Biology subjects

Lerner, T.

Publications and source records attributed to Lerner, T..

7 recordsLinked to original sources

bioRxiv2025

Overexpression of alpha synuclein in Midbrain Dopamine Neurons Reduces Dopamine Release Without Cell Loss and Drives Mild Motor Deficits in Mice

It has proven challenging to faithfully recapitulate the key pathological, physiological, and behavioral features of Parkinsons Disease (PD) in animals. Here we used adeno-associated virus (AAV) vectors to achieve cell type-specific overexpression of wild-type human -synuclein (syn) and a fluorophore (mCherry) in midbrain dopamine neurons to model PD in mice. We found that AAVs drove selective expression of both syn and mCherry in midbrain dopamine neurons. In conjunction with approximately 2-fold overexpression of syn, we found several histopathological markers of PD-like pathology, including progressive accumulation of phosphorylated and aggregated syn, ubiquitin, and a reduction in the expression of tyrosine hydroxylase, without overt cell loss. In parallel, syn overexpression drove a profound loss of evoked dopamine release, without a substantive change in the intrinsic properties of dopamine neurons, nor in striatal dopamine content. Finally, syn overexpression led to mild locomotor deficits. Together, these findings suggest that moderate syn overexpression can mimic some aspects of premotor and early symptomatic phases of PD, including markers of Lewy Body-like pathology and functional loss of evoked dopamine release. This model may be useful for investigating cellular and circuit mechanisms related to PD pathogenesis and progression.

neuroscience↗

bioRxiv2023

Boosting class II HLA epitope presentation to T cells with endoplasmic reticulum transmembrane domain fusion proteins

Antigen processing and presentation are crucial for T-cell receptor engagement and potent adaptive immune responses. While establishing an antigen presentation system to identify TCR-epitope pairs from large libraries of genetically templated, ectopically expressed antigens, we observed a longitudinal suppression of antigen processing in B cells, which we call antigen processing attenuation (APA). Beyond its potential role in regulating B cell-enforced peripheral tolerance, APA represents a bottleneck to sustained antigen presentation in screening and vaccination approaches. To overcome APA we screened several pathways which might enhance processing. Notably, we identified several sequences derived from transmembrane domains (TM) of endoplasmic reticulum-resident proteins which promote sustained minigene-encoded antigen presentation. In particular, the first TM domain of SYT6, a protein associated with synaptic vesicles, greatly enhances processing and ameliorates APA. These findings suggest a new entry point into antigen processing pathways, enabling the discovery of novel immune epitopes and improving T-cell based immunization strategies.

molecular biology↗

bioRxiv2023

T-FINDER: A highly sensitive, pan-HLA platform for functional T cell receptor and ligand discovery

Effective, unbiased, high-throughput methods to functionally identify both class II and class I HLA-presented T cell epitopes and their cognate T cell receptors (TCRs) are essential for and prerequisite to diagnostic and therapeutic applications, yet remain underdeveloped. Addressing this bottleneck, we established T-FINDER (T cell Functional Identification and (Neo)-antigen Discovery of Epitopes and Receptors), a platform that rapidly deconvolutes CD4 and CD8 TCR reactivities to targets physiologically processed and presented by an individuals unmanipulated, complete HLA haplotype. By using a highly sensitive TCR signaling reporter capable of detecting even low-affinity TCR:ligand interactions, T-FINDER not only robustly identifies unknown peptide:HLA ligands from complex antigen libraries, but also rapidly screens and functionally validates the specificity of complex TCR libraries against known or predicted targets. To demonstrate its pan-HLA presentation capacity, we apply the platform to multiple TCR-based applications, including glioma, celiac disease, and rheumatoid arthritis, providing unique biological insights and showcasing T-FINDERs potency and versatility.

immunology↗

bioRxiv2023

Neoepitope-specific vaccination of a patient with diffuse midline glioma targeting H3K27M induces polyclonal B and T cell responses across diverse HLA alleles

