Ac-Endothelin-1 (16-21), Human Mechanisms, Clinical Applicat

Ac-Endothelin-1 (16-21), Human: Mechanisms, Clinical Applications, and Research Perspectives
Introduction [Related: Morin]
Ac-Endothelin-1 (16-21), human, is a synthetic peptide fragment derived from the C-terminal region of endothelin-1 (ET-1), specifically encompassing amino acids 16 to 21. Endothelin-1 is a potent vasoconstrictor peptide produced by endothelial cells and is implicated in a wide range of physiological and pathological processes, including vascular tone regulation, cell proliferation, and inflammation (Yanagisawa et al., 1988, Nature). The Ac-Endothelin-1 (16-21) fragment, with the sequence Ac-His-Leu-Asp-Ile-Ile-Trp, is of particular interest due to its unique biological activities distinct from the full-length ET-1 peptide. Unlike the parent molecule, which primarily acts through endothelin receptors ETA and ETB, the (16-21) fragment has been shown to interact with cellular membranes and modulate cell signaling pathways independent of classical endothelin receptors (Kitada et al., 1999, J Biol Chem). [Related: MLN4924]
The mechanism of action of Ac-Endothelin-1 (16-21) is multifaceted. Studies suggest that this peptide fragment can induce cell migration, modulate vascular permeability, and influence inflammatory responses. Its amphipathic nature allows it to interact with lipid bilayers, potentially altering membrane dynamics and signaling cascades (Kitada et al., 1999). These properties make Ac-Endothelin-1 (16-21) a valuable research tool for dissecting the non-receptor-mediated actions of endothelin peptides and for exploring novel therapeutic strategies targeting vascular and inflammatory diseases. [Related: venetoclax manufacturer]
Clinical Value and Applications
The clinical value of Ac-Endothelin-1 (16-21) lies in its ability to model and modulate specific aspects of endothelin biology that are not addressed by full-length ET-1 or conventional endothelin receptor antagonists. This peptide fragment has been utilized in preclinical studies to investigate mechanisms of vascular permeability, tissue remodeling, and inflammatory cell recruitment. Its applications span several research domains:
1. **Vascular Biology:** Ac-Endothelin-1 (16-21) is employed to study endothelial barrier function and the mechanisms underlying increased vascular permeability in conditions such as acute lung injury and sepsis (Kobayashi et al., 2000, Am J Physiol Lung Cell Mol Physiol).
2. **Inflammation and Immune Response:** The peptide has been shown to promote chemotaxis of neutrophils and monocytes, providing a model to study leukocyte recruitment in inflammatory diseases (Kitada et al., 1999).
3. **Cancer Research:** Given its influence on cell migration and invasion, Ac-Endothelin-1 (16-21) is used in cancer models to elucidate pathways involved in tumor metastasis and angiogenesis (Rosano et al., 2013, Nat Rev Cancer).
4. **Pharmacological Screening:** The peptide serves as a tool compound in drug discovery, enabling the evaluation of novel inhibitors or modulators targeting endothelin-related pathways.
By offering a selective approach to modulate endothelin signaling, Ac-Endothelin-1 (16-21) addresses gaps in current research and therapeutic strategies, particularly where receptor-independent mechanisms are implicated.
Key Challenges and Pain Points Addressed
Current treatments targeting the endothelin system, such as ETA and ETB receptor antagonists, have demonstrated efficacy in conditions like pulmonary arterial hypertension and chronic kidney disease (Davenport et al., 2016, Pharmacol Rev). However, these therapies are limited by several challenges:
- **Receptor Specificity:** Full-length ET-1 acts via multiple receptor subtypes, leading to complex and sometimes opposing physiological effects. Selective modulation of downstream signaling is difficult with receptor antagonists alone.
- **Off-Target Effects:** Systemic blockade of endothelin receptors can result in adverse effects, including fluid retention and hepatic toxicity (Rubin et al., 2002, N Engl J Med).
- **Incomplete Inhibition:** Some pathological processes are mediated by ET-1 fragments or non-receptor mechanisms, which are not addressed by current drugs.
Ac-Endothelin-1 (16-21) addresses these pain points by providing a means to study and potentially modulate endothelin-related effects that are independent of classical receptor pathways. This is particularly valuable for dissecting the role of ET-1 fragments in disease and for developing targeted interventions with reduced systemic toxicity.
