Disease-associated astrocyte epigenetic memory promotes CNS pathology

Disease-associated astrocyte subsets contribute to the pathology of neurologic diseases, including multiple sclerosis and experimental autoimmune encephalomyelitis1-8 (EAE), an experimental model for multiple sclerosis. However, little is known about the stability of these astrocyte subsets and their ability to integrate past stimulation events. Here we report the identification of an epigenetically controlled memory astrocyte subset that exhibits exacerbated pro-inflammatory responses upon rechallenge. Specifically, using a combination of single-cell RNA sequencing, assay for transposase-accessible chromatin with sequencing, chromatin immunoprecipitation with sequencing, focused interrogation of cells by nucleic acid detection and sequencing, and cell-specific in vivo CRISPR-Cas9-based genetic perturbation studies we established that astrocyte memory is controlled by the metabolic enzyme ATP-citrate lyase (ACLY), which produces acetyl coenzyme A (acetyl-CoA) that is used by histone acetyltransferase p300 to control chromatin accessibility. The number of ACLY+p300+ memory astrocytes is increased in acute and chronic EAE models, and their genetic inactivation ameliorated EAE. We also detected the pro-inflammatory memory phenotype in human astrocytes in vitro; single-cell RNA sequencing and immunohistochemistry studies detected increased numbers of ACLY+p300+ astrocytes in chronic multiple sclerosis lesions. In summary, these studies define an epigenetically controlled memory astrocyte subset that promotes CNS pathology in EAE and, potentially, multiple sclerosis. These findings may guide novel therapeutic approaches for multiple sclerosis and other neurologic diseases.

Disease-associated astrocyte epigenetic memory promotes CNS pathology

Astrocytes play important roles in the central nervous system (CNS) physiology and pathology. Indeed, astrocyte subsets defined by specific transcriptional activation states contribute to the pathology of neurologic diseases, including multiple sclerosis (MS) and its pre-clinical model experimental autoimmune encephalomyelitis (EAE) 1-8 . However, little is known about the stability of these disease-associated astrocyte subsets, their regulation, and whether they integrate past stimulation events to respond to subsequent challenges. Here, we describe the identification of an epigenetically controlled memory astrocyte subset which exhibits exacerbated pro-inflammatory responses upon re-challenge. Specifically, using a combination of single-cell RNA sequencing (scRNA-seq), assay for transposase-accessible chromatin with sequencing (ATAC-seq), chromatin immunoprecipitation with sequencing (ChIP-seq), focused interrogation of cells by nucleic acid detection and sequencing (FIND-seq), and cell-specific in vivo CRISPR/Cas9-based genetic perturbation studies we established that astrocyte memory is controlled by the metabolic enzyme ATP citrate lyase (ACLY), which produces acetyl coenzyme A (acetyl-CoA) used by the histone acetyltransferase p300 to control chromatin accessibility. ACLY + p300 + memory astrocytes are increased in acute and chronic EAE models; the genetic targeting of ACLY + p300 + astrocytes using CRISPR/Cas9 ameliorated EAE. We also detected responses consistent with a pro-inflammatory memory phenotype in human astrocytes in vitro ; scRNA-seq and immunohistochemistry studies detected increased ACLY + p300 + astrocytes in chronic MS lesions. In summary, these studies define an epigenetically controlled memory astrocyte subset that promotes CNS pathology in EAE and, potentially, MS. These findings may guide novel therapeutic approaches for MS and other neurologic diseases.

Neuroinflammation: An astrocyte perspective

Astrocytes are abundant glial cells in the central nervous system (CNS) that play active roles in health and disease. Recent technologies have uncovered the functional heterogeneity of astrocytes and their extensive interactions with other cell types in the CNS. In this Review, we highlight the intricate interactions between astrocytes, other CNS-resident cells, and CNS-infiltrating cells as well as their potential therapeutic value in the context of inflammation and neurodegeneration.

