Journal Pre-proof Systems pharmacology-based study of Tanreqing injection in airway mucus hypersecretion Wei Liu, Xiawei Zhang, Bing Mao, Hongli Jiang PII:
S0378-8741(19)33159-9
DOI:
https://doi.org/10.1016/j.jep.2019.112425
Reference:
JEP 112425
To appear in:
Journal of Ethnopharmacology
Received Date: 7 August 2019 Revised Date:
9 November 2019
Accepted Date: 22 November 2019
Please cite this article as: Liu, W., Zhang, X., Mao, B., Jiang, H., Systems pharmacology-based study of Tanreqing injection in airway mucus hypersecretion, Journal of Ethnopharmacology (2019), doi: https:// doi.org/10.1016/j.jep.2019.112425. This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. © 2019 Published by Elsevier B.V.
Systems pharmacology analyses SBG
UFP
STC
LJT
Rat experiment
FSV
Tanreqing injection
Compound screening Cholic acid
Baicalin
Rats model establishment
Wogonin
Control group
Model group
TRQ group
Pathology Target analyses
Sample collections
Sample analyses Immunohistochemistry
** 30 20
**
C-T, T-D networks
TNF-α expression (pg/mL)
40
40
0
ELISA **
**
30 20 10 0
qPCR
10
TNF-α mRNA expression (fold change)
TNF-α expression (pg/mL)
Functional and pathway analyses
5 4 3 2 1 0
**
*
1
Systems Pharmacology-Based Study of Tanreqing Injection in Airway Mucus
2
Hypersecretion
3
Wei Liua,b, MD; Xiawei Zhangc, MS; Bing Maoa, MD and Hongli Jianga, MD
4 5 6
a
7
Medicine, West China Hospital of Sichuan University, 37 Guoxuexiang Lane, Chengdu,
8
Sichuan 610041, P. R. China
Division of Respiratory Medicine, Department of Integrated Traditional and Western
b
9
Department of Pulmonary Diseases, State Key Laboratory of Biotherapy of China,
10
West China Hospital of Sichuan University, 1 Keyuansilu Road, Chengdu, Sichuan
11
610041, P. R. China
12
c
13
Medicine, West China School of Medicine, Sichuan University, 37 Guoxuexiang Lane,
14
Chengdu, Sichuan 610041, P. R. China
Division of Respiratory Medicine, Department of Integrated Traditional and Western
15 16
Correspondence to: Dr. Hongli Jiang, Division of Respiratory Medicine, Department of
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Integrated Traditional and Western Medicine, West China Hospital, Sichuan University,
18
37 Guoxue Lane, Chengdu, Sichuan 610041, P. R. China; Telephone number: 0086-
19
18980606651; Fax number: 0086-028-854202210.
20 21
E-mail
22
[email protected] (Xiawei Zhang),
[email protected] (Bing Mao),
23
[email protected] (Hongli Jiang).
24
address
for
authors:
[email protected]
(Wei
Liu),
25
Abstract
26
Ethnopharmacological relevance
27
Mucus hypersecretion (MH) is recognized as a key pathophysiological and clinical
28
feature of many airway inflammatory diseases. MUC5AC is a major component of
29
airway mucus. Tanreqing injection (TRQ) is a widely used herbal formula for the
30
treatment of respiratory inflammations for years in China. However, a holistic network
31
pharmacology approach to understanding its therapeutic mechanisms against MH has
32
not been pursued.
33 34
Aim of the study
35
This study aimed to explore the systems-level potential active compounds and
36
therapeutic mechanisms of TRQ in the treatment of MH.
37 38
Materials and methods
39
We established systems pharmacology-based strategies comprising compound
40
screenings, target predictions, and pathway identifications to speculate the potential
41
active compounds and therapeutic targets of TRQ. We also applied compound-target
42
and target-disease network analyses to evaluate the possible action mechanisms of
43
TRQ. Then, lipopolysaccharide (LPS)-induced Sprague-Dawley (SD) rat model was
44
constructed to assess the effect of TRQ in the treatment of MH and to validate the
45
possible molecular mechanisms as predicted in systems pharmacology approach.
46 47
Results
48
The comprehensive compound collection successfully generated 55 compound
49
candidates from TRQ. Among them, 11 compounds with high relevance to the potential
50
targets were defined as representative and potential active ingredients in TRQ formula.
51
Target identification revealed 172 potential targets, including pro-inflammatory
52
cytokines of tumor necrosis factor α (TNF-α), interleukin (IL)-6, and IL-8. Pathway
53
analyses uncovered the possible action of TRQ in the regulation of IL-17 signaling
54
pathway and its downstream protein MUC5AC. Then in vivo experiment indicated that
55
TRQ could significantly inhibit LPS stimulated MUC5AC over-production as well as
56
the expression of TNF-α, IL-6, IL-8, and IL-17A, in both protein and mRNA levels.
