EUS-guided fiducial marker insertion for radiotherapy in advanced esophageal carcinoma: submucosal insertion may lead to less migration when compared to intratumoral insertion.

BACKGROUND: The use of radiotherapy is frequently required in the treatment of locally advanced esophageal squamous cell carcinoma. However, the margins of the tumor are often difficult to ascertain on computed tomography. Thus, EUS-guided fiducial marker insertion can aid the localization of the margins of the tumor. However, the optimal technique of the procedure is still uncertain. METHODS: This was a retrospective study of all patients that received EUS-guided fiducial marker insertion between March 2015 and December 2018. All patients suffering from esophageal squamous cell carcinoma scheduled for radiotherapy underwent the procedure within one week of the scheduled appointment. Gold fiducial markers were inserted under EUS guidance either intratumorally or within the submucosa just proximal and distal to the tumor. Outcome parameters included tumor characteristics, early and late migration rates, and tumor response rates. RESULTS: During the study period, 40 patients were recruited. 10 fiducial markers were placed intratumorally and 30 markers were placed submucosally. When comparing fiducials that were placed in the submucosa versus intratumorally, significantly more fiducials had early (40% vs 0%, RR = 0.6, 95% CI 0.36, 1.00) and late migration (60% vs 0%, RR = 0.33, 95% CI 0.13, 0.84) in the intratumoral group. The submucosal group had significantly more patients intended for curative intent (96.7% vs 70%, RR = 0.34, 95%CI 0.003, 0.361) and more patients with partial and complete response. There was no difference between the gross tumor volume, the clinical target volume, and the total radiation dose. CONCLUSION: In esophageal carcinomas planned for radiotherapy, fiducial markers placed in the submucosa may lead to less migration.

Association Between Serum Folate Level and Toxicity of Capecitabine During Treatment for Colorectal Cancer.

BACKGROUND: Folate level was proposed to be a predictor for fluoropyrimidine-related toxicity. We conducted a prospective study to determine the association between serum and red-cell folate and capecitabine-related toxicity in patients with colorectal cancers. MATERIALS AND METHODS: Eligibility criteria included diagnosis of colorectal cancers; eligible patients who were scheduled to undergo capecitabine monotherapy or capecitabine-oxaliplatin (CAPOX) for adjuvant or palliative purposes. Exclusion criteria included concomitant radiotherapy or chemotherapy other than capecitabine or CAPOX and creatinine clearance <30 mL/min. Fasting serum and red-cell folate were measured prior to chemotherapy. Capecitabine was administered at 2,500 mg/m2 per day (monotherapy) or 2,000 mg/m2 per day (CAPOX) for 14 days every 3 weeks. The toxicity of the first four cycles was documented by clinical investigators who were blinded to folate levels. RESULTS: A total of 144 patients were recruited, of whom 126 were eligible; 40 patients had capecitabine alone, and 86 patients received CAPOX. The rates of grade 2 and grade 3 toxicity were 63.5% and 14.3%, respectively. Nausea and vomiting were the most common grade ≥2 adverse event (47.7%), followed by hand-foot syndrome (25.4%), diarrhea (23.1%), and neutropenia (22.3%). Combination with oxaliplatin (odds ratio [OR], 2.77; p = .043) and serum folate (OR, 10.33; p = .002) were independent predictors of grade ≥2 toxicity. Red-cell folate was not predictive of toxicity. For every 10 nmol/L increment in serum folate, the risk of grade ≥2 toxicity increased by 9%. CONCLUSION: Serum folate level, but not red-cell folate, was associated with higher rate of grade ≥2 toxicity during capecitabine-based treatment. Excessive folate intake may be avoided before and during capecitabine-based chemotherapy. IMPLICATIONS FOR PRACTICE: This is the first prospective study to evaluate the association between serum folate level and capecitabine-related toxicity in patients with colon cancers. It shows that higher serum folate level is associated with increased risks of moderate to severe toxicity during capecitabine-based treatment. Excessive folate intake should be avoided before and during capecitabine-based chemotherapy.

Abiraterone acetate in metastatic castration-resistant prostate cancer - the unanticipated real-world clinical experience.

