 technology reduces the biosynthesis of salicylic acid (SA) and compromises immunity in tetraploid Nicotiana tabacum.

Salicylic acid (SA) is a key phyto-hormone that is essential for plant immunity. SARD1 (SYSTEMIC ACQUIRED RESISTANCE DEFICIENT 1), a member of the CBP60 (CALMODULIN-BINDING PROTEIN60) gene family, is one of the major transcription factors regulating the expression of the genes in SA biosynthesis. SARD1 has been extensively studied in model plant Arabidopsis. However, the function of SARD1 homologues in SA biosynthesis and immune responses have rarely been investigated in other plant species. In this study, the CRISPR/CAS9 (Clustered Regularly Interspersed Short Palindromic Repeats/CAS9) technology was used in creating transgenic tobacco mutant lines with 6-8 alleles of four NtSARD1 homologous genes (NtSARD1a/1b/1c/1d) knocked out. No significant difference in morphological phenotype was observed between the transgenic knockout lines and the wild type tobacco plants, indicating that knocking out NtSARD1s does not affect the growth and development in tobacco. However, knocking out or partially knocking out of NtSARD1a/b/c/d resulted in a significantly reduced expression of NtICS1, the key gene in SA biosynthesis pathway, and thus the subsequently decreased SA/SAG accumulations in response to Pst DC3000 (Pseudomonas syrangae pv.tomato DC3000) infection, indicating a key role of NtSARD1 genes in SA biosynthesis in tobacco. As a consequence of reduced SA/SAG accumulation, the Pst DC3000-induced expression of NtPR genes as well as the resistance to Pst DC3000 were both significantly reduced in these knockout lines compared with the wild type tobacco plants. Interestingly, the reductions in the SA/SAG level, NtPR gene induction and Pst DC3000 resistance were positively correlated with the number of alleles being knocked out. Furthermore, LUC reporter gene driven by the promoter of NtICS1 containing two G(A/T)AATT(T/G) motifs could be activated by NtSARD1a, suggesting that NtSARD1a could bind to the core G(A/T)AATT(T/G) motifs and thus activate the expression of LUC reporter. Taken together, our results demonstrated that the NtSARD1 proteins play essential roles in SA biosynthesis and immune responses in tobacco. Our results also demonstrated that the CRISPR/CAS9 technology can overcome gene redundancy and is a powerful tool to study gene functions in polyploid plant species.

Multi-center investigation of the clinical and pathological characteristics of inflammatory breast cancer based on Chinese Society of Breast Surgery (CSBrs-007).

BACKGROUND: Inflammatory breast cancer (IBC) is an aggressive type of cancer with poor prognosis and outcomes. This study aimed to investigate clinicopathological features, molecular characteristics, and treatments among Chinese patients diagnosed with IBC. METHODS: We collected data of 95 patients with IBC who were treated by members of the Chinese Society of Breast Surgery, from January 2017 to December 2018. The data, including demographic characteristics, pathological findings, surgical methods, systemic treatment plans, and follow-up, were obtained using a uniform electronic questionnaire. The clinicopathological features of different molecular types in patients without distant metastases were compared using the Kruskal-Wallis (H) test followed by post hoc analyses. RESULTS: Lymph node metastasis was noted in 75.8% of all patients, while distant metastasis was noted in 21.4%. Pathological findings indicated invasive ductal and lobular carcinomas in 86.8% and 5.3% of cases, respectively. Hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) (41.5%) and HR-/HER2+ (20.1%) were the most common biologic subtypes, followed by HR+/HER2+ (19.1%) and HR-/HER2- (19.1%). Stage III IBC was treated via pre-operative neoadjuvant chemotherapy in 87.7% of the cases, predominantly using anthracycline and taxanes. A total of 91.9% of patients underwent surgical treatment. Among them, 77.0% of the patients underwent modified radical mastectomy, 8.1% of whom also underwent immediate breast reconstruction. The Kruskal-Wallis test revealed that the efficacy of chemotherapy significantly differed among those with HR+/HER2- and HR-/HER2- tumors (adjusted P = 0.008), and Ki-67 expression significantly differed in HR-/HER2+ and HR+/HER2+ molecular subtypes (adjusted P = 0.008). CONCLUSION: Our study provides novel insight into clinicopathological characteristics and treatment status among patients with IBC in China, and might provide a direction and basis for further studies. TRIAL REGISTRATION: chictr.org.cn, No. ChiCTR1900027179; http://www.chictr.org.cn/showprojen.aspx?proj=45030.