H3K27M, a driver mutation with T- and B-cell neoepitope characteristics, defines an aggressive subtype of diffuse glioma with poor survival. We functionally dissect the immune response of one patient who was treated with an H3K27M peptide vaccine and subsequently entered complete remission. The vaccine robustly expanded class II HLA-restricted peripheral H3K27M-specific T cells. Using functional assays, we characterized 34 clonally unique H3K27M-reactive T cell receptors and identified critical, conserved motifs in their CDR3 regions. Using detailed HLA mapping, we further demonstrate that diverse HLA-DQ, and -DR alleles present immunogenic H3K27M epitopes. Furthermore, we identified and profiled H3K27M-reactive B cell receptors from activated B cells in the cerebrospinal fluid. Our results uncover the breadth of the adaptive immune response against a shared clonal neoantigen across multiple HLA allelotypes and support the use of class II-restricted peptide vaccines to stimulate tumor-specific T and B cells harboring receptors with therapeutic potential.

cancer biology↗

bioRxiv2021

GuPPy, a Python toolbox for the analysis of fiber photometry data

Fiber photometry (FP) is an adaptable method for recording in vivo neural activity in freely behaving animals. It has become a popular tool in neuroscience due to its ease of use, low cost, the ability to combine FP with freely moving behavior, among other advantages. However, analysis of FP data can be a challenge for new users, especially those with a limited programming background. Here, we present Guided Photometry Analysis in Python (GuPPy), a free and open-source FP analysis tool. GuPPy is provided as a Jupyter notebook, a well-commented interactive development environment (IDE) designed to operate across platforms. GuPPy presents the user with a set of graphic user interfaces (GUIs) to load data and provide input parameters. Graphs produced by GuPPy can be exported into various image formats for integration into scientific figures. As an open-source tool, GuPPy can be modified by users with knowledge of Python to fit their specific needs.

neuroscience↗

bioRxiv2020

Parvalbumin+ and Npas1+ Pallidal Neurons Have Distinct Circuit Topology and Function

The external globus pallidus (GPe) is a critical node within the basal ganglia circuit. Phasic changes in the activity of GPe neurons during movement and their alterations in Parkinsons disease (PD) argue that the GPe is important in motor control. PV+ neurons and Npas1+ neurons are the two principal neuron classes in the GPe. The distinct electrophysiological properties and axonal projection patterns argue that these two neuron classes serve different roles in regulating motor output. However, the causal relationship between GPe neuron classes and movement remains to be established. Here, by using optogenetic approaches in mice (both males and females), we showed that PV+ neurons and Npas1+ neurons promoted and suppressed locomotion, respectively. Moreover, PV+ neurons and Npas1+ neurons are under different synaptic influences from the subthalamic nucleus (STN). Additionally, we found a selective weakening of STN inputs to PV+ neurons in the chronic 6-hydroxydopamine lesion model of PD. This finding reinforces the idea that the reciprocally connected GPe-STN network plays a key role in disease symptomatology and thus provides the basis for future circuit-based therapies. Significance StatementThe external pallidum is a key, yet an understudied component of the basal ganglia. Neural activity in the pallidum goes awry in neurological diseases, such as Parkinsons disease. While this strongly argues that the pallidum plays a critical role in motor control, it has been difficult to establish the causal relationship between pallidal activity and motor (dys)function. This was in part due to the cellular complexity of the pallidum. Here, we showed that the two principal neuron types in the pallidum have opposing roles in motor control. In addition, we described the differences in their synaptic influence. Importantly, our research provides new insights into the cellular and circuit mechanisms that explain the hypokinetic features of Parkinsons disease.

neuroscience↗

bioRxiv2019

MultiEditR: An easy validation method for detecting and quantifying RNA editing from Sanger sequencing

RNA editing is the base change that results from RNA deamination by two predominant classes of deaminases; the APOBEC family and the ADAR family. Respectively, deamination of nucleobases by these enzymes are responsible for endogenous editing of cytosine to uracil (C-to-U) and adenosine to inosine (A-to-I). RNA editing is known to play an essential role both in maintaining normal cellular function, as well as altered cellular physiology during oncogenesis and tumour progression. Analysis of RNA editing in these important processes, largely relies on RNA-seq technology for the detection and quantification of RNA editing sites. Despite the power of these technologies, multiple sources of error in detecting and measuring base editing still exist, therefore additional validation and quantification of editing through Sanger sequencing is still required for confirmation of editing. Depending on the number of RNA editing sites that are of interest, this validation step can be both expensive and time-consuming. To address this need we developed the tool MultiEditR which provides a simple, and cost-effective method of detecting and quantifying RNA editing form Sanger sequencing. We expect that MultiEditR will foster further discoveries in this rapidly expanding field.

bioinformatics↗