Pentagalloyl glucose increases elastin deposition, decreases reactive oxygen species and matrix metalloproteinase activity in pulmonary fibroblasts under inflammatory conditions

Directed Assembly of Elastic Fibers via Coacervate Droplet Deposition on Electrospun Templates

Elastic fibers provide critical elasticity to the arteries, lungs, and other organs. Elastic fiber assembly is a process where soluble tropoelastin is coacervated into liquid droplets, cross-linked, and deposited onto and into microfibrils. While much progress has been made in understanding the biology of this process, questions remain regarding the timing of interactions during assembly. Furthermore, it is unclear to what extent fibrous templates are needed to guide coacervate droplets into the correct architecture. The organization and shaping of coacervate droplets onto a fiber template have never been previously modeled or employed as a strategy for shaping elastin fiber materials. Using an in vitro system consisting of elastin-like polypeptides (ELPs), genipin cross-linker, electrospun polylactic-co-glycolic acid (PLGA) fibers, and tannic acid surface coatings for fibers, we explored ELP coacervation, cross-linking, and deposition onto fiber templates. We demonstrate that integration of coacervate droplets into a fibrous template is primarily influenced by two factors: (1) the balance of coacervation and cross-linking and (2) the surface energy of the fiber templates. The success of this integration affects the mechanical properties of the final fiber network. Our resulting membrane materials exhibit highly tunable morphologies and a range of elastic moduli (0.8-1.6 MPa) comparable to native elastic fibers.

Binding of Pentagalloyl Glucose to Aortic Wall Proteins: Insights from Peptide Mapping and Simulated Docking Studies

Pentagalloyl glucose (PGG) is currently being investigated as a non-surgical treatment for abdominal aortic aneurysms (AAAs); however, the molecular mechanisms of action of PGG on the AAA matrix components and the intra-luminal thrombus (ILT) still need to be better understood. To assess these interactions, we utilized peptide fingerprinting and molecular docking simulations to predict the binding of PGG to vascular proteins in normal and aneurysmal aorta, including matrix metalloproteinases (MMPs), cytokines, and fibrin. We performed PGG diffusion studies in pure fibrin gels and human ILT samples. PGG was predicted to bind with high affinity to most vascular proteins, the active sites of MMPs, and several cytokines known to be present in AAAs. Finally, despite potential binding to fibrin, PGG was shown to diffuse readily through thrombus at physiologic pressures. In conclusion, PGG can bind to all the normal and aneurysmal aorta protein components with high affinity, potentially protecting the tissue from degradation and exerting anti-inflammatory activities. Diffusion studies showed that thrombus presence in AAAs is not a barrier to endovascular treatment. Together, these results provide a deeper understanding of the clinical potential of PGG as a non-surgical treatment of AAAs.

Elastin-targeted nanoparticles delivering doxycycline mitigate cytokine storm and reduce immune cell infiltration in LPS-mediated lung inflammation

BACKGROUND AND PURPOSE

Cytokine storm invoked during acute and chronic lung injury promotes alveolar damage and remodeling. The current study shows that degraded elastin-targeted nanoparticles releasing doxycycline (Doxy NPs) are potent in mitigating cytokines storm, migration of immune cells in the lungs, and inhibiting inflammasome pathways in the LPS mouse model.

EXPERIMENTAL APPROACH

Cytokine storm and lung injury were induced using LPS and elastase in C57BL/6 mice (rodent model for emphysema). The mice were then treated with I.V. Doxy NPs, blank NPs, or Doxy a day before LPS administration. Cytokine levels, immune cell population, and MMP activity were analyzed in broncheo-alveolar lavage fluid (BALF) 4 hours after LPS administration. Additionally, gene expression of IL-6, IL-1beta, MCP-1, NLRP3, Caspase 1 and MMPs were investigated in alveolar cells on day 3 after LPS administration.

KEY RESULTS

Doxycycline NPs but not Doxycycline significantly decreased IL-6, TNF-α, IL-23 and were significantly more effective in decreasing the percentage of immune cells in the BALF. This is the first in-vivo study to demonstrate that Doxycycline can effectively inhibit inflammasome pathways in the lungs.

