Page 12 - Read Online

Page 8 of 23 Skoreński et al. Rare Dis Orphan Drugs J 2023;2:6 https://dx.doi.org/10.20517/rdodj.2022.21

In 2018, Schulz-Fincke et al. described a synthesis of compound 8 (15) as a potent inhibitor and ABP of
[44]
HNE . This compound belongs to sulfonyloxyphthalimide derivatives and contains coumarin 343 as a
fluorescent tag [Figure 10]. The ability of inhibition was investigated with a spectroscopic assay with the
chromogenic substrate MeOSuc-Ala-Ala-Pro-Val-pNA. This activity-base probe shows selective activity for
HNE with a significant K value of 6.85 ± 0.39 nM and IC value of 0.0189 ± 0.0019 µM. The application of
i
50
these probes enables the detection of NE in neutrophil cell lysate, with the proviso that its selectivity to PR3
is determined .
[44]
PK105b (16) is a fluorescent activity-based probe that contains sulfo Cy5 as a fluorophore, a region of
unnatural specific amino acid, and diphenylphosponate as a warhead [Figure 10]. According to Anderson et
[45]
al., this compound is an example of an irreversible HNE probe . Application of PK105b facilitates the
detection of NE activity in tissue lysates. Unfortunately, this APB was lack of selectivity to HNE, and cross-
reactivity with other serine proteases is also observed .
[45]
Liu et al. posit that NEP (17) is a small-molecule-based near-infrared fluorogenic probe that could be used
as a tool for highly specific and quick detection of HNE in vitro and in vivo [Figure 10]. NEP is a molecule
[46]
based on hemocyanin dye [Figure 10] with the optimum activity observed at pH 7.0 and a temperature of
37 °C in an aqueous solution, under conditions similar to physiological. The application of this tool in vitro
and in vivo was tested using three different cell lines, including RBL-2H3, A549, and MDA-MB-231, as well
as an ALI mice model. The detection limit of this probe is about 29.6 ng/mL. NEP shows high specificity at
the long emission wavelength for HNE (λ = 590 - 650 nm, λ = 660 - 730 nm, λ max = 700 nm) with
em
em
ex
negligible effects of chymotrypsin, trypsin, carboxypeptidase A, and carboxypeptidase B. the application of
this molecule can be helpful in monitoring trafficking exogenous and endogenous NE in cells and living
[46]
organisms, and may serve as a potential tool for diagnosis HNE-related disease .
Bacteria, plants, fungi or venomous animals are known as potential sources of new HNE inhibitors. Many
of these compounds have been described in the literature; unfortunately, most of them have shown low
potency of action, selectivity and stability in physiological conditions [47,48] .

AvKTI is a peptide inhibitor of HNE, as well as trypsin, chymotrypsin, and plasmin, isolated from a spider
T
A r a n e u s ventricosus. h i s p e p t i d e w i t h a s e q u e n c e
KDRCLLPKVTGPCKASLTRYYYDKDTKACVEFIYGGCRGNRNNFKQKDECEKACTDH is the first
described Kunitz-type serine protease inhibitor with antifibrinolytic and anti-elastolytic activity. AvKTI
shows the ability to inhibit HNE with an IC value of 446.93 nM and a K value of 169.07 nM. However, the
i
50
inhibitory activity against plasmin was 44.4-fold stronger than against elastase (IC = 10.07 nM and
50
K = 4.89 nM) .
[49]
i
ShSPI, a natural peptide isolated from venomous Scolopendra hainanum is a typical Kazal-type protease
inhibitor of HNE. This bioactive peptide is composed of 34 amino acids and contains a cysteine-stabilized
α-helix, two-stranded anti-parallel β-sheet, and two disulfide bonds. ShSPI is a non-competitive inhibitor
-8
with a K value of 12.6 ± 2 nM, and its equilibrium dissociation constant K to HNE is 4.2 × 10 . Due to its
D
i
significant stability in physiological conditions after co-incubation with human plasma, ShSPI may be a
[50]
good candidate for the design of new drugs for cardiopulmonary diseases .
Loggerpeptins A-C and molassamide, natural peptides derived from marine cyanobacteria, consist of 19-
membered ring cyclodepsipeptides containing the modified glutamic acid residue 3-amino-6-hydroxy-2-
piperidone [Figure 11]. All peptides have been tested as inhibitors of HNE and compared with Sivelestat