57 58
Conclusions
59
Based on the systems pharmacology method and in vivo experiment, our work provided
60
a general knowledge on the potential active compounds and possible therapeutic targets
61
of TRQ formula in its anti-MH process. This work might suggest directions for further
62
research on TRQ and provide more insight into better understanding the chemical and
63
pharmacological mechanisms of complex herbal prescriptions in a network perspective.
64
Keywords
65
Tanreqing injection; Systems pharmacology; Mucus hypersecretion; Signaling pathway;
66
Traditional Chinese Medicine
67 68
Abbreviations
69
MH: mucus hypersecretion; LPS, lipopolysaccharide; TNF-α, tumor necrosis factor α;
70
IL, interleukin; COPD, chronic obstructive pulmonary disease; TRQ, Tanreqing
71
injection; SBG, Scutellaria baicalensis Georgi; PFU, Pulvis Fellis Ursi; CST, Cornu
72
Saigae Tataricae; LJT, Lonicera japonica Thunb; FSV, Forsythia suspensa (Thunb.)
73
Vahl; CBM, China BioMedical Literature; CNKI, Chinese National Knowledge
74
Infrastructure; TCM, Traditional Chinese Medicine; TCMSP, Traditional Chinese
75
Medicines for Systems Pharmacology Database and Analysis Platform; BATMAN-
76
TCM, Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese
77
Medicine; SysDT, Systems Drug Targeting; RF, Random Forest; SVM, Support Vector
78
Machine; PPI, protein-protein interactions; HINT, High-quality INTeractomes; OMIM,
79
Online Mendelian Inheritance in Man; CTD, Comparative Toxicogenomics Database;
80
TTD, Therapeutic Target Database; MeSHs, Medical Subject Headings; C-T,
81
compound-target; pC-pT: potential compound-potential target; pC-dT, potential
82
compound-respiratory diseases related target; T - D, target-disease; GO, gene ontology;
83
KEGG, Kyoto Encyclopedia of Genes and Genomes; SD, Sprague-Dawley; SPF,
84
specific pathogen free; AB, Alcian blue; PAS, periodic acid-Schiff; IOD, integrated
85
optical density; PTGS2, prostaglandin G/H synthase 2; DPPIV, dipeptidyl peptidase IV
86 87
1. Introduction Airway mucus hypersecretion (MH) is recognized as a prominent
88
pathophysiological feature in the progress of many airway inflammatory diseases such
89
as chronic obstructive pulmonary disease (COPD) and asthma. MH might directly link
90
to declined lung functions, elevated frequency and duration of respiratory infections,
91
and increased morbidity and mortality in susceptible patients by obstructing airways and
92
impairing gas exchange (Jeffery, 2001). Currently, the conventional mucolytic strategies
93
have variable and limited efficacy in inhibiting airway mucus oversecretion (Rogers and
94
Barnes, 2006).
95
The major components of airway mucus secretion are mucins, a family of high
96
molecular weight glycoproteins that are predominantly produced by goblet cells in the
97
epithelium. In 19 mucins (namely MUC1, 2, 3A, 3B, 4, 5AC, 5B, 6 - 9, 11-13 and 16-
98
20) that have been currently recognized in human respiratory secretions, MUC5AC
99
appears to be most abundantly expressed, in bronchial epithelium and also submucosal
100
glands (Rogers and Barnes, 2006). Previous studies showed that MUC5AC-deficient
101
mice were protected from severity and abundance of mucus plugging compared with
102
wild-type mice following allergen challenge (Evans et al., 2015).
103
In the search for new therapeutics for MH, a lot of herbal remedies have been proved
104
to possess expectorant and mucolytic properties through inhibiting MUC5AC secretion,
105
and are commonly adopted for expectorant management (Kwon et al., 2009; Oliviero et
106
al., 2016). Among them, traditional Chinese medicine (TCM) as a promising candidate
107
has a confirmed therapeutic effect for MH via the down-regulation of MUC5AC in
108
many studies (Jiang et al., 2011; Li et al., 2013; Wei et al., 2013). Tanreqing injection
109
(TRQ) is a well-known TCM prescription and consists of a complex mixture of
110
chemical ingredients extracted from five TCM drugs: Scutellaria baicalensis Georgi
111
(SBG, Huangqin), Pulvis Fellis Ursi (PFU, Xiongdanfen), Cornu Saigae Tataricae
112
(CST, Shanyangjiao), Lonicera japonica Thunb (LJT, Jinyinhua), and Forsythia
113
suspensa (Thunb.) Vahl (FSV, Lianqiao). TRQ was prepared with the following steps:
114
obtain the extracting solution of SBG through water extraction, alcohol precipitation,
115
acid precipitation, ultra-filtration, and purification; extract total chololicacid from PFU
116
through saponification and purification; extract total amino acid from CST through
117
hydration, purification and ultra-filtration; obtain dry extract paste from JLT through
118
boiling, purification and drying; obtain dry extract paste from FSV via ultrafiltration
119
and low temperature vacuum drying; mix the above extractions and dissolve them in
120
water and then propylene glycol to make injection preparations (Patent No.
