[Rethinking the scope of lymphadenectomy after neoadjuvant immunotherapy for locally advanced gastric cancer].

Radical gastrectomy is the core of comprehensive treatment for patients with locally advanced gastric cancer,while reasonable and standardized lymphadenectomy is the key to radical gastrectomy.With the continuous development of treatment methods and therapeutic drugs for advanced gastric cancer, it is worth exploring whether the scope of lymphadenectomy needs to be changed. Neoadjuvant immunotherapy has brought a new breakthrough for locally advanced gastric cancer, increased pathological complete response rate, reduced clinical stage of tumors, and increased radical surgical resection rate, but it has not brought long-term benefits to patients. Lymph nodes play an important role in human anti-tumor immune response, and some basic studies suggest that preserving some normal lymph nodes may be more helpful to enhance the efficacy of immunotherapy. Thus, in the era of immunotherapy, the extent of lymph node dissection for locally advanced gastric cancer needs to balance continuous drug benefits, patient quality of life, and survival benefits, awaiting further high-quality clinical research for determination. Questions such as how to differentiate between normal and metastatic lymph nodes, how to rationally preserve normal lymph nodes, and whether preserving partial lymph node function can lead to greater benefits for patients from immunotherapy warrant further exploration.

[The Development of SpCas9 Variants with High Specificity and Efficiency Based on the HH Theory].

Streptococcus pyogenes Cas9 (SpCas9) is the most popular tool in gene editing; however, off-target mutagenesis is one of the biggest impediments in its application. In our previous study, we proposed the HH theory, which states that sgRNA/DNA hybrid (hybrid) extrusion-induced enhancement of hydrophobic interactions between the hybrid and REC3/HNH is a key factor in cleavage initiation. Based on the HH theory, we analyzed the interactions between the REC3 domain and hybrid and obtained 8 mutant sites. We designed 8 SpCas9 variants (V1-V8), used digital droplet PCR to assess SpCas9-induced DNA indels in human cells, and developed high-fidelity variants. Thus, the HH theory may be employed to further optimize SpCas9-mediated genome editing systems, and the resultant V3, V6, V7, and V8 SpCas9 variants may be valuable for applications requiring high-precision genome editing.

Changes in tau phosphorylation levels in the hippocampus and frontal cortex following chronic stress

Studies have indicated that early-life or early-onset depression is associated with a 2- to 4-fold increased risk of developing Alzheimers disease (AD). In AD, aggregation of an abnormally phosphorylated form of the tau protein may be a key pathological event. Tau is known to play a major role in promoting microtubule assembly and stabilization, and in maintaining the normal morphology of neurons. Several studies have reported that stress may induce tau phosphorylation. The main aim of the present study was to investigate possible alterations in the tau protein in the hippocampus and frontal cortex of 32 male Sprague-Dawley rats exposed to chronic unpredictable mild stress (CUMS) and then re-exposed to CUMS to mimic depression and the recurrence of depression, respectively, in humans. We evaluated the effects of CUMS, fluoxetine, and CUMS re-exposure on tau and phospho-tau. Our results showed that a single exposure to CUMS caused a significant reduction in sucrose preference, indicating a state of anhedonia. The change in behavior was accompanied by specific alterations in phospho-tau protein levels, but fluoxetine treatment reversed the CUMS-induced impairments. Moreover, changes in sucrose preference and phospho-tau were more pronounced in rats re-exposed to CUMS than in those subjected to a single exposure. Our results suggest that changes in tau phosphorylation may contribute to the link between depression and AD.