CONCLUSION AND IMPLICATIONS

IV administration of elastin antibody conjugated Doxycycline-loaded albumin NPs can effectively modulate the local immune environment in the lungs, which is not achieved by IV Doxycycline even at 100-fold higher dose. This novel method of drug delivery can effectively lead to the repurposing of traditional Doxycycline as a potential adjunct treatment for managing the cytokine storm in the lungs in COPD and viral infections.

Role of elastic fiber degradation in disease pathogenesis

Elastin is a crucial extracellular matrix protein that provides structural integrity to tissues. Crosslinked elastin and associated microfibrils, named elastic fiber, contribute to biomechanics by providing the elasticity required for proper function. During aging and disease, elastic fiber can be progressively degraded and since there is little elastin synthesis in adults, degraded elastic fiber is not regenerated. There is substantial evidence linking loss or damage of elastic fibers to the clinical manifestation and pathogenesis of a variety of diseases. Disruption of elastic fiber networks by hereditary mutations, aging, or pathogenic stimuli results in systemic ailments associated with the production of elastin degradation products, inflammatory responses, and abnormal physiology. Due to its longevity, unique mechanical properties, and widespread distribution in the body, elastic fiber plays a central role in homeostasis of various physiological systems. While pathogenesis related to elastic fiber degradation has been more thoroughly studied in elastic fiber rich tissues such as the vasculature and the lungs, even tissues containing relatively small quantities of elastic fibers such as the eyes or joints may be severely impacted by elastin degradation. Elastic fiber degradation is a common observation in certain hereditary, age, and specific risk factor exposure induced diseases representing a converging point of pathological clinical phenotypes which may also help explain the appearance of co-morbidities. In this review, we will first cover the role of elastic fiber degradation in the manifestation of hereditary diseases then individually explore the structural role and degradation effects of elastic fibers in various tissues and organ systems. Overall, stabilizing elastic fiber structures and repairing lost elastin may be effective strategies to reverse the effects of these diseases.

The most bioactive fraction of stir-fried Radix Paeoniae Alba regulating IL-6/STAT3 signaling pathway in allergic asthma mouse

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Paeoniae Alba (RPA), a traditional Chinese medicine, has been used frequently in the treatment of asthma. Previous studies demonstrated the dichloromethane fraction of Stir-Frying RPA (FDCM) enhanced the effect of anti-allergic asthma compared with the dichloromethane fraction of RPA (DCM).

AIM OF THE STUDY

The significant increasing of Paeoniflorin (PF), ethyl gallate (EG), 1,2,3,4,6-pentagalloylglucose (PGG) had been observed in FDCM. This study aimed to investigate the effects and mechanisms of these compounds from FDCM in ovalbumin (OVA)-induced allergic asthma mouse model.

MATERIALS AND METHODS

The significant difference contents compounds fraction (FB-40) and other fractions in FDCM were enriched by Medium Pressure Liquid Chromatography (MPLC). The pharmacodynamics was verified among all fractions in OVA-induced allergic asthma mice. Moreover, the drug dose dependence of FB-40 (0.42 mg/kg, 0.21 mg/kg, and 0.07 mg/kg), which were the most active fraction from FDCM for anti-allergic asthma, was explored. The expression of IL-6, p-STAT3, and STAT3 was analyzed by Western blot analysis. In addition, the main components of FB-40 were identified by UPLC with standards. Finally, the anti-inflammatory effects of the main components from FB-40 were detected by LPS-stimulated BEAS-2B cells using an Elisa assay.

RESULTS

The results showed that FB-40 was the most active fraction from FDCM, which could significantly improve the lung tissue pathological condition, and decrease the number of inflammatory cells in bronchoalveolar lavage fluid (BALF). It had greater pharmacological activity than its main component PF. FB-40 also showed dose dependence and regulated the IL-6/STAT3 signaling pathway in allergic asthma mice. Besides, PF, Albiflorin (AF), PGG, EG, and 1,2,3,6-Tetra-O-galloyl-β-D-glucose (TGG) from FB-40 were identified by UPLC with the standard. At last, in the LPS-induced BEAS-2B cell experiments, EG, PGG, 1,2,3,6-Tetra-O-galloyl-β-D-glucose (TGG) showed stronger inhibiting activities of cytokine than the monoterpenoid glycosides (PF and AF).

