Biology subjects

Feinstein, P.

Publications and source records attributed to Feinstein, P..

12 recordsLinked to original sources

bioRxiv2026

Functional Profiling of a Human Odorant Receptor Using Olfactory Cilia Links its Activation to Odor Quality

The mechanism governing singular odorant receptor (OR) gene choice restricts each olfactory sensory neuron (OSN) to expressing a single OR allele from a repertoire of more than 1,100 receptor genes. Consequently, only a small fraction of OSNs express any given OR, limiting studies of OR function, axonal wiring, and odor coding. Here, we show that multimerizing a 21-bp homeodomain enhancer dramatically increases the probability of receptor choice. We engineered a single-copy Olfr151 minigene carrying a 9x21 enhancer and the human odorant receptor OR10G4, integrated at a genomic site distant from all endogenous OR clusters. This transgene drives singular OR10G4 expression in approximately 75% of OSNs and is accompanied by widespread reductions in endogenous Class I, Class II, and TAAR receptor transcripts and proteins, indicating that cis-regulatory elements govern the probability of OR selection. The abundance of OR10G4-expressing cilia enabled highly sensitive ligand screening using CELIA (Cilia-based Evaluation of Ligands and receptor InterActions). Profiling guaiacol derivatives revealed a strong correspondence among receptor activation, cAMP production, and published human psychophysical responses. Although OR10G4 responds to guaiacol-related odorants, multiple canonical vanilla odorants failed to activate the receptor, arguing against a primary role in vanilla perception. Instead, the lowest EC50 ligands were enriched for compounds human subjects described as smoky. Together, these findings link activation of a single human odorant receptor to a defined perceptual odor-quality dimension and establish a general strategy for decoding the molecular basis of human odor perception.

neuroscience↗

bioRxiv2026

The Olfr151 Odorant Receptor Gene is Resistant to Activation in Embryonic Stem Cells

A single allele of any of the [~]1100 functional mouse odorant receptor (OR) genes is expressed by mature olfactory sensory neurons (mOSNs) through a poorly understood mechanism of singular gene choice. We were interested in developing an expression system to study OR selection in a mouse embryonic stem cell (mESC) carrying an Olfr151-IRES-CRE knock-in and a CRE-recombination-dependent ROSA26-MTMG reporter. Recombination of the ROSA reporter could not be observed after exposing this mESC to thousands of chemical compounds, including 175 compounds known to interfere with epigenetic regulatory processes nor by transfection with high probability Olfr151 promoter minigenes coexpressing CRE. The only two known regulatory elements that control OR promoters are not olfactory specific. Still, our inability to elicit even leaky CRE recombination in mESCs suggests that a specific transcriptional machinery within the OSN lineage is needed to drive OR promoter activation. Author SummaryThe Olfr151 promoter is inactive in mESCs.

neuroscience↗

bioRxiv2024

Rapid Degradation of the Human ACE2 Receptor Upon Binding and Internalization of SARS-Cov-2-Spike-RBD Protein

The SARS-CoV-2 betacoronavirus infects humans through binding the Angiotensin Converting Enzyme 2 (ACE2) protein that lines the nasal cavity and lungs, followed by import into a cell utilizing the Transmembrane Protease, Serine 2 (TMPRSS2) cofactor. ACE2 binding is mediated by an approximately 200-residue portion of the SARS-CoV-2 extracellular spike protein, the receptor binding domain (RBD). Robust interactions are shown using a novel cell-based assay between an RBD membrane tethered-GFP fusion protein and a membrane-bound ACE2-Cherry fusion protein. Several observations were not predicted, including rapid and sustained interactions leading to internalization of the RBD fusion protein into ACE2-expressing cells and rapid downregulation of ACE2-Cherry fluorescence, suggesting that a membrane-associated form of RBD found on the viral coat may have long-term system-wide consequences on ACE2-expressing cells. Targeted mutation in the RBD disulfide Loop 4 led to a loss of internalization for several variants tested. However, a secreted RBD did not cause ACE2 downregulation of ACE2-Cherry fluorescence. Omicron BA.1 and BA.2 variants have altered their dependency on the amino terminus (Nt) of the ACE2 protein. In contrast, the H-CoV-NL63 RBD is only dependent on the ACE2 internal region for binding, leading to the conclusion that the RBD binding surface of ACE2 appears relatively fluid and amenable to internalizing a range of novel variants.

genetics↗

bioRxiv2024

Coronavirus Spike-RBD Variants Differentially Bind to the Human ACE2 Receptor

The SARS-CoV-2 betacoronavirus infects people through binding the human Angiotensin Receptor 2 (ACE2), followed by import into a cell utilizing the Transmembrane Protease, Serine 2 (TMPRSS2) and Furin cofactors. Analysis of the SARS-CoV-2 extracellular spike protein has suggested critical amino acids necessary for binding within a 197-residue portion, the receptor binding domain (RBD). A cell-based assay between a membrane tethered RBD-GFP fusion protein and the membrane bound ACE2-Cherry fusion protein allowed for mutational intersection of both RBD and ACE2 proteins. Data shows Omicron BA.1 and BA.2 variants have altered dependency on the amino terminus of ACE2 protein and suggests multiple epitopes on both proteins stabilize their interactions at the Nt and internal region of ACE2. In contrast, the H-CoV-NL63 RBD is only dependent on the ACE2 internal region for binding. A peptide inhibitor approach to this internal region thus far have failed to block binding of RBDs to ACE2, suggesting that several binding regions on ACE2 are sufficient to allow functional interactions. In sum, the RBD binding surface of ACE2 appears relatively fluid and amenable to bind a range of novel variants.

