Marco Orecchioni, PhD

We are an international, multidisciplinary team fascinated by an unexpected discovery: macrophages and monocytes carry functional Olfactory Receptors (ORs), the largest family of Gprotein鈥揷oupled receptors (GPCRs), the same receptor family that lets us smell.

These immune 鈥渘oses鈥� detect diet-derived aldehydes, oxidative stress byproducts, microbial metabolites, and even tumor volatiles compounds, rewiring inflammation that drives atherosclerosis, metabolic disorders, sepsis and cancer. By pairing cutting-edge single-cell 鈥榦mics with in vivo models and cellular and molecular biology, we aim to translate chemosensory immunology into first-in-class GPCR-based therapeutics.

Marco Orecchioni, PhD

Assistant Professor
Immunology Center of Georgia

Contact Us

Immunology Center of Georgia

1410 Laney Walker Blvd, CN 4092

706-729-2204

morecchioni@augusta.edu

What We Do

Marco lab team

A central goal of the Orecchioni鈥疞ab is to uncover how olfactory receptors modulate innate immune behavior in disease, and to translate these insights into therapeutic strategies. We integrate CRISPR-engineered reporter mice, high-dimensional flow cytometry, CyTOF, 鈥渙mics鈥� technologies, and in vivo and in vitro assays and imaging to follow OR-expressing monocytes and macrophages from blood to tissue and to chart the signaling, metabolic, and transcriptional programs they modulate.

Four projects illustrate our approach:

Project鈥�1 | OxidizedLDL sensing in atherosclerosis.
Inflammatory cues (LPS, oxLDL) upregulate Olfr2/OR6A2 on monocytes and macrophages. Olfr2 detects the lipid peroxidation aldehyde octanal, triggers NLRP3 inflammasome activation, and fuels IL1尾 release. Using conditional knockouts, pharmacologic antagonists, and competitive adoptive transfer, we test whether Olfr2 orchestrates monocyte homing, lipid accumulation, and formation of proinflammatory foamy macrophages that accelerate plaque progression.

Project鈥� 2 | Octanal, oxidative stress, and inflammation.

We are investigating whether endothelial dysfunction arising from oxidative stress, lipid peroxidation, and ferroptosis leads to the liberation of octanal. We further examine how circulating octanal engages Olfr2/OR6A2 receptors on monocytes to promote chemotaxis, extravasation, and modulation of inflammatory responses. Parallel metabolomic and lipid peroxidation assays are employed to identify the enzymes responsible for octanal production and the pathways that mediate its detoxification, thereby revealing potential biomarkers and therapeutic targets.

Project 鈥�3 | Olfr2 signaling and function in melanoma immunity.
Melanoma tumors release octanal and other metabolites that activate Olfr2 on tumor-infiltrating monocytes/macrophages. Singlecell RNAseq, CyTOF, and spectral flow cytometry reveal that this axis boosts macrophage inflammasome activity and enhances CD8鈦衡€疶cell priming, correlating with better checkpoint blockade responses. A new myeloid-specific Olfr2 knockout dissects how OR activation reshapes the tumor microenvironment and tests small molecule agonists as adjuvants to immunotherapy.

Project鈥�4 | Human translation & discovery of new immune ORs.
We are directly translating murine Olfr2 biology to its human ortholog, OR6A2, validating receptor expression, signaling, and ligand profiles in primary human monocytes/macrophages and carotidplaque specimens. In parallel, ligand-screening and single-cell multi-omics screens are uncovering previously unrecognized functional ORs in human and mouse innate immune cells, expanding the repertoire of chemosensory GPCRs we can target across cardiovascular, metabolic, and oncologic diseases.