CONCLUSION

The research proved that FB-40 was an active fraction in FDCM, which regulates IL-6/STAT3 Signaling Pathway to ameliorate allergic asthma. Gallic acids including TGG and PGG, and EG also play a role in the treatment of allergic asthma in FB-40.

Reversal of elastase-induced abdominal aortic aneurysm following the delivery of nanoparticle-based pentagalloyl glucose (PGG) is associated with reduced inflammatory and immune markers

OBJECTIVE

An Abdominal aortic aneurysm (AAA), a deadly disease in elderly population, is featured by expansion of aortic diameter, degradation and weakening of vasculature. Its common and significant characteristics are disarray and inflammation in vasculature. We tested the hypothesis that the reversal of abdominal aortic aneurysm by pentagalloyl glucose-loaded nanoparticles (PGG-NPs) therapy that targets degraded elastin suppresses inflammatory and immune markers to ameliorate the pathophysiology of the disease in advance stage aneurysm in a porcine pancreatic elastase (PPE)-induced mouse model of AAA.

METHODS AND RESULTS

After induction of aneurysm in pathogen-free C57BL/6 male mice by applying PPE peri-adventitially to the abdominal aorta, once a week for two doses of intravenous injections of pentagalloyl glucose-loaded nanoparticles (PGG-NPs) conjugated with elastin targeted antibody were used to reverse the aneurysms. We showed that PGG-NPs therapy could suppress infiltration of macrophages, CD8 and CD4 subsets of T cells, matrix metalloproteinases (MMPs), inflammatory cytokines interferon (IFN-γ) and interleukin (IL)-6 at the local and systemic level. Moreover, such PGG-NPs therapy increases the induction of anti-inflammatory cytokines IL-13, IL-27 and IL-10 at the local and systemic level. The therapy also led to remodeling of elastic lamina at the aneurysm site.

CONCLUSION

Nanoparticles-loaded pentagalloyl glucose therapy can be an effective treatment option against advanced stage aneurysms to reverse the disease by ameliorating inflammation and restoring arterial homeostasis.

Targeted delivery of pentagalloyl glucose inhibits matrix metalloproteinase activity and preserves elastin in emphysematous lungs

Background

Elastin degradation has been established as one of the driving factors of emphysema. Elastin-derived peptides (EDPs) are shown to act as a chemoattractant for monocytes. Effectively shielding elastin from elastolytic damage and regenerating lost elastin are two important steps in improving the mechanical function of damaged lungs. Pentagalloyl glucose (PGG) has been shown to preserve elastin in vascular tissues from elastolytic damage in vivo and aid in elastin deposition in vitro.

Methods

We created emphysema by elastase inhalation challenge in mice. Albumin nanoparticles loaded with PGG, conjugated with elastin antibody, were delivered to target degraded elastin in lungs. We investigated matrix metalloproteinase-12 activity and lung damage by measuring dynamic compliance and tidal volume changes.

Results

Ex-vivo experiments demonstrated elastin preservation in PGG treated samples compared to controls. Inhaled nanoparticles conjugated with elastin antibody retained for extended periods in lungs. Further, mice treated with PGG nanoparticles showed a significant suppression of MMP-12 activity measured in the lungs. We observed suppression of emphysema in terms of dynamic lung compliance and tidal volume change compared to the control group. The histological examination further confirmed elastin preservation in the lungs.

Conclusion

These results demonstrate successful targeted delivery of nanoparticles loaded with PGG to inhibit MMP-12 activity and preserve elastin in the lungs. Such targeted PGG therapy has potential therapeutic use in the management of emphysema.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01838-1.

Effect of all-trans retinoic acid and pentagalloyl glucose on smooth muscle cell elastogenesis

BACKGROUND

The main objective of tissue engineering is to fabricate a tissue construct that mimics native tissue both biologically and mechanically. A recurring problem for tissue-engineered blood vessels (TEBV) is deficient elastogenesis from seeded smooth muscle cells. Elastin is an integral mechanical component in blood vessels, allowing elastic deformation and retraction in response to the shear and pulsatile forces of the cardiac system.

