ARA-290

<p><strong>ARA-290 (Cibinetide)</strong> is an 11-amino-acid synthetic peptide engineered from the three-dimensional helical structure of erythropoietin (EPO), specifically designed to retain EPO tissue-protective signaling capacity while eliminating its erythropoietic (red blood cell-stimulating) activity. The compound acts selectively on the innate repair receptor (IRR), a non-erythropoietic EPO receptor complex expressed on neurons, immune cells, and peripheral tissues. This mechanistic separation from the classical EPOR/beta-common receptor pathway makes ARA-290 a precision research tool for investigating tissue-protective and anti-inflammatory EPO signaling in isolation from hematopoietic side effects.</p>

<h2>Mechanism of Action</h2>

<h3>Innate Repair Receptor (IRR) Selectivity</h3>

<p>The classical EPO receptor complex responsible for erythropoiesis consists of a homodimer of EPOR subunits. The tissue-protective, anti-apoptotic, and anti-inflammatory effects of EPO are mediated by a distinct heteromeric receptor complex consisting of EPOR + beta common chain (betaC, or CD131) — the innate repair receptor. ARA-290 is engineered with an amino acid sequence corresponding to EPO helix B, the region of the EPO protein that preferentially engages the IRR rather than the erythropoietic homodimer. This selectivity is critical: full-length EPO used in hematopoietic applications raises red blood cell counts and raises thrombotic risk, confounders that are absent from ARA-290 experiments.</p>

<h3>Neuroprotective and Anti-Inflammatory Signaling</h3>

<p>IRR activation by ARA-290 has been linked to downstream suppression of NF-kB-driven inflammatory cytokine production, activation of JAK2/STAT3 anti-apoptotic signaling in neurons, and modulation of macrophage polarization toward reparative phenotypes. In peripheral nervous system models, these effects translate into survival of damaged small-diameter sensory nerve fibers and promotion of axonal regrowth — the cellular basis for corneal nerve fiber density changes observed in clinical studies.</p>

<h3>Metabolic Tissue Protection</h3>

<p>In metabolic models, ARA-290 has been studied for protective effects on pancreatic islet beta cells under inflammatory stress, and for modulation of peripheral insulin sensitivity through IRR-expressing immune cells in adipose and hepatic tissue. The compound does not directly stimulate insulin secretion; rather, it is studied for reducing the inflammatory microenvironment that impairs insulin signaling, making it relevant to metabolic neuropathy research models.</p>

<h2>Clinical and Preclinical Research Highlights</h2>

<p>Two major published research lines define the ARA-290 literature:</p>

<ul> <li><strong>Sarcoidosis-associated neuropathy:</strong> In a placebo-controlled study, Culver and colleagues (PMID 28475703) demonstrated that 28 days of cibinetide treatment produced significant improvement in corneal nerve fiber density in sarcoidosis patients with small fiber neuropathy, providing an objective morphological marker of nerve regeneration alongside patient-reported neuropathic symptom improvement. This remains one of the most clearly documented demonstrations of peripheral nerve regeneration in a clinical context using an EPO-derived peptide.</li> <li><strong>Metabolic neuropathy:</strong> Brines and colleagues (PMID 25387363) conducted a proof-of-concept study in subjects with impaired glucose regulation and small fiber neuropathy, demonstrating improvements in HbA1c, reduced neuropathic symptom scores, and changes in corneal nerve fiber measurements over an 8-week study period — suggesting IRR-mediated protective effects on both metabolic and neurological endpoints.</li> </ul>

<h2>Research Applications</h2>

<ul> <li><strong>Small fiber neuropathy models</strong> — corneal confocal microscopy as an objective, non-invasive surrogate for peripheral nerve density; intraepidermal nerve fiber density (IENFD) measurement; neurite outgrowth assays in dorsal root ganglion (DRG) neurons</li> <li><strong>Innate repair receptor pharmacology</strong> — IRR ligand binding studies, betaC/EPOR complex characterization, downstream JAK2/STAT3 and NF-kB pathway studies in neurons and immune cells</li> <li><strong>Neuroinflammation research</strong> — macrophage polarization studies (M1 to M2 shift), microglial activation models, pro-inflammatory cytokine suppression (IL-1β, TNF-α, IL-6) in neural tissue</li> <li><strong>Sarcoidosis and granulomatous disease models</strong> — cell culture and animal models of granulomatous inflammation, macrophage biology in granuloma formation, anti-inflammatory small molecule or peptide strategies</li> <li><strong>EPO pathway dissection</strong> — studies requiring separation of EPO erythropoietic effects from EPO tissue-protective effects, receptor subtype-selective pharmacology, EPO-mimetic compound SAR studies</li> <li><strong>Metabolic neuropathy and peripheral nerve regeneration</strong> — diabetic peripheral neuropathy models, glucose toxicity-induced neuronal damage, beta cell cytoprotection under inflammatory stress</li> <li><strong>Autonomic nervous system research</strong> — studies examining autonomic fiber populations (small unmyelinated C-fibers and thinly myelinated Adelta fibers) in autonomic dysfunction models</li> </ul>