Droplet-based forward genetic screening of astrocyte-microglia cross-talk

Cell-cell interactions in the central nervous system play important roles in neurologic diseases. However, little is known about the specific molecular pathways involved, and methods for their systematic identification are limited. Here, we developed a forward genetic screening platform that combines CRISPR-Cas9 perturbations, cell coculture in picoliter droplets, and microfluidic-based fluorescence-activated droplet sorting to identify mechanisms of cell-cell communication. We used SPEAC-seq (systematic perturbation of encapsulated associated cells followed by sequencing), in combination with in vivo genetic perturbations, to identify microglia-produced amphiregulin as a suppressor of disease-promoting astrocyte responses in multiple sclerosis preclinical models and clinical samples. Thus, SPEAC-seq enables the high-throughput systematic identification of cell-cell communication mechanisms.

Effectiveness of immunological agents in non-small cell lung cancer

BACKGROUND AND AIM

Non-small cell lung cancer (NSCLC) continues to claim millions of lives worldwide. Although its poor prognosis is largely attributed to the lack of adequate and precise detection technologies, cancer cells' suppression of the immune system adds on to the difficulty of identifying abnormal NSCLC tumors in their early stages. Therefore, cancer immunotherapy, which activates the immune system and helps it fight tumors, has recently become the most sought-after technique, especially in the advanced stages of NSCLC, where surgery or chemotherapy may or may not bring about the desired survival benefits in patients.

METHODS

This review focuses on the various immunotherapeutic interventions and their efficacy in advanced NSCLC clinical trials. Monoclonal antibodies like anti-PD-1/PD-L1 agents and anti-CTLA-4 antibodies, cancer vaccines, oncolytic viruses and adoptive T cell therapy have been discussed in brief. Furthermore, the effects of gender, age, and race on the efficacy of immune checkpoint inhibitors and suggest plausible future approaches in the realm of immuno-oncology.

RESULTS

Immunotherapy is used alone or in combination either with other immunological agents or with chemotherapy. However, the efficacy of these strategies depends extensively on various demographic variables, as some patients respond perfectly well to immunotherapy, while others do not benefit at all or experience disease progression. By targeting a "hallmark" of cancer (immune evasion), immunotherapy has transformed NSCLC management, though several barriers prevent its complete effectiveness.

CONCLUSIONS

All these immunological strategies should be interpreted in the current setting of synergistic treatment, in which these agents can be combined with chemotherapy, radiotherapy, and, or surgery following patient and tumor characteristics to proportionate the best-individualized treatment and achieve superior results. To better pursue this goal, further investigations on cost-effectiveness and sex-gender, race, and age differences in immunotherapy are needed.

Associations between initiating antihypertensive regimens on stage I-III colorectal cancer outcomes: A Medicare SEER cohort analysis

Purpose

Colorectal cancer (CRC) diagnosis is associated with high mortality in the United States and thus warrants the study of novel treatment approaches. Vascular changes are well observed in cancers and evidence indicates that antihypertensive (AH) medications may interfere with both tumor vasculature and in recruiting immune cells to the tumor microenvironment based on preclinical models. Extant literature also shows that AH medications are correlated with improved survival in some forms of cancer. Thus, this study sought to explore the impact of AH therapies on CRC outcomes.

Patients and Methods

This study was a non‐interventional, retrospective analysis of patients aged 65 years and older with CRC diagnosed from January 1, 2007 to December 31st, 2012 in the Surveillance, Epidemiology, and End‐Results (SEER)‐Medicare database. The association between AH drug utilization on AJCC stage I–III CRC mortality rates in patients who underwent treatment for cancer was examined using Cox proportional hazards models.

Results

The study cohort consisted of 13,982 patients diagnosed with CRC. Adjusted Cox proportional hazards regression showed that among these patients, the use of AH drug was associated with decreased cancer‐specific mortality (HR: 0.79, 95% CI: 0.75–0.83). Specifically, ACE inhibitors (hazard ratio [HR]: 0.84, 95% CI: 0.80–0.87), beta‐blockers (HR: 0.87, 95% CI: 0.84–0.91), and thiazide diuretics (HR: 0.83, 95% CI: 0.80–0.87) were found to be associated with decreased mortality. An association was also found between adherence to AH therapy and decreased cancer‐specific mortality (HR: 0.94, 95% CI: 0.90–0.98).

Conclusion

Further research needs to be performed, but AH medications may present a promising, low‐cost pathway to supporting CRC treatment for stage I–III cancers.