OBJECTIVE

The goal of this research is to assess the effect of the vitamin A derivative all-trans retinoic acid (RA) and polyphenol pentagalloyl glucose (PGG) on the expression of elastin in human aortic smooth muscle cells (hASMC).

METHODS

A polycaprolactone (PCL) and the gelatin polymer composite was electrospun and doped with RA and PGG. The scaffolds were subsequently seeded with hASMCs and incubated for five weeks. The resulting tissue-engineered constructs were evaluated using qPCR and Fastin assay for their elastin expression and deposition.

RESULTS

All treatments showed an increased elastin expression compared to the control, with PGG treatments showing a significant increase in gene expression and elastin deposition.

Pentagalloyl Glucose-Laden Poly(lactide-co-glycolide) Nanoparticles for the Biomechanical Extracellular Matrix Stabilization of an In Vitro Abdominal Aortic Aneurysm Model

The suppression of abdominal aortic aneurysm (AAA) growth by nonsurgical therapy is currently not an option, and AAA is considered an irreversible destructive disease. The formation and development of AAA is associated with the progressive deterioration of the aortic wall. Infiltrated macrophages and resident vascular smooth muscle cells oversecrete matrix metalloproteinases (MMPs), which cause the loss of crucial aortic extracellular matrix (ECM) components, thus weakening the aortic wall. Stabilization of the aortic ECM could enable the development of novel therapeutic options for preventing and reducing AAA progression. In the present work, we studied the biochemical and biomechanical interactions of pentagalloyl glucose (PGG) on mouse C2C12 myoblast cells. PGG is a naturally occurring ECM-stabilizing polyphenolic compound that has been studied in various applications, including vascular health, with promising results. With its known limitations of systemic administration, we also studied the administration of PGG when encapsulated within poly(lactide-co-glycolide) (PLGA) nanoparticles (NPs). Treatment with collagenase and elastase enzymes was used to mimic a pathway of degenerative effects seen in the pathogenesis of human AAA. PGG and PLGA(PGG) NPs were added to enzyme-treated cells in either a suppressive or preventative scenario. Biomolecular interactions were analyzed through cell viability, cell adhesion, reactive oxygen species (ROS) production, and MMP-2 and MMP-9 secretion. Biomechanical properties were studied through atomic force microscopy and quartz crystal microbalance with dissipation. Our results suggest that PGG or PLGA(PGG) NPs caused minor to no cytotoxic effects on the C2C12 cells. Both PGG and PLGA(PGG) NPs showed reduction in ROS and MMP-2 secretion if administered after enzymatic ECM degradation. A quantitative comparison of Young's moduli showed a significant recovery in the elastic properties of the cells treated with PGG or PLGA(PGG) NPs after enzymatic ECM degradation. This work provides preliminary support for the use of a pharmacological therapy for AAA treatment.

Systemic delivery of targeted nanotherapeutic reverses angiotensin II-induced abdominal aortic aneurysms in mice

Abdominal aortic aneurysm (AAA) disease causes dilation of the aorta, leading to aortic rupture and death if not treated early. It is the 14th leading cause of death in the U.S. and 10th leading cause of death in men over age 55, affecting thousands of patients. Despite the prevalence of AAA, no safe and efficient pharmacotherapies exist for patients. The deterioration of the elastic lamina in the aneurysmal wall is a consistent feature of AAAs, making it an ideal target for delivering drugs to the AAA site. In this research, we conjugated nanoparticles with an elastin antibody that only targets degraded elastin while sparing healthy elastin. After induction of aneurysm by 4-week infusion of angiotensin II (Ang II), two biweekly intravenous injections of pentagalloyl glucose (PGG)-loaded nanoparticles conjugated with elastin antibody delivered the drug to the aneurysm site. We show that targeted delivery of PGG could reverse the aortic dilation, ameliorate the inflammation, restore the elastic lamina, and improve the mechanical properties of the aorta at the AAA site. Therefore, simple iv therapy of PGG loaded nanoparticles can be an effective treatment option for early to middle stage aneurysms to reverse disease progression and return the aorta to normal homeostasis.