BACKGROUND: There is much interest in confirming whether the efficacy of abiraterone acetate (AA) demonstrated within the trial setting is reproducible in routine clinical practice. We report the clinical outcome of metastatic castration-resistant prostate cancer (mCRPC) patients treated with AA in real-life clinical practice. METHODS: The clinical records of mCRPC patients treated with AA from all 6 public oncology centers in Hong Kong between August 2011 and December 2014 were reviewed. The treatment efficacy and its determinants, and toxicities were determined. RESULTS: A total of 110 patients with mCRPC were treated with AA in the review period, of whom 58 were chemo-naive and 52 had received prior chemotherapy (post-chemo). The median follow-up time was 7.5/11.4 months for chemo-naive/post-chemo patients. 6.9/15.4 % of chemo-naive/post-chemo patients had visceral metastases. The median overall survival (OS) and progression-free survival (PFS) were 18.1/15.5 months and 6.7/6.4 months for chemo-naive/post-chemo patients, respectively. Among chemo-naive patients, those with visceral diseases had significantly inferior OS (2.8 vs 18.0 p = 0.0007) and PFS (2.8 vs 6.8 months, p = 0.0088) than those without. Pain control was comparable in both groups of patients. The most common grade 3 or above toxicities were hypertension (6.9/5.8 %) and hypokalemia (3.4/3.8 %) in chemo-naive/post-chemo patients. In multivariate analysis, the presence of prostate-specific antigen (PSA) response (≥50 % drop of PSA from baseline) within the first 3 months of therapy was associated with favorable OS and PFS in both chemo-naive and post-chemo group. CONCLUSIONS: In clinical practice outside the trial setting, OS after AA in our chemo-naive patient cohort (18.1 months) was considerably shorter than that reported in the COU-AA-302 trial (34.7 months), and the OS was particularly short in those with visceral metastases (2.8 months). Conversely, AA was efficacious in post-chemo patients. AA resulted in comparable pain control in both groups of patients. The presence of PSA response within the first 3 months of treatment was a significant determinant of survival.

Patient Preference of Apalutamide Versus Enzalutamide for Recurrent or Metastatic Hormone-sensitive Prostate Cancer: An Open-label, Randomized, Crossover Trial.

BACKGROUND AND OBJECTIVE: Treatment preference regarding apalutamide versus enzalutamide in prostate cancer (PCa) and the factors influencing decisions are largely unknown. Our aim was to investigate the preference for apalutamide versus enzalutamide among prostate cancer patients and their physicians and caregivers, and factors influencing their decision. METHODS: This was a prospective, open-label, randomized, crossover trial. Patients with recurrence of localized PCa or with metastatic disease not considered as high-risk or high-volume and on continued androgen deprivation therapy were recruited. All subjects received a trial of two agents, apalutamide (A) and enzalutamide (E), for 12 wk each, with a 5-wk washout period in between. The sequencing of the drugs was randomized. The primary outcome was patient preference for one the drugs, assessed at the end of the study. Other outcomes included factors influencing patient preference, a comparison of side-effect profiles, and patients' quality of life (QoL). Physician and caregiver preferences for the drugs and factors affecting their choice were also assessed. KEY FINDINGS AND LIMITATIONS: A total of 74 patients met the eligibility criteria and were randomized to the A â†’ E or E â†’ A arm. Of these, 66 patients (89.1%; 32 A â†’ E, 34 E â†’ A) completed the study. Baseline characteristics were comparable between the two groups, and ∼90% of the patients had low-volume metastatic disease. After completion of both treatments for 12 wk each, the difference in preference for A over E was 17.8%, with similar trends for preference of A over E among physicians (18.2%) and caregivers (22.4%). Fewer side effect was the most critical factor influencing the preference of patients. Among the side effects, less fatigue was the benefit of A over E most frequently reported. No notable difference in QoL was observed between the two drugs. However, the study was terminated on interim analysis and the results might not be conclusive. CONCLUSIONS: There was a trend for preference of A over E among patients with predominantly low-volume recurrent or metastatic PCa and their physicians and caregivers. Fewer side effects was the most critical factor influencing their choice. PATIENT SUMMARY: Patients with low-volume recurrent or metastatic prostate cancer tended to prefer treatment with apalutamide over enzalutamide. Side effects were the most critical factor influencing treatment preference.

High-content synaptic phenotyping in human cellular models reveals a role for BET proteins in synapse assembly.