GJA8 missense mutation disrupts hemichannels and induces cell apoptosis in human lens epithelial cells.

Autosomal dominant congenital cataract (ADCC), the most common hereditary disease, is a major cause of eye disease in children. Due to its high genetic and clinical heterogeneity, the identification of ADCC-associated gene mutations is essential for the development of molecular therapies. In this study, we examined a four-generation Chinese pedigree with ADCC and identified putative mutations in ADCC candidate genes via next-generation sequencing (NGS) followed by Sanger sequencing. A novel missense mutation in GJA8 (c.T217C) in ADCC patients causes a serine-to-proline substitution at residue 73 of connexin 50 (Cx50); no mutation was found in unaffected family members and unrelated healthy individuals. Functional analysis revealed that this missense mutation disrupts protein function in human lens epithelial cells (HLEpiCs), which fails to form calcium-sensitive hemichannels. Furthermore, mutant Cx50 leads to decreased ROS scavenging by inhibiting G6PD expression and thus induces cell apoptosis via aberrant activation of the unfolded protein response (UPR). In conclusion, we report a novel GJA8 heterozygous mutation in a Chinese family with a vital role in ADCC, broadening the genetic spectrum of this disease.

Two novel mutations identified in ADCC families impair crystallin protein distribution and induce apoptosis in human lens epithelial cells.

Congenital cataract (CC) is a clinical and genetically heterogeneous eye disease that primarily causes lens disorder and even amblyopic blindness in children. As the mechanism underlying CC is genetically inherited, identification of CC-associated gene mutations and their role in protein distribution are topics of both pharmacological and biological research. Through physical and ophthalmic examinations, two Chinese pedigrees with autosomal dominant congenital cataract (ADCC) were recruited for this study. Mutation analyses of CC candidate genes by next-generation sequencing (NGS) and Sanger sequencing revealed a novel missense mutation in CRYBB2 (p.V146L) and a deletion mutation in CRYAA (p.116_118del). Both mutations fully co-segregated were not observed in unaffected family members or in 100 unrelated healthy controls. The CRYBB2 missense mutation disrupts the distribution of CRYBB2 in human lens epithelial cells (HLEpiCs), and the CRYAA deletion mutation causes hyperdispersion of CRYAA. Furthermore, these two crystallin mutations result in aberrant expression of unfolded protein response (UPR) marker genes as well as apoptosis in HLEpiCs. Collectively, these findings broaden the genetic spectrum of ADCC.

Surgical treatment and visual outcomes of cataract with persistent hyperplastic primary vitreous.

AIM: To evaluate the surgical treatment and visual outcomes of eyes with cataract and persistent hyperplastic primary vitreous (PHPV). METHODS: This retrospective study included patients with cataract and PHPV treated with various strategies. Anterior PHPV was treated using phacoemulsification with underwater electric coagulation on posterior capsule neovascularization, posterior capsulotomy, anterior vitrectomy, and intraocular lens (IOL) implantation. Posterior PHPV was treated with lensectomy, posterior vitrectomy, retinal photocoagulation, and IOL implantation or silicone oil tamponade. Visual acuity (VA), pattern visual evoked potential (P-VEP), anatomic recovery, postoperative complications, and amblyopia outcome were examined. Subjects were followed-up for 3-48mo after surgery. RESULTS: Of the 30 patients (33 eyes) with congenital cataract and PHPV included (average age, 39.30±35.47mo), 9 eyes had anterior PHPV and 24 had posterior PHPV. Thirty-two eyes were surgically treated. Eyes with anterior PHPV received an IOL during one-stage (6 eyes) and two-stage (3 eyes) implantation. Postoperative complications included retinal detachment (1 eye) and recurrent anterior chamber hemorrhage (1 eye). In eyes with posterior PHPV, 6 and 11 eyes received IOLs in one- and two-stage procedures, respectively. Silicone oil was retained in 2 eyes, and IOLs were not implanted in 4 eyes. VA significantly improved in 25 eyes following operations and 3-48mo of amblyopia treatment. P-VEP P100 was improved following surgery in both PHPV types. CONCLUSION: Our surgical strategies are appropriate and effective for anterior and posterior PHPV. Early surgical intervention and amblyopia therapy result in positive treatment outcomes.