121
CN1947746B). With its positive activities against various infections being largely
122
confirmed in pharmacological studies, TRQ has been predominately used in patients
123
with inflammatory airway diseases in China (Li et al., 2010; Liu et al., 2016a; Zhong et
124
al., 2010). However, its effects on MUC5AC expression and MH are less investigated.
125
In the present study, firstly, we would explore the active compounds, potential
126
therapeutic targets as well as the compound-target-disease interactions of TRQ by using
127
a previously developed systems pharmacology strategy that integrated sufficient high-
128
dimensional biological data through compounds, targets, pathways and networks
129
analyses. Secondly, we would observe the effect of TRQ on the expression of
130
MUC5AC and some of the potential molecular targets as indicated in systems
131
pharmacology in lipopolysaccharide (LPS)-induced rat models. Our study may throw
132
light on the possible therapeutic mechanisms of TRQ in the treatment of airway MH
133
and provide the basis for further studies.
134
2. Methods and materials
135
2.1. Candidate compound screening
136
The compounds of five components in TRQ were collected by means of data
137
mining. We did systematical literature searching in electronic databases including China
138
BioMedical Literature (CBM), Chinese National Knowledge Infrastructure (CNKI),
139
Cqvip Database, Wanfang Database, MEDLINE (PubMed), EMBASE (Ovid) and
140
Google Scholar. We also did a wide-scale data retrieval from professional
141
pharmaceutical databases including Shanghai Institute of Organic Chemistry, Chinese
142
Academy of Sciences (http://www.organchem.csdb.cn/scdb/default.asp), Traditional
143
Chinese Medicines for Systems Pharmacology Database and Analysis Platform
144
(TCMSP) (http://tcmspw.com/tcmsp.php) (Ru et al., 2014), Bioinformatics Analysis
145
Tool for Molecular Mechanism of Traditional Chinese Medicine (BATMAN-TCM)
146
(http://bionet.ncpsb.org/batman-tcm/index.php/Home/Index/index) (Liu et al., 2016b),
147
NCBI PubChem database (https://pubchem.ncbi.nlm.nih.gov), and DrugBank database
148
(https://www.drugbank.ca).
149 150
2.2. Potential therapeutic targets analysis
151
Firstly, Systems Drug Targeting (SysDT) algorithm, a pharmacophore modeling
152
approach, was employed to predict the possible treatment targets based on the collected
153
candidate compounds (Yu et al., 2012). This model involves protein and ligand
154
encoding vectors. It takes Random Forest (RF) and Support Vector Machine (SVM) as
155
the major ensemble-based methods and incorporates the chemical, genomic and
156
pharmacological information into an integrated framework using DrugBank database.
157
RF score ≥ 0.8 and SVM score ≥ 0.7 were set as the thresholds to screen potential
158
targets (Li et al., 2015). Next, we used the Retrieve/ID mapping tool in UniProt
159
database (https://www.uniprot.org/uploadlists/) to standardize the target-related genes
160
and screened genes for Homo sapiens. Secondly, we did protein-protein interactions
161
(PPI) analysis for potential treatment targets using High-quality INTeractomes (HINT)
162
database (http://hint.yulab.org/) to explore proteins that interact with these targets.
163
Thirdly, we matched these targets with respiratory disease-related targets that provided
164
by Online Mendelian Inheritance in Man (OMIM) (https://omim.org/), a comprehensive
165
and authoritative compendium of human genes and genetic phenotypes, to further
166
narrow the scope of therapeutic targets.
167 168
2.3. Network construction and functional analysis
169
The treatable diseases related to the potential targets were collected through
170
DrugBank, Comparative Toxicogenomics Database (CTD) (http://ctdbase.org/),
171
Therapeutic Target Database (TTD) (http://bidd.nus.edu.sg/group/cjttd/) and PharmGkb
172
database (https://www.pharmgkb.org/). The information of obtained disease was
173
classified into different groups using Medical Subject Headings (MeSHs)
174
(https://www.ncbi.nlm.nih.gov/mesh/) in PubMed database.