Resolving fundamental molecular and functional processes underlying human synaptic development is crucial for understanding normal brain function as well as dysfunction in disease. Based upon increasing evidence of species-divergent features of brain cell types, coupled with emerging studies of complex human disease genetics, we developed the first automated and quantitative high-content synaptic phenotyping platform using human neurons and astrocytes. To establish the robustness of our platform, we screened the effects of 376 small molecules on presynaptic density, neurite outgrowth, and cell viability, validating six small molecules that specifically enhanced human presynaptic density in vitro. Astrocytes were essential for mediating the effects of all six small molecules, underscoring the relevance of non-cell-autonomous factors in synapse assembly and their importance in synaptic screening applications. Bromodomain and extraterminal (BET) inhibitors emerged as the most prominent hit class and global transcriptional analyses using multiple BET inhibitors confirmed upregulation of synaptic gene expression. Through these analyses, we demonstrate the robustness of our automated screening platform for identifying potent synaptic modulators, which can be further leveraged for scaled analyses of human synaptic mechanisms and drug discovery efforts.

Molecular convergence between Down syndrome and fragile X syndrome identified using human pluripotent stem cell models.

Down syndrome (DS), driven by an extra copy of chromosome 21 (HSA21), and fragile X syndrome (FXS), driven by loss of the RNA-binding protein FMRP, are two common genetic causes of intellectual disability and autism. Based upon the number of DS-implicated transcripts bound by FMRP, we hypothesize that DS and FXS may share underlying mechanisms. Comparing DS and FXS human pluripotent stem cell (hPSC) and glutamatergic neuron models, we identify increased protein expression of select targets and overlapping transcriptional perturbations. Moreover, acute upregulation of endogenous FMRP in DS patient cells using CRISPRa is sufficient to significantly reduce expression levels of candidate proteins and reverse 40% of global transcriptional perturbations. These results pinpoint specific molecular perturbations shared between DS and FXS that can be leveraged as a strategy for target prioritization; they also provide evidence for the functional relevance of previous associations between FMRP targets and disease-implicated genes.

Ethnic Pharmacogenomic Differences in the Management of Asian Patients with Metastatic Prostate Cancer.

Progression to metastatic disease occurs in about half of all men who develop prostate cancer (PC), one of the most common cancers in men worldwide. Androgen deprivation therapy has been the mainstay therapy for patients with metastatic PC (mPC) since the 1940s. In the last decade, there has been unprecedented advancement in systemic therapies, e.g., taxane, androgen-signalling pathway inhibitors, and biomarker-driven targeted therapies for various stages of disease, resulting in overall survival improvement. Adding to ongoing controversies over how best to treat these patients is the recognition that ethnicity may influence prognosis and outcomes. This review discusses recent evidence for the impacts of Asian ethnicity specifically, which includes environmental, sociocultural, and genetic factors, on the approach to pharmacological management of mPC. Clear inter-ethnic differences in drug tolerability, serious adverse events (AEs), and genetic heterogeneity must all be considered when dosing and scheduling for treatment, as well as designing future precision studies in PC.

Prospective Randomized Phase II Study of Stereotactic Body Radiotherapy (SBRT) vs. Conventional Fractionated Radiotherapy (CFRT) for Chinese Patients with Early-Stage Localized Prostate Cancer.

BACKGROUND: Stereotactic body radiotherapy (SBRT) has potential radiobiologic and economic advantages over conventional fractionated radiotherapy (CFRT) in localized prostate cancer (PC). This study aimed to compare the effects of these two distinct fractionations on patient-reported quality of life (PRQOL) and tolerability. METHODS: In this prospective phase II study, patients with low- and intermediate-risk localized PC were randomly assigned in a 1:1 ratio to the SBRT (36.25 Gy/5 fractions/2 weeks) or CFRT (76 Gy/38 fractions/7.5 weeks) treatment groups. The primary endpoint of variation in PRQOL at 1 year was assessed by changes in the Expanded Prostate Cancer Index Composite (EPIC) questionnaire scores and analysed by z-tests and t-tests. RESULTS: Sixty-four eligible Chinese men were treated (SBRT, n = 31; CFRT, n = 33) with a median follow-up of 2.3 years. At 1 year, 40.0%/46.9% of SBRT/CFRT patients had a >5-point decrease in bowel score (p = 0.08/0.28), respectively, and 53.3%/46.9% had a >2-point decrease in urinary score (p = 0.21/0.07). There were no significant differences in EPIC score changes between the arms at 3, 6, 9 and 12 months, but SBRT was associated with significantly fewer grade ≥ 1 acute and 1-year late gastrointestinal toxicities (acute: 35% vs. 87%, p < 0.0001; 1-year late: 64% vs. 84%, p = 0.03), and grade ≥ 2 acute genitourinary toxicities (3% vs. 24%, p = 0.04) compared with CFRT. CONCLUSION: SBRT offered similar PRQOL and less toxicity compared with CFRT in Chinese men with localized PC.

