Stented endoscopic third ventriculostomy: technique, safety, and indications-a multicenter multinational study.

PURPOSE: Endoscopic third ventriculostomy (ETV) is an effective treatment for obstructive hydrocephalus. Secondary stoma closure may be life threatening and is the most common reason for late ETV failure, mostly secondary to local scarring. Local stents intended to maintain patency are rarely used. In this study, we summarize our experience using stented ETV (sETV), efficacy, and safety. MATERIAL AND METHODS: Data was retrospectively collected from all consecutive patients who underwent ETV with stenting at four centers. Collected data included indications for using sETV, hydrocephalic history, surgical technique, outcomes, and complications. RESULTS: Sixty-seven cases were included. Forty had a primary sETV, and 27 had a secondary sETV (following a prior shunt, ETV, or both). The average age during surgery was 22 years. Main indications for sETV included an adjacent tumor (n = 15), thick or redundant tuber cinereum (n = 24), and prior ETV failure (n = 16). Fifty-nine patients (88%) had a successful sETV. Eight patients failed 11 ± 8 months following surgery. Reasons for failure included obstruction of the stent, reabsorption insufficiency, and CSF leak (n = 2 each), and massive hygroma and tumor spread (n = 1 each). Complications included subdural hygroma (n = 4), CSF leak (n = 2), and stent malposition (n = 1). There were no complications associated with two stent removals. CONCLUSION: Stented ETV appears to be feasible and safe. It may be indicated in selected cases such as patients with prior ETV failure, or as a primary treatment in cases with anatomical alterations caused by tumors or thickened tuber cinereum. Future investigations are needed to further elucidate its role in non-communicating hydrocephalus.

Avidity optimization of a MAGE-A1-specific TCR with somatic hypermutation.

A T-cell receptor (TCR) with optimal avidity to a tumor antigen can be used to redirect T cells to eradicate cancer cells via adoptive cell transfer. Cancer testis antigens (CTAs) are attractive targets because they are expressed in the testis, which is immune-privileged, and in the tumor. However, CTAs are self-antigens and natural TCRs to CTAs have low affinity/avidity due to central tolerance. We previously described a method of directed evolution of TCR avidity using somatic hypermutation. In this study, we made several improvements to this method and enhanced the avidity of the hT27 TCR, which is specific for the cancer testis antigen HLA-A2-MAGE-A1278-286 . We identified eight point mutations with varying degrees of improved avidity. Human T cells transduced with TCRs containing these mutations displayed enhanced tetramer binding, IFN-γ and IL2 production, and cytotoxicity. Most of the mutations have retained specificity, except for one mutant with extremely high avidity. We demonstrate that somatic hypermutation is capable of optimizing avidity of clinically relevant TCRs for immunotherapy.

Single genomic enhancers drive experience-dependent GABAergic plasticity to maintain sensory processing in the adult cortex.

Experience-dependent plasticity of synapses modulates information processing in neural circuits and is essential for cognitive functions. The genome, via non-coding enhancers, was proposed to control information processing and circuit plasticity by regulating experience-induced transcription of genes that modulate specific sets of synapses. To test this idea, we analyze here the cellular and circuit functions of the genomic mechanisms that control the experience-induced transcription of Igf1 (insulin-like growth factor 1) in vasoactive intestinal peptide (VIP) interneurons (INs) in the visual cortex of adult mice. We find that two sensory-induced enhancers selectively and cooperatively drive the activity-induced transcription of Igf1 to thereby promote GABAergic inputs onto VIP INs and to homeostatically control the ratio between excitation and inhibition (E/I ratio)-in turn, this restricts neural activity in VIP INs and principal excitatory neurons and maintains spatial frequency tuning. Thus, enhancer-mediated activity-induced transcription maintains sensory processing in the adult cortex via homeostatic modulation of E/I ratio.

Meso-seq for in-depth transcriptomics in ultra-low amounts of FACS-purified neuronal nuclei.

Profiling of gene expression in sparse populations of genetically defined neurons is essential for dissecting the molecular mechanisms that control the development and plasticity of neural circuits. However, current transcriptomic approaches are ill suited for detailed mechanistic studies in sparse neuronal populations, as they either are technically complex and relatively expensive (e.g., single-cell RNA sequencing [RNA-seq]) or require large amounts of input material (e.g., traditional bulk RNA-seq). Thus, we established Meso-seq, a meso-scale protocol for identifying more than 10,000 robustly expressed genes in as little as 50 FACS-sorted neuronal nuclei. We demonstrate that Meso-seq works well for multiple neuroscience applications, including transcriptomics in antibody-labeled cortical neurons in mice and non-human primates, analyses of experience-regulated gene programs, and RNA-seq from visual cortex neurons labeled ultra-sparsely with viruses. Given its simplicity, robustness, and relatively low costs, Meso-seq is well suited for molecular-mechanistic studies in ultra-sparse neuronal populations in the brain.