Identification and structural characterization of a mutant KRAS-G12V specific TCR restricted by HLA-A3.

Mutations in KRAS are some of the most common across multiple cancer types and are thus attractive targets for therapy. Recent studies demonstrated that mutant KRAS generates immunogenic neoantigens that are targetable by adoptive T-cell therapy in metastatic diseases. To expand mutant KRAS-specific immunotherapies, it is critical to identify additional HLA-I allotypes that can present KRAS neoantigens and their cognate T-cell receptors (TCR). Here, we identified a murine TCR specific to a KRAS-G12V neoantigen (7VVVGAVGVGK16) using a vaccination approach with transgenic mice expressing HLA-A*03:01 (HLA-A3). This TCR demonstrated exquisite specificity for mutant G12V and not WT KRAS peptides. To investigate the molecular basis for neoantigen recognition by this TCR, we determined its structure in complex with HLA-A3(G12V). G12V-TCR CDR3ß and CDR1ß formed a hydrophobic pocket to interact with p6 Val of the G12V but not the WT KRAS peptide. To improve the tumor sensitivity of this TCR, we designed rational substitutions to improve TCR:HLA-A3 contacts. Two substitutions exhibited modest improvements in TCR binding avidity to HLA-A3 (G12V) but did not sufficiently improve T-cell sensitivity for further clinical development. Our study provides mechanistic insight into how TCRs detect neoantigens and reveals the challenges in targeting KRAS-G12V mutations.

A method of genetic transformation and gene editing of succulents without tissue culture.

Succulents, valued for their drought tolerance and ornamental appeal, are important in the floriculture market. However, only a handful of succulent species can be genetically transformed, making it difficult to improve these plants through genetic engineering. In this study, we adapted the recently developed cut-dip-budding (CDB) gene delivery system to transform three previously recalcitrant succulent varieties - the dicotyledonous Kalanchoe blossfeldiana and Crassula arborescens and the monocotyledonous Sansevieria trifasciata. Capitalizing on the robust ability of cut leaves to regenerate shoots, these plants were successfully transformed by directly infecting cut leaf segments with the Agrobacterium rhizogenes strain K599. The transformation efficiencies were approximately 74%, 5% and 3.9%-7.8%, respectively, for K. blossfeldiana and C. arborescens and S. trifasciata. Using this modified CDB method to deliver the CRISPR/Cas9 construct, gene editing efficiency in K. blossfeldiana at the PDS locus was approximately 70%. Our findings suggest that succulents with shoot regeneration ability from cut leaves can be genetically transformed using the CDB method, thus opening up an avenue for genetic engineering of these plants.

The knowledge, attitudes, and practices of arteriovenous access assessment among hemodialysis nurses: A multicenter cross-sectional survey.

INTRODUCTION: Hemodialysis nurses' cannulation technique, monitoring, and management methods can affect patients' vascular access longevity. An arteriovenous access assessment comprises a medical history and vascular assessment through physical examination and surveillance. However, further exploration is needed to fully understand hemodialysis nurses' knowledge, attitudes, and practices (KAP) in this area. METHODS: Between June and July 2023, we recruited hemodialysis nurses from 21 cities in Guangdong Province using a convenience sampling method. Four questionnaires-the General Data Questionnaire, the KAP Scale of Arteriovenous Access Assessment among Hemodialysis Nurses, the Utrecht Work Engagement Scale, and the NASA Task Load Index-were utilized for data collection through the Questionnaire Star platform. FINDINGS: Of the 530 hemodialysis nurses participating in the study, 458 (86.4%) had a valid response. The participants demonstrated moderate knowledge and practice levels regarding arteriovenous access assessment and exhibited positive attitudes. We identified several factors related to arteriovenous access assessment that predict KAP in hemodialysis nurses. These factors included years of experience as a hemodialysis nurse, whether a nurse's knowledge of physical examination was sufficient to meet clinical needs, whether a nurse had received training in performing physical examination, whether a nurse's department regularly checked the quality of physical examination, and nurses' levels of work engagement and mental workload. All factors explained 32.4% of the variance in participants' KAP regarding arteriovenous access assessment. DISCUSSION: Improving hemodialysis nurses' assessment of arteriovenous access is crucial to ensure optimal patient care. Dialysis center managers and educators should prioritize understanding hemodialysis nurses' KAP of arteriovenous access assessment and any factors influencing these areas.