175
All results obtained above were integrated to constitute the compound-target (C-T)
176
network and target-disease (T-D) network using Cytoscape 3.6.1 software (Shannon et
177
al., 2003). The topological properties of networks were evaluated by the plugin of
178
Cytoscape (Bindea et al., 2009). In graphical networks, the degree of a node was
179
defined as the number of edges connected with it, representing the importance of the
180
node in a network. We performed gene ontology (GO) and Kyoto Encyclopedia of
181
Genes and Genomes (KEGG) pathway enrichment to facilitate the biological
182
interpretations. We conducted the functional and pathway analysis for targets related to
183
TRQ using ClueGo assay (Bindea et al., 2009).
184 185 186
2.4. Animals and experimental groups Male Sprague-Dawley (SD) rats of 10-12 weeks old were obtained from Jianyang
187
Animal and Science Co., Ltd. (Jianyang, Sichuan, China). The animal experiment was
188
conducted following guidelines set forth by the Animal Care and Use Committee of
189
West China Hospital of Sichuan University. After 7 days of adaptive feeding in
190
polycarbonate boxes under specific pathogen-free (SPF) conditions, 30 SD rats were
191
randomly assigned to one of three experimental groups (n=10 per group): control group,
192
model group, and TRQ group. In the first day, 120 µL LPS (Escherichia coli 055: B5;
193
Sigma, USA, 2 mg/mL) (model group, and TRQ group) or saline (control group) was
194
intratracheally instilled. TRQ (Shanghai Kai Bao Pharmaceutical Co., LTD, China, 2.8
195
ml/kg) (TRQ group) or saline (control group and model group) was intraperitoneally
196
injected 1 h before intratracheal instillation. Rats were anesthetized with intraperitoneal
197
4 % sodium pentobarbital (40 mg/kg), and the right lungs were collected at 24 h as
198
prescribed before (Liu et al., 2016a).
199 200
2.5. Histopathological staining
201
Paraffin-embedded sections (4 µm) were stained with haematoxylin and eosin (HE)
202
for airway morphology evaluation and Alcian blue (AB)/periodic acid-Schiff (PAS) for
203
mucus secretion assessment. The evaluation of inflammation lesions was performed
204
using a previously reported numeric scale, which scored the
205
peribronchial/peribronchiolar, perivascular and alveolar inflammations from 0 to 10 in
206
total (Liu et al., 2016a). Percentage of AB/PAS positively stained area to the total area
207
of the bronchial epithelium was measured for MH evaluation (Tesfaigzi et al., 2004).
208 209 210
2.6. Ιmmunohistochemical staining Ιmmunohistochemical staining for MUC5AC was done using standard histological
211
methods as previously established (Liu et al., 2016a). Frozen lung specimens embedded
212
in paraffin were sectioned, deparaffinized, rehydrated and washed. Nonspecific binding
213
was blocked for 1 h with 1% BSA in PBS containing 0.05 % Tween 20. Specimens
214
were then incubated with antibodies against MUC5AC (Cat. Number: M00612;
215
dilution: 1:500, BosterBio, Pleasanton, CA, USA). A rabbit isotype control (Cat.
216
Number: ab199376, Abcam, Burlingame, CA, USA) was used to replace the primary
217
antibody as a negative control. The integrated optical density (IOD) was calculated by
218
measuring 10 consecutive visual fields for each sample at a magnification of 400 ×,
219
using an optical microscope equipped with an Image-Pro Plus software (version 6.0,
220
Media Cybernetics, Silver Spring, MD, USA). The quantification of histological
221
staining was carried out by a pathologist unaware of group identity.
222 223 224
2.7. ELISA analysis Quantitation of TNF-α, IL-6, CXCL-1/CINC-1 (rat analogue of human IL-8), IL-
225
17A and MUC5AC in lung homogenate was determined by ELISA technique,
226
according to the manufacturer’s instructions. Three replicates were carried out for each
227
of the different treatments. Rat TNF-α ELISA kit (Cat. Number: RTA00; Sensitivity: 5
228
pg/mL; Assay Range: 12.5-800 pg/mL), IL-6 ELISA kit (Cat. Number: R6000B;
229
Sensitivity: 0.7 pg/mL; Assay Range: 3.1-700 pg/mL) and CXCL-1/CINC-1 ELISA kit
230
(Cat. Number: RCN100; Sensitivity: 1.3 pg/mL; Assay Range: 7.8-500 pg/mL) were
231
purchased from R&D Systems (Minneapolis, MN, USA). Rat MUC5AC ELISA kit
232
(Cat. Number: MBS005394, Sensitivity: 1.0 ng/mL; Assay Range: 6.25-200 ng/mL)
233
was purchased from MyBioSource (San Diego, CA, USA). Rat IL-17A ELISA kit (Cat.