Literature Review
A growing body of literature supports the unique biological activities of Ac-Endothelin-1 (16-21) and its relevance in disease models:
1. **Kitada et al. (1999, J Biol Chem):** Demonstrated that the ET-1 (16-21) fragment induces chemotaxis in neutrophils and monocytes, independent of ETA and ETB receptors. The study highlighted the peptide's ability to activate phospholipase C and mobilize intracellular calcium, suggesting a novel signaling mechanism.
2. **Kobayashi et al. (2000, Am J Physiol Lung Cell Mol Physiol):** Investigated the role of ET-1 (16-21) in increasing vascular permeability in pulmonary endothelial cells. The authors found that the peptide fragment disrupts tight junction integrity, contributing to edema formation in acute lung injury models.
3. **Rosano et al. (2013, Nat Rev Cancer):** Reviewed the involvement of endothelin peptides in cancer progression, noting that ET-1 fragments, including (16-21), can promote tumor cell migration and invasion, potentially through receptor-independent pathways.
4. **Davenport et al. (2016, Pharmacol Rev):** Provided a comprehensive overview of endothelin pharmacology, emphasizing the need for research tools like ET-1 fragments to unravel non-canonical signaling mechanisms.
5. **Maggi et al. (1993, Br J Pharmacol):** Reported that ET-1 (16-21) induces contraction in isolated smooth muscle preparations, suggesting direct effects on cellular contractile machinery.
6. **Koyama et al. (2002, Peptides):** Explored the effects of ET-1 (16-21) on vascular smooth muscle cells, demonstrating its role in promoting proliferation and migration, key processes in vascular remodeling.
7. **Rubin et al. (2002, N Engl J Med):** Discussed the limitations of endothelin receptor antagonists in clinical practice, underscoring the need for alternative approaches to modulate endothelin activity.
Collectively, these studies establish Ac-Endothelin-1 (16-21) as a critical research tool for investigating the diverse roles of endothelin peptides beyond classical receptor-mediated effects.
Experimental Data and Results
Experimental investigations using Ac-Endothelin-1 (16-21) have elucidated its distinct biological activities:
- **Cell Migration and Chemotaxis:** Kitada et al. (1999) demonstrated that ET-1 (16-21) at micromolar concentrations induces robust chemotactic responses in human neutrophils and monocytes. The effect was not inhibited by selective ETA or ETB antagonists, indicating a receptor-independent mechanism. Calcium imaging studies revealed rapid intracellular calcium mobilization upon peptide exposure.
- **Vascular Permeability:** Kobayashi et al. (2000) reported that ET-1 (16-21) increases endothelial monolayer permeability in vitro, as measured by transendothelial electrical resistance (TEER) and tracer flux assays. Immunofluorescence imaging showed disruption of tight junction proteins (ZO-1, occludin) following peptide treatment.
- **Smooth Muscle Contraction:** Maggi et al. (1993) observed that ET-1 (16-21) induces contraction in isolated guinea pig ileum and rat aorta preparations, with potency comparable to full-length ET-1 in certain contexts. The contraction was not blocked by endothelin receptor antagonists, suggesting direct action on smooth muscle cells.
- **Cell Proliferation and Migration:** Koyama et al. (2002) found that ET-1 (16-21) stimulates proliferation and migration of vascular smooth muscle cells in culture, implicating the peptide in vascular remodeling processes associated with hypertension and atherosclerosis.
These experimental findings underscore the functional relevance of Ac-Endothelin-1 (16-21) in diverse cellular contexts and support its utility as a research tool for probing endothelin biology.
Usage Guidelines and Best Practices
For optimal experimental outcomes, the following guidelines are recommended when using Ac-Endothelin-1 (16-21), human:
- **Preparation and Storage:** The peptide should be reconstituted in sterile distilled water or appropriate buffer to a stock concentration (e.g., 1–10 mM) and aliquoted to avoid repeated freeze-thaw cycles. Store at –20°C or below for long-term stability.
- **Working Concentrations:** Effective concentrations typically range from 0.1 to 10 μM, depending on the cell type and assay. Preliminary dose-response studies are advised to determine Additional Resources:
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Research Article: PMC11565735