genetics↗

bioRxiv2022

Commonality of Odorant Receptor Choice Mechanism Revealed by Analysis of a Highly Represented Odorant Receptor Transgene

In the mouse, more than 1,100 odorant receptors (ORs) are expressed in a monogenic and monoallelic fashion, referred to as singular gene expression. Using a 21bp singular-choice enhancer (x21), we radically increase representation of olfactory sensory neurons (OSNs) choosing a 5x21 enhanced OR transgene, but not overexpression of its mRNA on a per cell basis. RNA-sequencing and differential expression analysis identified 425 differentially expressed genes (DEGs). ORs make up 86% of all DEGs, of which 325 have decreased representation and 40 have increased representation. Underrepresented ORs include Class I, Class II and TAAR genes and within each of their respective olfactory bulb domains: DI, DII, and DIII (TAAR) we committedly observe multiple homogeneous glomeruli with an OR1A1-identity. The underrepresentation of endogenous, class-specific ORs across evolutionarily distinct cell types in favor of the expression of the 5x21-OR1A1 transgene argues that a common mechanism of singular gene choice is present for all OR-expressing OSNs.

neuroscience↗

bioRxiv2021

Map-independent representation of an aggression-promoting social cue in the main olfactory pathway

AO_SCPLOWBSTRACTC_SCPLOWWhile the olfactory system is required for proper social behaviors, the molecular basis for how social cues are detected via the main olfactory pathway of mammals is not well-characterized. Trimethylamine is a volatile, sex-specific odor found in adult male mouse urine that selectively activates main olfactory sensory neurons that express trace amine-associated receptor 5 (TAAR5). Here we show that trimethylamine, acting via TAAR5, elicits state-dependent attraction or aversion in male mice and drives inter-male aggression. Genetic knockout of TAAR5 significantly reduces aggression-related behaviors, while adding trimethylamine augments aggressive behavior towards juvenile males. We further show that transgenic expression of TAAR5 specifically in olfactory sensory neurons rescues aggressive behaviors in knockout mice, despite extensive remapping of TAAR5 projections to the olfactory bulb. Our results identify a specific main olfactory input that detects a prominent male-specific odor to induce inter-male aggression in a mammalian species and reveal that apparently innate behavioral responses are independent of patterned glomerular input to the olfactory bulb.

neuroscience↗

bioRxiv2021

Impaired trigeminal control of ingestive behavior in the Prrxl1- / - mouse is associated with a lemniscal-biased orosensory deafferentation

Although peripheral deafferentation studies have demonstrated a critical role for trigeminal afference in modulating the orosensorimotor control of eating and drinking, the central trigeminal pathways mediating that control, as well as the timescale of control, remain to be elucidated. In rodents, three ascending somatosensory pathways process and relay orofacial mechanosensory input: the lemniscal, paralemniscal, and extralemniscal. Two of these pathways (the lemniscal and extralemniscal) exhibit highly structured topographic representations of the orofacial sensory surface, as exemplified by the one-to-one somatotopic mapping between vibrissae on the animals face and barrelettes in brainstem, barreloids in thalamus, and barrels in cortex. Here we use the Prrxl1 knockout mouse model to investigate ingestive behavior deficits associated with disruption of the lemniscal pathway. The Prrxl1 deletion disrupts somatotopic patterning and axonal projections throughout the lemniscal pathway but spares patterning in the extralemniscal nucleus. Our data reveal an imprecise and inefficient ingestive phenotype with deficits that span timescales from milliseconds to months, tightly linking trigeminal input with ingestion, from moment-to-moment consummatory to long term appetitive control. We suggest that ordered assembly of trigeminal sensory information along the lemniscal pathway is critical for the rapid and precise modulation of motor circuits driving eating and drinking action sequences.

neuroscience↗

bioRxiv2021

A Genetic Platform for Functionally Profiling Odorant Receptors Ex Vivo Using Olfactory Cilia.