234
Number: ab214028, Sensitivity: 1.1 pg/ml; Assay Range: 6.25-400 pg/m) was
235
purchased from Abcam (Burlingame, CA, USA). The optical density of each well was
236
determined at 450 nm using a microplate reader (Bio-Rad, Richmond, CA, USA) within
237
30 min.
238 239 240
2.8. Real-time q-PCR analysis Quantitation of mRNA expression of TNF-α, IL-6, CXCL-1/CINC-1, IL-17A, and
241
MUC5AC in lung homogenate was determined by real-time q-PCR method. Total
242
RNAs from rat lung tissues were extracted using E.Z.N.ATM HP total RNA kit (Omega
243
Biotech, Norcross, GA, USA) and were reversely transcribed to prepare the first-strand
244
cDNA using iScript cDNA synthesis kit (Bio-Rad Laboratories, Hercules, CA, USA).
245
Primers used are: TNF-α forward primer (5’-TGCTATCTCATACCAGGAGA-3’) and
246
reverse primer (5’-GACTCCGCAAAGTCTAAGTA-3’); IL-6 forward primer (5’-
247
TCTTGGGACTGATGTTGTTG-3’) and reverse primer (5’-
248
TAAGCCTCCGACTTGTGAA-3’); CXCL-1/CINC-1 forward primer (5’-
249
CTCCAGCCACACTCCAACAGA-3’) and reverse primer (5’-
250
CACCCTAACACAAAACACGAT-3’); MUC5AC forward primer (5’-
251
CAATAACCACCCGGTCCAG-3’) and reverse primer (5’-
252
CAACTCCAGCAGAAGACTGT-3’); IL-17A forward primer (5’-
253
ATTCTGTTCTCATCCAGCAAG-3’) and reverse primer (5’-
254
AGGTCTCTGTTTAGGACGCA -3’); β-actin forward primer (5’-
255
CCTCATGAAGATCCTGACCG-3’) and reverse primer (5’-
256
ACCGCTCATTGCCGATAGTG-3’).
257 258 259
2.9. Statistical analysis Numerical data were shown as mean value ± standard deviation. The Kruskal-Wallis
260
H test was used for multiple comparisons between groups. A probability value of P <
261
0.05 were considered significant in all analyses. Statistical analyses were processed
262
using software package SPSS 23.0 (IBM SPSS Inc., Chicago, IL, USA).
263
264
3. Results
265
3.1. Compound determination
266
Comprehensive compound screening yielded a total of 55 compound candidates
267
from TRQ (Supplementary Table A). The number of compound candidates in LJT, SBG,
268
FSV, PFU and CST was 28, 18, 10, 13 and 9, respectively, with some compounds shared
269
by more than one herbal constitutes. By observing the candidate pool, the compounds
270
could be classified into several categories: phenylpropanoids, flavonoids, alkaloids, and
271
iridoids, according to their structures.
272
3.2. Target prediction
273
Based on the target fishing approach, 172 potential targets were read out and
274
validated from 41 potential compounds, with 14 compounds hitting no targets (Figure 1
275
and Supplementary Table B). A distinct target overlap between the 5 TCM drug
276
constituents was found. These potential targets were mainly receptors and enzymes, and
277
were widely distributed in multiple systems involving the respiratory tract, circulation
278
system, brain, liver, and kidney. The potential compounds in TRQ targeted many
279
proteins that played pivotal roles in physiological and pathological processes of
280
respiratory inflammatory diseases, including prostaglandin G/H synthase 2 (PTGS2),
281
dipeptidyl peptidase IV (DPPIV), and some pro-inflammatory cytokines such as TNF-α,
282
IL-6, and IL-8.
283
3.3. C-T network
284
In order to identify the interaction between the filtered 41 potential compounds (pC)
285
and 172 potential targets (pT), a pC-pT network was established (Figure 1). According
286
to Figure 1, the degree value of the compounds that reflected centrality of the network
287
varied significantly from 1 to 45, with an average value of 9.2 (Supplementary Table B).
288
Eleven compounds possessed a degree value higher than 10, which indicated that they
289
might be crucial for the therapeutic effect of TRQ. Among them, 4 highly degreed
290
molecules, wogonin (degree=45), baicalein (degree=37), chrysin 7-O-glucuronide
291
(degree=21), and phenylalanine (degree=21), were identified as the major chemical
292
components from Scutellaria baicalensis Georgi (Liau et al., 2019; Liu et al., 2014).
293
Two other representative compounds, chenodeoxycholic acid (degree=33) and
294
ursodeoxycholic acid (degree=21), were critical endogenous bile acids extracted from
295
Pulvis Fellis Ursi. Amino acids including glutamic acid (degree=27), phenylalanine
296
(degree=21), tyrosine (degree=20), valine (degree=20), and isoleucine (degree=11) were
297
identified as the main chemical compositions in Cornu Saigae Tataricae.
