Abhirami Ramakrishnan

Abhirami Ramakrishnan

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Abhirami Ramakrishnan

Abrams Research Center on Neurogenomics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 May 2026 in Nature Neuroscience
Verified
Journal Article
Open access
ZZZiyang Zhang
Ziyang Zhang
LOLynn van Olst
Lynn van Olst
FAFrancesco Alessandrini
Francesco Alessandrini
MWMatthew Wright
Matthew Wright
AEAlex J. Edwards
Alex J. Edwards
DGDavid Gate
David Gate
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder marked by progressive motor neuron (MN) degeneration in the brain and spinal cord. Although neuroinflammation is increasingly recognized as a hallmark of ALS, the precise molecular programs linking immune responses to MN pathology remain poorly defined. Using an integrated approach that combines single-cell and bulk RNA sequencing with spatial proteogenomics, we characterized both shared and distinct immune dynamics in peripheral blood and spinal cord tissues from patients with sporadic ALS and those carrying C9orf72 repeat expansions. Our analysis revealed broad immune remodeling in C9orf72 ALS, ALS subtype-specific and progression-associated differences in monocyte activation and antigen-experienced CD8 effector memory T cells with clonal features consistent with antigen-driven responses. Spatial mapping revealed complement activation and lipid-programmed myeloid states converging at sites of MN loss and TDP-43 pathology. Together, these findings connect peripheral and central immune alterations to ALS heterogeneity and highlight stratified immunomodulation as a potential therapeutic strategy.

19 March 2026 in Nature Communications
Verified
Journal Article
Open access
PDF file
YYYongyong Yang
Yongyong Yang
TWTingyou Wang
Tingyou Wang
JFJoshua Fry
Joshua Fry
YLYingming Li
Yingming Li
QMQingshu Meng
Qingshu Meng
Rendong YangRendong Yang
Rendong Yang
LncRNAs have emerged as pivotal regulators in the development and progression of various human cancers. However, understanding the precise mechanisms by which lncRNAs influence cancer progression remains a substantial challenge, largely due to their cell type- and tissue-specific expression patterns and the lack of well-defined functional domains or motifs. In this study, we investigate the complex interplay between super-enhancers and lncRNAs through a comprehensive analysis of lncRNA expression in a cohort of metastatic castration-resistant prostate cancer patients. Our analysis identifies 1344 lncRNAs, among which an antisense lncRNA in the IGF1R locus named IGF1R-AS1 displayed the strongest super-enhancer association. Through pan-cancer transcriptome analysis, we find that IGF1R-AS1 is specifically transcribed in tumor specimens and is overexpressed in prostate and lung cancers. Notably, we reveal a non-canonical trans -acting role for IGF1R-AS1 whereby it interacts with chromatin remodeling complexes and architectural proteins to facilitate long-range chromatin looping between distal MYC enhancers and its promoter, leading to MYC overexpression and enhanced tumorigenicity. Collectively, our findings elucidate a mechanism by which a tumor-specific trans -acting lncRNA modulates oncogenic MYC expression through long-range chromatin interactions, suggesting IGF1R-AS1 may play an important role in the pathogenesis of MYC-driven malignancies.

25 December 2023 in Alzheimer's & Dementia
Verified
Journal Article
Open access
LOLynn van Olst
Lynn van Olst
BSBrooke Simonton
Brooke Simonton
ARAbhirami Ramakrishnan
Abhirami Ramakrishnan
NPNatalie Piehl
Natalie Piehl
VTVictoria Teregulova
Victoria Teregulova
DGDavid Gate
David Gate
Background: Modern Alzheimer’s disease (AD) therapeutics include immunization against amyloid‐β (Aβ). Intriguingly, neuropathological examination of the first active Aβ vaccination trial (Elan Pharmaceuticals’ AN1792) showed some patients with evidence of Aβ clearance 15 years post‐vaccination. Yet, these patients progressed to severe dementia before death, possibly due to ongoing tau propagation. The AN1792 trial was halted when some participants developed aseptic meningoencephalitis driven by auto‐aggressive T cells. Imaging features of meningoencephalitis experienced by AN1792 subjects are pathologically reminiscent of amyloid‐related imaging abnormalities (ARIA) that currently hamper clinical trials and the therapeutic use of passive Aβ immunotherapy for AD.Method: Here, we utilized spatial transcriptomics to sequence RNA from formalin‐fixed paraffin‐embedded (FFPE) cortical brain sections from a unique neuropathological cohort of 14 immunized AD cases and a placebo‐control from AN1792. Additional controls included 6 naïve (unimmunized) AD cases and 3 non‐neurological disease controls.Result: We reveal a cytotoxic and migratory phenotype of infiltrating T cells in the meninges of AD patients immunized against Aβ. Specifically, brain infiltrating T cells express cytotoxic genes (e.g. GZMA), activation genes (e.g. CD74 and B2M), and migratory genes (e.g. ITGAL and VCAM1). Additionally, we discovered genetic signatures that distinguish cortical areas cleared of Aβ in immunized AN1792 subjects.Conclusion: We show that active Aβ immunotherapy induces long‐term adaptive immune effects in the AD cortex.