The molecular basis for odor perception in humans remains an enigma as odorant receptors (ORs) are notoriously difficult to study outside of their native environment. Efforts toward OR expression and functional profiling have been met with limited success due to poor efficiency of in vitro cell surface expression. Olfactory cilia are known to contain all components of the olfactory signal transduction machinery and can be placed into an ex vivo well-plate assay to rapidly measure robust, reproducible odor-specific responses. We now describe the isolation of cilia from mouse nose bioreactors for two human ORs, OR1A1 and OR5AN1, and reveal 10-100 fold more sensitivity compared to previously reported assays. A single animal can produce up to 4,000 384-well assay wells, and isolated olfactory cilia can be stored frozen and thus preserved. This pipeline offers a sensitive, highly scalable ex vivo odor screening platform that opens the door for decoding human olfaction. One Sentence Summaryolfactory-cilia based odor screening platform.

neuroscience↗

bioRxiv2021

High rates of plasmid cotransformation in E. coli overturn the clonality myth and reveal colony development

The concept of DNA transfer between bacteria was put forth by Griffith in 1928. During the dawn of molecular cloning of DNA in the 1980s, Hanahan described how the transformation of DNA plasmids into bacteria would allow for cloning of DNA fragments. Through this foundational work, it is widely taught that a typical transformation produces clonal bacterial colonies. Using low concentrations of several plasmids that encode different fluorescent proteins, under the same selective antibiotic, we show that E. coli bacteria readily accept multiple plasmids, resulting in widespread aclonality and reveal a complex pattern of colony development. Cotransformation of plasmids occurs by either CaCl2 or by electroporation methods. A bacterium rod transformed with three plasmids - each expressing a high level of a unique fluorescent protein - and replated on agar, appears to reassign a random number of the three fluorescent plasmids to its daughter cell during cell division. The potential to simultaneously follow multiple lineages of clonally related bacteria in a bacteria colony would allow for mosaic analysis of gene function. We show that clonally related bacterium rods self-organize in a fractal growth pattern and can remain linked during colony development revealing a potential target against microbiota growth.

molecular biology↗

bioRxiv2020

Transcriptional profiling reveals TRPM5-expressing cells involved in viral infection in the olfactory epithelium

BackgroundUnderstanding viral infection of the olfactory epithelium is essential because the olfactory nerve is an important route of entry for viruses to the central nervous system. Specialized chemosensory epithelial cells that express the transient receptor potential cation channel subfamily M member 5 (TRPM5) are found throughout the airways and intestinal epithelium and are involved in responses to viral infection. ResultsHerein we performed deep transcriptional profiling of olfactory epithelial cells sorted by flow cytometry based on the expression of mCherry as a marker for olfactory sensory neurons and for eGFP in OMP-H2B::mCherry/TRPM5-eGFP transgenic mice (Mus musculus). We find profuse expression of transcripts involved in inflammation, immunity and viral infection in TRPM5-expressing microvillous cells. ConclusionOur study provides new insights into a potential role for TRPM5-expressing microvillous cells in viral infection of the olfactory epithelium. We find that, as found for solitary chemosensory cells (SCCs) and brush cells in the airway epithelium, and for tuft cells in the intestine, the transcriptome of TRPM5-expressing microvillous cells indicates that they are likely involved in the inflammatory response elicited by viral infection of the olfactory epithelium.

neuroscience↗

bioRxiv2019

Single-Cell, Human Sperm Transcriptomes and Variants from Fathers of Autistic and Healthy Children

The human sperm is one of the smallest cells in the body, but also one of the most important, as it serves as the entire paternal genetic contribution to a child. This is especially relevant for diseases such as Autism Spectrum Disorders (ASD), which have been correlated with advance paternal age. Historically, most studies of sperm have focused on the assessment of a bulk sperm, wherein millions of individual sperm are present and only high-frequency variants can be detected. Using 10X Chromium single cell sequencing technology, we have assessed the RNA from >65,000 single sperm cells across 6 donors (scsperm-RNA-seq), including two of whom have autistic children and four that do not. Using multiple RNA-seq methods for differential expression and variant analysis, we found clusters of sperm mutations in each donor that are indicative of the sperm being produced by different stem cell pools. Moreover, by comparing the two groups, we have found expression changes that can separate out the two sets of donors. Finally, through our novel variant calling from single-cell RNA-seq methods, we have shown that we can detect mutation rates in sperm from ASD donors that is distinct from the controls, highlighting this method as a new means to characterize ASD risk.

genomics↗

bioRxiv2018

Single olfactory receptors set odor detection thresholds

In many species, survival depends on olfaction, yet the mechanisms that underlie olfactory sensitivity are not well understood. Here, we examine how a conserved subset of olfactory receptors, the trace amine-associated receptors (TAARs) determine odor detection thresholds of mice to amines. We find that deleting all TAARs, or even single TAARs, results in significant odor detection deficits. This finding is not limited to TAARs, as the deletion of a canonical odorant receptor reduced behavioral sensitivity to its preferred ligand. Remarkably, behavioral threshold is set solely by the most sensitive receptor, with no contribution from other highly sensitive receptors. In addition, increasing the number of sensory neurons (and glomeruli) expressing a threshold-determining TAAR does not improve detection, indicating that sensitivity is not limited by the typical complement of sensory neurons. Our findings demonstrate that olfactory thresholds are set by the single highest affinity receptor, and suggest that TAARs are evolutionarily conserved because they determine the sensitivity to a class of biologically relevant chemicals.

neuroscience↗