<h2>Market Context</h2>

<p>ARA-290 is a specialized research peptide reflecting its clinical-stage history (phase 2 trials completed). Peptides.SO tracks <strong>47 active supplier listings</strong> with pricing ranging from near $0 (promotional or sample-size offerings) to approximately $856 per listing, with a platform average near $71. The pricing variation reflects the range of vial sizes available (commonly 0.5mg to 10mg), supplier quality tiers, and whether the product is lyophilized (powder) or pre-dissolved. As a shorter peptide (11 amino acids) compared to BPC-157 (15) or IGF-1LR3 (83), ARA-290 synthesis costs are relatively contained, but premium pricing in specialized vendors reflects the clinical research context and demand from neuropathy researchers specifically.</p>

<p>Note: the $0 minimum in platform listings typically represents a free-sample or bundle-inclusion listing rather than a zero-price commercial offer. Filter by meaningful price thresholds when running cost comparisons.</p>

<h2>Frequently Asked Questions</h2>

<p><strong>What distinguishes ARA-290 from full-length EPO as a research tool?</strong><br/> Full-length EPO activates both the erythropoietic EPOR homodimer (increasing red blood cell production, raising hematocrit, and increasing thrombotic risk) and the tissue-protective IRR heterodimer. ARA-290 selectively engages only the IRR, making it suitable for experiments where erythropoietic side effects would confound results or create ethical constraints. For studying purely tissue-protective EPO signaling without hematopoietic confounders, ARA-290 is the preferred research tool.</p>

<p><strong>Is corneal confocal microscopy the standard readout for ARA-290 neuroprotection studies?</strong><br/> In published clinical studies, corneal nerve fiber density (CNFD) measured by corneal confocal microscopy has been used as the primary objective morphological endpoint because the cornea is the most densely innervated tissue in the human body and corneal nerves are accessible non-invasively. In rodent models, intraepidermal nerve fiber density (IENFD) from skin punch biopsies is commonly used. Both metrics serve as proxies for peripheral sensory nerve fiber abundance.</p>

<p><strong>What is the standard reconstitution approach for ARA-290 in cell culture studies?</strong><br/> ARA-290 is water-soluble and typically reconstituted in sterile PBS or cell-culture-grade water. Stock solutions at 1 mM (approximately 1.4 mg/mL given an MW of ~1,408 Da for the 11-mer) stored at −80°C are stable for research use. Working dilutions in serum-free media are made immediately before use to prevent peptide degradation.</p>

<p><strong>Is ARA-290 related to other EPO-mimetic peptides?</strong><br/> Yes, ARA-290 belongs to a class of EPO-derived tissue-protective peptides including ARA-290 analogs (cibinetide), EMP peptides (EPO mimetic peptides), and helix-B surface peptide (HBSP). Each variant is engineered from different structural regions of EPO with varying degrees of IRR vs. EPOR selectivity, making them useful comparative tools in EPO receptor biology research.</p>

<h2>Cited Research</h2>

<ul> <li>Brines M, et al. "ARA 290, a nonerythropoietic peptide engineered from erythropoietin, improves metabolic control and neuropathic symptoms in patients with type 2 diabetes." <em>Mol Med.</em> 2015. PMID: <a href="https://pubmed.ncbi.nlm.nih.gov/25387363/" rel="noopener">25387363</a></li> <li>Culver DA, et al. "Cibinetide Improves Corneal Nerve Fiber Abundance in Patients With Sarcoidosis-Associated Small Nerve Fiber Loss and Neuropathic Symptoms." <em>Invest Ophthalmol Vis Sci.</em> 2017. PMID: <a href="https://pubmed.ncbi.nlm.nih.gov/28475703/" rel="noopener">28475703</a></li> <li>Brines M, Cerami A. "The receptor that tames the innate immune response." <em>Mol Med.</em> 2012. PMID: <a href="https://pubmed.ncbi.nlm.nih.gov/22576523/" rel="noopener">22576523</a></li> <li>van Velzen M, et al. "Treatment of patients with neuropathic pain with ARA290, an erythropoietin-derived peptide." <em>J Pain Res.</em> 2014. PMID: <a href="https://pubmed.ncbi.nlm.nih.gov/24971023/" rel="noopener">24971023</a></li> </ul>

<p><em>For research purposes only. ARA-290/cibinetide is not approved for therapeutic use in humans or animals, is not a drug or dietary supplement, and has not been evaluated by the FDA or equivalent authority for safety or efficacy outside controlled research settings. All experimental use must comply with applicable institutional and regulatory guidelines.</em></p>