The current study provides a new strategy for effectively and rapidly
analyzing the active ingredients of herbal medicines based on the public
bioinformatics platforms, which fills the gap in existing research. With
the help of the public resources (PubChem BioAssay and STRING), this
analysis strategy has the advantages of simplicity, convenience,
efficiency, rapidness, and low-cost. In the following sections, we
briefly discussed this strategy using the treatment of OA by HL as an
example.
Itga2b and Itgb3 are two subunits of integrin, both of which
heterodimerize to form a complex (Cordeiro et al., 2016). The expression
of both subunits may be influenced by each other. As shown in Figure 3,
eleven compound targets (CBFB, FYN, HDAC1, HSP90AA1, ITGA4, LCK, MAPK1,
PIK3CA, PTPN1, RUNX1, and SYK) are combined with both biolabels to form
a synergistic regulation network with Itga2b and Itgb3 as the core.
According to Reactome pathway database (https://reactome.org), CBFB,
RUNX1, and HDAC1 may regulate Itga2b gene transcription; LCK interacts
with SYK to bind to Itga2b and Itgb3; PTPN1 interacts with Itga2b and
Itgb3. PIK3CA, MAPK1, and both biolabels participate in platelet
activation pathway annotated by KEGG (https://www.kegg.jp/kegg/). PIK3CA
and MAPK1 may activate Itga2b and Itgb3 through a series of cascade
reactions. In platelet activation pathway of KEGG database, FYN
modulates the downstream signal to activate Itga2b as well. Through the
prediction of SRTING database, HSP90AA1 and ITGA4 are very likely to
bind to Itgb3 and regulate this subunit.
In Figure 3, each compound may only modulate the biolabels by acting on
two to four targets. Therefore, if some of the targets are mutated, it
may lead to the single compound’s efficacy drop, and even failure. HL is
a complex system composed of multi-compounds, five of which (myricetin,
fisetin, esculetin, 7-hydroxycoumarin-4-acetic acid, and caffeic acid)
may synergistically regulate the expression of both biolabels through
their interventions on eleven targets. Thus, compared with the
intervention mode of a single compound, the
multi-compounds and multi-targets synergistic mode of action of herbal
medicines is more capable of producing stable efficacy in the treatment
of diseases and may reduce the possibility of drug resistance.
The above analysis indicates that myricetin, fisetin, esculetin,
7-hydroxycoumarin-4-acetic acid, and caffeic acid may be the active
ingredients of HL treating OA. To verify the analysis results, we
examined the effects of these compounds on the joint swelling,
synovial pathological injury, and synovial platelet aggregation in the
OA rat model induced by MIA.
Previous studies have shown that all of these compounds, except for 7-
hydroxycoumarin-4-acetic acid, may play the protective roles in OA
cartilage (Huang et al., 2018; Pan et al., 2019; Yamada et al., 1999;
Zheng et al., 2017). Besides cartilage, the synovium in OA also suffers
significant damage, and accompanied by synovial platelet aggregation
(Alunno et al., 2014; Balbaloglu et al., 2014; Li et al., 2020).
Subsequently, the platelet was activated to trigger thrombus formation
in synovial microcirculation and participate in cartilage damage
(Balbaloglu et al., 2014). However, to our knowledge, no study has shown
that these compounds can protect OA synovium by regulating the platelet
aggregation. Therefore, this study also provides a new reference for
their mechanism of action in the treatment of OA. In the MIA-induced OA
rat model (Figure 4), the synovium displays obvious damage, including
irregular synoviocytes arrangement and synovial hyperplasia. Meanwhile,
the expression of Itga2b and Itgb3 in the damaged synovium was
significantly up-regulated (Figures 5 and 6), indicating a massive
aggregation of platelets at this site. This is consistent with the
previous studies (Alunno et al., 2014; Balbaloglu et al., 2014; Li et
al., 2020). The results of the current experiment show that these
compounds may reverse the overexpression of both biolabels induced by
MIA, which may protect OA synovium against the platelet aggregation
(Figures 5 and 6).
Joint swelling reflects the presence of synovitis (Berenbaum, 2013).
Histopathological analysis in Figure 4 also shows that a large number of
inflammatory cells infiltrated into the damaged synovium induced by MIA.
Previous studies have shown that these compounds have anti-inflammatory
effects (Chang and Chiang, 1995; Hou et al., 2018; Huang et al., 2018;
Tubaro et al., 1988; Zheng et al., 2017), which is conducive to the
recovery of joint swelling and the inflammatory damage in the synovium
(Figure 4). Additionally, platelet aggregation and activation are also
the markers of synovial inflammation in OA (Alunno et al., 2014). From
this view, their anti-inflammatory effects may also contribute to the
inhibition of platelet aggregation by these compounds in OA synovium.