Peptide RP-832c is a novel synthetic analogue of a naturally occurring Host Defense Peptide (HDP), designed to target the CD206 receptor on M2-polarized macrophages. This peptide plays a crucial role in mediating innate immune responses and has shown promising results in reducing pro-fibrotic cytokines in various models of lung fibrosis.

Activated M2-polarized macrophages are known drivers of pulmonary fibrosis in conditions like Idiopathic Pulmonary Fibrosis (IPF). RP-832c binds selectively to the CD206 receptor on these macrophages, leading to a time-dependent decrease in CD206 expression and an increase in M1-macrophage markers such as TNF-α. This action mechanism suggests that RP-832c can modulate macrophage activation states, shifting them from a pro-fibrotic M2-like phenotype to a potentially less harmful M1-like phenotype.

The efficacy of RP-832c has been tested in vitro using bone marrow-derived macrophages (BMDM) and in vivo using a murine model of bleomycin (BLM)-induced early-stage pulmonary fibrosis. In these models, RP-832c demonstrated a significant reduction in fibrosis in a dose-dependent manner, decreased expression of pro-fibrotic markers like CD206, TGF-β1, α-SMA, and inflammatory cytokines such as TNF-α, IL-6, IL-10, IFN-γ, CXCL1/2. Moreover, RP-832c's effects on reducing lung fibrosis were comparable or even superior to FDA-approved drugs like Nintedanib and Pirfenidone, without exhibiting any significant toxicity at the tested doses.

RP-832c represents a potential new avenue for treating pulmonary fibrosis, targeting the activated M2-like macrophages that are central to the disease's progression. Its ability to modify macrophage phenotype and reduce fibrosis without significant toxicity highlights its therapeutic potential for patients with pulmonary fibrosis

• Ghebremedhin A, Salam AB, Adu-Addai B, Noonan S, Stratton R, Ahmed MSU, Khantwal C, Martin GR, Lin H, Andrews C, Karanam B, Rudloff U, Lopez H, Jaynes J, Yates C. A Novel CD206 Targeting Peptide Inhibits Bleomycin-Induced Pulmonary Fibrosis in Mice. Cells. 2023 Apr 26;12(9):1254. doi: 10.3390/cells12091254. PMID: 37174654; PMCID: PMC10177262.

三氟乙酸（TFA）是一种强酸，常用于从固相树脂中裂解合成的多肽，也可用于提高多肽纯化步骤中的HPLC性能。默认情况下，定制的多肽是以冻干的TFA盐的形式交付的，其中TFA的含量可能高达10-45%。

定制多肽中的TFA可能会导致后续检测数据出现无法解释的差异。例如，nM浓度的TFA已被证明会干扰细胞实验，在某些情况下会抑制细胞增殖，而在其他情况下会增加细胞活力。

TFA去除服务推荐用于:

• 将用于细胞试验的多肽
• 将被用作原料药或制成品的多肽
• 含有大量碱性残基的亲水多肽

干品多肽的重量中不仅仅包含多肽，还包含有一些非肽的组份，如水、被吸收的溶剂、配位离子和盐等。肽的净含量是指肽在其中的重量百分比，这个百分比的数值范围很大，可能从50%到90%，取决于纯度、序列以及合成和纯化的方法，不要将肽的净含量和肽的纯度混为一谈，他们是两个完全不同的概念。纯度通常是通过HPLC测定的。纯度定义的是多肽样品中含正确序列的组分的百分比，而肽的净含量是指样品中肽类物质相对于总物质所占的百分比，肽的净含量通常是氨基酸组分分析或紫外分光法测定的，这个信息主要是在一些对肽的浓度很敏感的实验中，对计算肽的浓度是很重要的。