298 299 300
Figure 1. pC-pT network (where green nodes represent compounds and blue nodes represent targets, while the lines represent the interactions between them).
301 302 303
After the PPI analysis, we matched potential targets to specific diseases, and finally chose 75 respiratory diseases-related targets (dT) to do further in-depth research. A
304
potential compound - respiratory disease-related target (pC-dT) network composed of
305
116 nodes along with 236 edges was constructed (Figure 2). In this net, it was visually
306
notable that most of the potential compounds hit multiple targets, verifying the
307
“multiple compounds, network targets” feature of TRQ.
308
309 310 311
Figure 2. pC-dT network (where green nodes represent compounds and blue nodes
312
represent targets, while the lines represent the interactions between them).
313 314
3.4. GO and KEGG pathway analyses
315
The GO and KEGG pathway analyses were performed for understanding the
316
concerned biological processes, molecular functions and target-related pathways. As
317
shown in Figure 3, the biological processes of potential targets were mostly related to
318
the response to oxygen-containing compound (21.43 %), intracellular signal
319
transduction (21.43 %) and adrenergic receptor signaling pathway (14.29 %) (Figure 3
320
A). The molecular functions of potential targets mainly involved actions such as
321
carboxylic acid binding (28.12 %), zinc ion binding (21.88 %), catecholamine binding
322
(12.5 %) and transition metal ion binding (9.38 %) (Figure 3 B). The reactome of
323
potential targets were mainly related to the activation of IL-17 signaling pathway (56.04
324
%), arginine biosynthesis (16.48 %) and neuroactive ligand-receptor interaction (12.09
325
%) (Figure 3 C).
326 327
Figure 3. GO and KEGG pathway analyses concerned biological processes (A),
328
molecular functions (B) and target-related pathways (C).
329 330
3.5. T-D network
331
A T-D network was constructed based on potential targets and their related diseases
332
(Supplementary Table C). Two hundred diseases were classified into 21 groups
333
according to the MeSH Browser. As was shown in Figure 4, collected diseases were
334
mainly neoplasms (50/200), cardiovascular diseases (35/200), nervous system diseases
335
(26/200), mental disorders (13/200) and respiratory tract diseases (9/200).
336 337
Figure 4. T-D network (where blue nodes represent targets, yellow nodes represent
338
disease classification and purple nodes represent diseases, while the lines represent the
339
interactions between them).
340 341 342
3.6. Effects of TRQ on airway morphological changes Compared with control group (Figure 5 A), lung tissues of rats in model group
343
showed acute bronchopneumonia involving prominent thickening of the airway
344
epitheliums and conspicuous peribronchovascular inflammatory cell infiltration after
345
LPS instillation (Figure 5 B). TRQ treatment decreased the inflammatory lesion scores
346
by 29.8% (P < 0.05) (Figure 5 C, D).
347
A
C
B
348
Lung inflammation score
D 15
**
*
10
5
0
349 350
Figure 5: H&E staining of rat lung tissues in A) control group, B) model group and C)
351
TRQ group. Scale bars = 50 µm. D) Lung inflammation scores for histopathological
352
damage.
control group;
model group;
TRQ group. * P < 0.05, ** P < 0.01.
353 354 355
3.7. Effect of TRQ on airway goblet cell hyperplasia and mucus production Compared with control group (Figure 6 A), noticeable mucus overproduction and
356
goblet cell hyperplasia were observed along the airway surface epithelium in LPS-
357
treated mice, with a significant positive AB/PAS staining being detected (Figure 6 B,
358
D). TRQ treatment for 24 hours contributed to a significant relief in both mucous
359
hypersecretion and mucus cell hyperplasia by 30.5% (P < 0.01) (Figure 6 C, D).
360
A
C
B
361
AB/PAS positive staining area (%)
D 20
**
**
15 10 5 0
362 363
Figure 6: AB/PAS staining of rat lung tissues in A) control group, B) model group and
364
C) TRQ group. Scale bars = 50 µm; upper right insert scale bars = 25 µm. D) The
365
percentage of AB/PAS positively staining area to total epithelial area in rat airways.
366
control group;
model group;
TRQ group. * P < 0.05, ** P < 0.01.
367 368 369
3.8. Effect of TRQ on MUC5AC expression in lung tissues Compared with control group (Figure 7 A), MUC5AC positively stained granules in
370
rat lungs were significantly increased 24 hours after LPS challenge in model group
371
(Figure 7 B, D). TRQ injection significantly attenuated LPS-induced MUC5AC
372
expression in lung tissues by 68.5% (P < 0.01) (Figure 7 C, D).