Rationally Designed Base Editors for Precise Editing of the Sickle Cell Disease Mutation.

Base editors are fusions of a deaminase and CRISPR-Cas ribonucleoprotein that allow programmable installment of transition mutations without double-strand DNA break intermediates. The breadth of potential base editing targets is frequently limited by the requirement of a suitably positioned Cas9 protospacer adjacent motif. To address this, we used structures of Cas9 and TadA to design a set of inlaid base editors (IBEs), in which deaminase domains are internal to Cas9. Several of these IBEs exhibit shifted editing windows and greater editing efficiency, enabling editing of targets outside the canonical editing window with reduced DNA and RNA off-target editing frequency. Finally, we show that IBEs enable conversion of the pathogenic sickle cell hemoglobin allele to the naturally occurring HbG-Makassar variant in patient-derived hematopoietic stem cells.

Dynamic Changes of Post-Radiotherapy Plasma Epstein-Barr Virus DNA in a Randomized Trial of Adjuvant Chemotherapy Versus Observation in Nasopharyngeal Cancer.

PURPOSE: To study the dynamic changes in plasma Epstein-Barr virus (pEBV) DNA after radiotherapy in nasopharyngeal cancer (NPC). EXPERIMENTAL DESIGN: We conducted a randomized controlled trial of adjuvant chemotherapy versus observation in patients with NPC who had detectable pEBV DNA at 6 weeks post-radiotherapy. Randomized patients had a second pEBV DNA checked at 6 months post-randomization. The primary endpoint was progression-free survival (PFS). RESULTS: We prospectively enrolled 789 patients. Baseline post-radiotherapy pEBV DNA was undetectable in 573 (72.6%) patients, and detectable in 216 (27.4%) patients, of whom 104 (13.2%) patients were eligible for randomization to adjuvant chemotherapy (n = 52) versus observation (n = 52). The first post-radiotherapy pEBV DNA had a sensitivity of 0.48, specificity of 0.81, area under receiver-operator characteristics curve (AUC) of 0.65, false positive (FP) rate of 13.8%, and false negative (FN) rate of 14.4% for disease progression. The second post-radiotherapy pEBV DNA had improved sensitivity of 0.81, specificity of 0.75, AUC of 0.78, FP rate of 14.3%, and FN rate of 8.1%. Patients with complete clearance of post-radiotherapy pEBV DNA (51%) had survival superior to that of patients without post-radiotherapy pEBV DNA clearance (5-year PFS, 85.5% vs. 23.3%; HR, 9.6; P < 0.0001), comparable with patients with initially undetectable post-radiotherapy pEBV DNA (5-year PFS, 77.1%), irrespective of adjuvant chemotherapy or observation. CONCLUSIONS: Patients with NPC with detectable post-radiotherapy pEBV DNA who experienced subsequent pEBV DNA clearance had superior survival comparable with patients with initially undetectable post-radiotherapy pEBV DNA. Post-radiotherapy pEBV DNA clearance may serve as an early surrogate endpoint for long-term survival in NPC.

A multiplexed gRNA piggyBac transposon system facilitates efficient induction of CRISPRi and CRISPRa in human pluripotent stem cells.