A
C
B
373 D
374 375
Figure 7: MUC5AC immunohistochemical staining of rat lung tissues in A) control
376
group, B) model group and C) TRQ group. Scale bars 50 µm. D) IOD value of positive
377 378
MUC5AC staining in rat lung tissues.
control group;
model group;
TRQ
group. ** P < 0.01.
379 380 381
3.9. Effect of TRQ on MUC5AC expression in lung homogenate Compared with control group, a noticeable increase in the protein and mRNA
382
expression of MUC5AC was observed 24 hours after LPS administration. Pre-treatment
383
with TRQ helped to decrease the level of MUC5AC in both protein and gene levels by
384
25.1% and 17.4%, respectively (P < 0.05) (Figure 8).
385
0.6 0.4 0.2 0.0
**
*
MUC5AC mRNA expression (fold change)
MUC5AC expression (ng/m L)
0.8
40
**
*
30 20 10 0
386 387
Figure 8: Protein and mRNA levels of MUC5AC.
control group;
model group;
TRQ group. * P < 0.05, ** P < 0.01.
388 389 390
3.10. Effect of TRQ on TNF-α, IL-6, and CXCL-1/CINC-1 expressions in lung
391
homogenate
392
Compared with control group, LPS treatment induced significant elevation in the
393
protein and gene levels of TNF-α, IL-6, and CXCL-1/CINC-1 at 24 h. Intraperitoneal
394
injection of TRQ effectively inhibited the protein expression of TNF-α, IL-6, and
395
CXCL-1/CINC-1 by 26.9%, 35.6%, and 35.1%, respectively (P < 0.01), and the mRNA
396
expression by15.4%, 18.9%, and 15.4%, respectively ((P < 0.05). (Figure 9).
397 398
**
20 10 0
**
**
100
50
400 401
**
*
**
*
**
*
4 3 2 1 0
3 2 1 0
**
**
100
50
0
5 4
(fold change)
150
CXCL-1/CINC-1 mRNA expression
CXCL-1/CINC-1 expression (pg/mL)
0
399
5
4
IL-6 mRNA expression (fold change)
150
IL-6 expression (pg/mL)
**
30
TNF-α mRNA expression (fold change)
TNF-α expression (pg/mL)
40
3 2 1 0
Figure 9: Protein and mRNA levels of TNF-α, IL-6, and CXCL-1/CINC-1. group;
model group;
control
TRQ group. * P < 0.05, ** P < 0.01
402 403 404
3.11. Effect of TRQ on IL-17A expressions in lung homogenate Compared with control group, protein and mRNA levels of IL-17A distinctively
405
increased in model group. TRQ treatment effectively reduced LPS-stimulated IL-17A
406
expression in both protein and mRNA levels by 72.0% and 69.2%, respectively (P <
407
0.05) (Figure 10).
408
410 411 412
150 100 50
**
*
IL-17A mRNA expression (fold change)
IL-17A expression (pg/mL)
409
200
0
Figure 10: Protein and mRNA Levels of IL-17A.
*
4
*
3 2 1 0
control group;
TRQ group. (* P < 0.05, ** P < 0.01)
model group;
413 414
4. Discussion As TCM pipeline has grown in recent years, systems pharmacology as an effective
415
way to expedite the pharmacological discovery of TCM has gained considerable ground
416
over the past decades. Systems pharmacology is considered to be a well-characterized
417
approach to highlight the manner in which the active compounds and
418
polypharmacological therapeutic mechanisms of multi-compound TCM drugs could be
419
reliably identified. In this study, we conducted systems pharmacology and rat
420
experiment to accumulate the “systems-level” information of TRQ. The results of this
421
work were expected to facilitate the pharmacological discovery of TRQ and laid a
422
foundation for further studies.
423
According to the degree of nodes in C-T network system, we identified 11 chemical
424
constituents as the potential active compounds which might take part in the
425
administrative processes of TRQ in the treatment of MH. Specifically, the top two
426
degreed compounds, baicalein and wogonin, have well established roles in airway
427
inflammation (Dinda et al., 2017; Kim et al., 2018; Ku and Bae, 2015; Luo et al., 2016;
428
Qi et al., 2013; Qinghe et al., 2019) and mucous hypersecretion (Lee et al., 2010; Lucas
429
et al., 2015).