CRISPR-Cas9-mediated gene interference (CRISPRi) and activation (CRISPRa) approaches hold promise for functional gene studies and genome-wide screens in human pluripotent stem cells (hPSCs). However, in contrast to CRISPR-Cas9 nuclease approaches, the efficiency of CRISPRi/a depends on continued expression of the dead Cas9 (dCas9) effector and guide RNA (gRNA), which can vary substantially depending on transgene design and delivery. Here, we design and generate new fluorescently labeled piggyBac (PB) vectors to deliver uniform and sustained expression of multiplexed gRNAs. In addition, we generate hPSC lines harboring AAVS1-integrated, inducible and fluorescent dCas9-KRAB and dCas9-VPR transgenes to allow for accurate quantification and tracking of cells that express both the dCas9 effectors and gRNAs. We then employ these systems to target the TCF4 gene in hPSCs and assess expression levels of the dCas9 effectors, individual gRNAs and targeted gene. We also assess the performance of our PB system for single gRNA delivery, confirming its utility for library format applications. Collectively, our results provide proof-of-principle application of a stable, multiplexed PB gRNA delivery system that can be widely exploited to further enable genome engineering studies in hPSCs. Paired with diverse CRISPR tools including our dual fluorescence CRISPRi/a cell lines, this system can facilitate functional dissection of individual genes and pathways as well as larger-scale screens for studies of development and disease.

A randomized study of olanzapine-containing versus standard antiemetic regimens for the prevention of chemotherapy-induced nausea and vomiting in Chinese breast cancer patients.

OBJECTIVES: Chemotherapy-induced nausea and vomiting (CINV) are distressing symptoms. This randomized study evaluated the antiemetic efficacies of standard antiemetic regimen with/without olanzapine. PATIENTS AND METHODS: Eligible patients were chemotherapy-naive Chinese breast cancer patients who were planned for (neo)adjuvant doxorubicin/cyclophosphamide. Antiemetic regimen for all studied population included aprepitant, ondansetron and dexamethasone; patients were randomized to Olanzapine (with olanzapine) or Standard arms (without olanzapine). Patients filled in self-reported diaries and completed visual analogue scales for nausea, as well as Functional Living Index-Emesis questionnaires. Blood profiles including fasting glucose and lipids were monitored. RESULTS: 120 patients were randomized. In Cycle 1 doxorubicin/cyclophosphamide, the Olanzapine arm had significantly higher rates of "Complete Response" than the Standard arm: 65.0% vs 38.3% in the overall period (p = 0.0035), 70.0% vs 51.7% in the acute period (p = 0.0397) and 92.9% vs 74.2% in the delayed period (p = 0.0254). Olanzapine arm also had significantly higher rates of "No significant nausea" and "No nausea" during all 3 time-frames and better QOL. Similar findings were also revealed throughout multiple cycles. Pre-study abnormalities in glucose and lipids occurred in 39.7% and 34.2% of the studied population respectively; there were no differences in these parameters between the two arms at end-of-study assessment. CONCLUSION: The addition of olanzapine to standard aprepitant-based antiemetic regimen provides clinically meaningful improvement in controlling CINV. This was associated with a positive impact on QOL and tolerable toxicity profiles among Chinese breast cancer patients receiving doxorubicin/cyclophosphamide chemotherapy. Further studies on metabolic profiles of breast cancer patients are warranted.

A Territory-wide, Multicenter, Age- and Prostate-specific Antigen-matched Study Comparing Chemohormonal Therapy and Hormonal Therapy Alone in Chinese Men With Metastatic Hormone-sensitive Prostate Cancer.

BACKGROUND: There is a lack of real-world data regarding the treatment outcomes of chemohormonal therapy versus hormonal therapy alone in Chinese men with metastatic hormone-sensitive prostate cancer. PATIENTS AND METHODS: We conducted a territory-wide, multicenter, age- and prostate-specific antigen (PSA)-matched cohort study comparing chemohormonal therapy and hormonal therapy alone in Chinese men with metastatic hormone-sensitive prostate cancer. Patient and disease characteristics were reviewed. The primary outcome was PSA progression-free survival. Secondary outcomes included clinical progression-free survival and castration resistance-free survival. Kaplan-Meier and multivariate Cox regression analyses were performed. RESULTS: From January 2015 to July 2016, 32 Chinese men with metastatic hormone-sensitive prostate cancer were treated with chemohormonal therapy, and they were matched to 32 Chinese men who were treated with hormonal therapy alone. Patient and disease characteristics were similar between the 2 groups. The chemohormonal therapy group had a significantly better PSA progression-free survival (P = .001) and castration resistance-free survival (P = .002) than the hormonal therapy group. There was no significant difference in the clinical progression-free survival between the 2 groups. Upon multivariate Cox regression analyses, the use of chemohormonal therapy was significantly associated with a longer time to PSA progression (hazard ratio, 0.31; 95% confidence interval, 0.31-0.73; P = .008) and a longer time to castration resistance (hazard ratio, 0.38; 95% confidence interval, 0.17-0.83; P = .015), but was not associated with clinical progression. CONCLUSIONS: The use of chemohormonal therapy could prevent PSA progression and the development of castration resistance when compared with hormonal therapy alone in Chinese men with metastatic hormone-sensitive prostatic cancer.

Preliminary efficacy and tolerability of chemohormonal therapy in metastatic hormone-naïve prostate cancer: The first real-life experience in Asia.

INTRODUCTION: A substantial survival benefit with chemohormonal therapy has been proven by the CHAARTED and STAMPEDE studies, and this clinical approach has emerged as the standard of care for patients with metastatic hormone-naïve prostate cancer (mHSPC). However, because its clinical efficacy and tolerability in Asian patients remains uncertain, this study aims to evaluate preliminary results of its use in Hong Kong. METHODS: The clinical records of mHSPC patients treated with chemohormonal therapy from all six public oncology centers in Hong Kong between January 2015 and July 2016 were reviewed. Time to castration-resistant prostate cancer (CRPC), treatment-related complications, prostate-specific antigen (PSA) response and the time to PSA nadir were assessed. RESULTS: A total of 32 patients (median age, 66 years) were treated with chemohormonal therapy in the review period. After median follow-up time of 11.4 months, the median time to CRPC and time to PSA nadir were 19.5 months and 7 months, respectively. PSA response (>50% drop in PSA level from baseline) was achieved in all patients and the median maximal PSA response was 99.6%. The rates of grade 3 or 4 febrile neutropenia, neutropenia and anemia were 12.5%, 40.6% and 3.1%, respectively. CONCLUSION: Early efficacy with chemohormonal therapy in Asian mHSPC patients was comparable to the pivotal study and biochemical response is promising. The high frequency of hematologic toxicities in Asian patients highlights the importance of proper patient selection and pre-emptive use of granulocyte colony-stimulating factor.

Differences in clinical outcome between docetaxel and abiraterone acetate as the first-line treatment in chemo-naïve metastatic castration-resistant prostate cancer patients with or without the ineligible clinical factors of the COU-AA-302 study.

BACKGROUND: This study aimed to compare the efficacy of abiraterone acetate (AA) versus docetaxel (T) as first-line treatment in chemo-naïve metastatic castration-resistant prostate cancer (mCRPC) patients with or without the ineligible factors of the COU-AA-302 study (presence of visceral metastases, symptomatic disease, and/or Eastern Cooperative Oncology Group performance status ≥ 2). MATERIALS AND METHODS: The clinical records of chemo-naïve mCRPC patients who received AA in six public oncology centers or T in two of these centers between 2003 and 2014 were reviewed. The survival time was compared among four subgroups of patients: those with ineligible factors administered AA (Group Ineligible-AA) or T (Group Ineligible-T), and those without ineligible factors and administered AA (Group Eligible-AA) or T (Group Eligible-T). RESULTS: During the study period, we identified 115 mCRPC patients who received AA or T, among whom 29, 36, 29, and 21 patients were classified as Groups Ineligible-AA, Ineligible-T, Eligible-AA, and Eligible-T, respectively. Both Group Ineligible-AA and Group Eligible-AA had significantly longer progression-free survival (PFS) and similar overall survival (OS) as Group Ineligible-T and Group Eligible-T (Ineligible, PFS: 6.3 vs. 5.9 months, P = 0.0234, OS: 7.8 vs. 15.7 months, P = 0.1601; Eligible, PFS: 9.8 vs. 5.6 months, P = 0.0437, OS: 20.5 vs. 18.2 months, P = 0.7820). CONCLUSIONS: Compared to T, AA treatment resulted in longer PFS and similar OS in chemo-naïve mCRPC patients, irrespective of the presence of ineligible factors, suggesting that the initial treatment by AA may still be beneficial to those with the aforementioned ineligible factors.

A Scaled Framework for CRISPR Editing of Human Pluripotent Stem Cells to Study Psychiatric Disease.