430
We linked the potential compounds with their corresponding targets through C-T
431
network construction. Based on the approaches combined with chemometric method,
432
information integration, and data-mining, we demonstrated that PTGS2, DPPIV, as well
433
as pro-inflammatory cytokines including TNF-α, IL-6, and IL-8 might be the potential
434
targets hit by TRQ compound candidates. As the combinatorial art of TCM formula
435
may shift “one drug, one target” paradigm to “multiple component, network target”
436
strategy (Fitzgerald et al., 2006), we consider that the “network target” system can work
437
in two different ways in the condition of MH. On one hand, these targets individually
438
act as inhibitors in mucus overproduction. For example, DPPIV is a serine exopeptidase
439
that could inactivate various pro-inflammatory molecules (such as neuropeptides,
440
chemokines, and cytokines) by selectively removing the N-terminal dipeptides from
441
their biological structures (Landis et al., 2008). It could be helpful in MH by
442
inactivating the functional ability of Substance P, a peptide that could stimulate
443
submucosal gland secretion and exacerbate inflammatory conditions (Grouzmann et al.,
444
2002). On the other hand, protein-protein interactions might happen in the network and
445
contribute to the therapeutic process. In the last decades, TNF-α, IL-6, and IL-8 were
446
primarily proved to be potent inducers of airway mucus overproduction by upregulating
447
MUC5AC expression in airway epithelial cells (Chakir et al., 2003; Chen et al., 2003;
448
Hashimoto et al., 2004; Wang et al., 2007), which indicated the association between
449
airway inflammation and mucus production. PTGS2 is a pivotal synthase involved in
450
the conversion of various prostaglandins. It is not typically present under normal
451
conditions in most cells but rapidly induced by inflammatory cytokines associated with
452
inflammations. Studies have shown that PTGS2 is implicated in TNF-α stimulated
453
MUC5AC expression (Ricciotti and FitzGerald, 2011)(Li and Zhou, 2008).
454
We constructed multilevel networks (molecular-target-disease) to explore the
455
correlations between the potential compounds of TRQ and diseases from a systematic
456
perspective. It is currently understood that airway inflammation is a complex disorder
457
associated with multiple alterations in molecular pathways and complex interactions at
458
the cellular and organ levels (Loscalzo et al., 2007). Compared with the treatment with a
459
single, “magic bullet” therapy, TRQ regimen with a nature of “multiple component,
460
network target” may exert a therapeutic benefit on MH through comprehensive effects
461
on tumorigenesis, cardiovascular system, immune system, nutritional and metabolic
462
conditions and nervous system.
463
The pathway analysis showed that most targets of potential compounds in TRQ
464
were associated with IL-17 signaling pathway, which indicated that IL-17 might be
465
involved in the molecular mechanisms of TRQ. IL-17 (IL-17A) is a signature cytokine
466
secreted by activated CD4+ Th17 cells, γδ T cells, natural killer T cells, and innate
467
lymphoid cells. Studies proved that IL-17 stimulation resulted in a consistent and strong
468
upregulation on MUC5AC expression in both human and animal models (Chakir et al.,
469
2003; Chen et al., 2003). The results of KEGG analyses in our study also demonstrated
470
that MUC5AC was a pivotal downstream protein in IL-17 signaling pathway cascade.
471
Besides, previous studies showed that IL-17 could induce a dramatic increase in the
472
expression of IL-6, IL-8 and TNF-α from bronchial epithelial cells (Kawaguchi et al.,
473
2001) and macrophages (Jovanovic et al., 1998). Moreover, IL-17 played a synergistic
474
augmenting effect on TNF-α stimulated IL-8 and IL-6 secretion in human airways
475
(Henness et al., 2004; Honda et al., 2016). Therefore, IL-17 suppression might play a
476
role in the treatment of MH through a direct way by inhibiting the downstream
477
MUC5AC production and an indirect way by downregulating the proinflammatory
478
cytokines.
479
5. Conclusion
480
To conclude, TRQ contains various ingredients with different pharmacologic
481
properties that act on multiple targets; TRQ plays a therapeutic effect against mucus
482
hypersecretion and MUC5AC production, likely at least partially, through the inhibition
483
of IL-6, IL-8 and TNF-α and IL-17. Further studies on the molecular basis are needed to
484
verify the results of the current work and to discover more about therapeutic
485
mechanisms of TRQ. Systems pharmacology as a novel analytical method can be
486
rational and reliable in processing the compound discovery and understanding the
487
scientific connotation of TCM from a biological perspective.
488 489
Conflicts of interest The authors declare that they have no conflicts of interest.
490
491
Acknowledgements
492
This work was supported by the National Natural Science Foundation of China
493
(grant number 81700024), the China Postdoctoral Science Foundation Grant (grant
494
number 2018M643505), and the Post-Doctor Research Project, West China Hospital,
495
Sichuan University (grant number 2018HXBH039).
496 497 498
Author contributions Wei Liu and Xiawei Zhang contributed equally to this work; Wei Liu, Bing Mao
499
and Hongli Jiang conceived and designed the experiments; Wei Liu and Xiawei Zhang
500
conducted the experimental work and analysis; Wei Liu drafted the manuscript; Hongli
501
Jiang provided major revisions and comments to the manuscript. All authors reviewed
502
and approved the final manuscript.
503 504 505 506
507
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