Scaling of CRISPR-Cas9 technology in human pluripotent stem cells (hPSCs) represents an important step for modeling complex disease and developing drug screens in human cells. However, variables affecting the scaling efficiency of gene editing in hPSCs remain poorly understood. Here, we report a standardized CRISPR-Cas9 approach, with robust benchmarking at each step, to successfully target and genotype a set of psychiatric disease-implicated genes in hPSCs and provide a resource of edited hPSC lines for six of these genes. We found that transcriptional state and nucleosome positioning around targeted loci was not correlated with editing efficiency. However, editing frequencies varied between different hPSC lines and correlated with genomic stability, underscoring the need for careful cell line selection and unbiased assessments of genomic integrity. Together, our step-by-step quantification and in-depth analyses provide an experimental roadmap for scaling Cas9-mediated editing in hPSCs to study psychiatric disease, with broader applicability for other polygenic diseases.

Nerve fiber layer thinning lags retinal ganglion cell density following crush axonopathy.

PURPOSE: We investigated the progressive nature of neurodegenerative structural changes following injury to retinal ganglion cell (RGC) axons using quantifiable and noninvasive in vivo imaging techniques. METHODS: To track degenerative RGC progression in retinas following optic nerve crush (ONC) injury, spectral-domain optical coherence tomography (SD-OCT) was used to quantitate the RGC nerve fiber layer (NFL) density. The RGC soma cell density (RCD) was measured by confocal scanning laser ophthalmoscopy (CSLO). The RCD counts were performed using blood vessels as landmarks to anatomically track defined progressive changes in enhanced yellow fluorescent fusion protein (EYFP)-labeled RGCs. RESULTS: Following ONC injury, 68% of the observed decrease in RCD measured by CSLO and 54% of the NFL thickness obtained by SD-OCT imaging (N=4 retinas) occurred within the first week. Between days 7 and 14, an additional 22% decrease in RCD was concurrent with a 31% decrease in overall NFL thickness. Finally, between days 14 and 21, an additional 10% decrease in RCD measured in vivo by CSLO and 15% decrease in NFL thickness by SD-OCT was observed. CONCLUSIONS: Our data suggest that in vivo CSLO imaging of EYFP-RGC expression and SD-OCT measured NFL thickness are fast and reliable methods that longitudinally track neurodegenerative progression following ONC injury. Neurodegenerative changes in NFL thickness measured by SD-OCT imaging have the same overall trajectory as those observed by CSLO for RCD; however, changes in NFL thickness initially lag behind in vivo RGC soma counts with a slower decline in overall measurable change.

Effects of glaucoma on Chrna6 expression in the retina.

PURPOSE: Recent advances in technology now provide tools capable of tracking genome-wide expression changes occurring in progressive pathological processes. The present experiments were carried out to determine if acetylcholine receptor α 6 subunit (Chrna6) is a reliable retinal ganglion cell (RGC) marker in adult mouse eyes and if Chrna6 expression can be used to track progressive loss of RGCs, such as is observed in the DBA/2J glaucoma model. METHODS: Data sets derived from the BXD strains were used to extract gene expression signatures for RGCs. Pooled retinas from DBA/2J or C57BL/6J cases at 1-3 months, 12 months, and 16-17 months were prepared for gene-array and RT-PCR analysis. Globes were fixed in paraformaldehyde and sectioned for immunofluorescence with antibodies against Chrna6. RESULTS: Chrna6 has a cellular expression signature for RGCs with high correlation to Thy1 (r = 0.65), a recognized RGC marker. Immunofluorescence experiments confirm that in the young and adult mouse retina, Chrna6 is preferentially expressed by RGCs. We further show that C3H/HeJ retinas, which lack photoreceptors, also express Chrna6 in the RGC layer. Gene expression array analyses, confirmed by RT-PCR, show progressive loss of Chrna6 expression in retinas of the DBA/2J glaucomatous mouse retinas. CONCLUSIONS: Quantitative trait locus analysis provides support for Chrna6 as a RGC marker. Chrna6 expression decreases with death of RGCs in glaucomatous DBA/2J mice and after optic nerve crush injury, further supporting Chrna6 as a reliable RGC marker. High expression of RGC Chrna6 in the absence of photoreceptors is suggestive that Chrna6 expression by RGCs is independent of photoreceptor-derived stimuli.