Therapeutic potential of plant-derived tannins in non-malignant respiratory diseases

Respiratory diseases are the major cause of human illness and death around the world. Despite advances in detection and treatment, very few classes of safe and effective therapy have been introduced to date. At present, phytochemicals are getting more attention because of their diverse beneficial activities and minimal toxicity. Tannins are polyphenolic secondary metabolites with high molecular weights, which are naturally present in a wide variety of fruits, vegetables, cereals, and leguminous seeds. Many tannins are endowed with well-recognized protective properties, such as anti-cancer, anti-microbial, anti-oxidant, anti-hyperglycemic, and many others. This review summarizes a large body of experimental evidence implicating that tannins are helpful in tackling a wide range of non-malignant respiratory diseases including acute lung injury (ALI), pulmonary fibrosis, asthma, pulmonary hypertension, and chronic obstructive pulmonary disease (COPD). Mechanistic pathways by which various classes of tannins execute their beneficial effects are discussed. In addition, clinical trials and our perspective on future research with tannins are also reviewed.

Nanoparticle-based targeted delivery of pentagalloyl glucose reverses elastase-induced abdominal aortic aneurysm and restores aorta to the healthy state in mice

AIM

Abdominal aortic aneurysms (AAA) is a life-threatening weakening and expansion of the abdominal aorta due to inflammatory cell infiltration and gradual degeneration of extracellular matrix (ECM). There are no pharmacological therapies to treat AAA. We tested the hypothesis that nanoparticle (NP) therapy that targets degraded elastin and delivers anti-inflammatory, anti-oxidative, and ECM stabilizing agent, pentagalloyl glucose (PGG) will reverse advance stage aneurysm in an elastase-induced mouse model of AAA.

METHOD AND RESULTS

Porcine pancreatic elastase (PPE) was applied periadventitially to the infrarenal aorta in mice and AAA was allowed to develop for 14 days. Nanoparticles loaded with PGG (EL-PGG-NPs) were then delivered via IV route at 14-day and 21-day (10 mg/kg of body weight). A control group of mice received no therapy. The targeting of NPs to the AAA site was confirmed with fluorescent dye marked NPs and gold NPs. Animals were sacrificed at 28-d. We found that targeted PGG therapy reversed the AAA by decreasing matrix metalloproteinases MMP-9 and MMP-2, and the infiltration of macrophages in the medial layer. The increase in diameter of the aorta was reversed to healthy controls. Moreover, PGG treatment restored degraded elastic lamina and increased the circumferential strain of aneurysmal aorta to the healthy levels.

CONCLUSION

Our results support that site-specific delivery of PGG with targeted nanoparticles can be used to treat already developed AAA. Such therapy can reverse inflammatory markers and restore arterial homeostasis.

An inflammatory stimulus sensitizes TRPA1 channel to increase cytokine release in human lung fibroblasts

External stimuli such as cigarette smoke and house dust mite are often involved in the development and exacerbation of asthma. These risk factors could activate or sensitize transient receptor potential channel ankyrin 1 (TRPA1), which are primarily expressed in neuronal structures but also in non-neuronal cells such as fibroblasts. However, the role of non-neuronal TRPA1 in the pathophysiology of airway diseases including asthma remains unclear. We investigated TRPA1 expression on human fibroblast cells and whether inflammatory mediators could modulate its function. This study utilized human lung fibroblast cell lines, Medical Research Council cell strain 5 (MRC-5) and HF19 cells frequently used on experimental studies regarding allergic and respiratory disorders. The human lung fibroblasts were stimulated with house dust mite (Der p1) or tumor necrosis factor alpha (TNF-α) for 24 h, and we quantified TRPA1 mRNA and protein by qRT-PCR and western blot analysis, respectively. TRPA1 mRNA expressions were upregulated after TNF-α treatment. Calcium imaging analysis revealed that TNF-α treatment apparently sensitized TRPA1-mediated calcium influx by TRPA1 agonist allyl isothiocyanate (AITC) and the selective TRPA1 channel blocker HC-030031 effectively reduced the calcium response. Lastly, TRPA1 activation was not only involved in increased IL-8 cytokine release, but also in upregulating gene expression of matrix metalloprotease 9 (MMP9) in the human lung fibroblasts treated with TNF-α Together, these results indicate that presence of inflammatory mediators such as TNF-α could upregulate the non-neuronal expression of TRPA1 on fibroblasts which may aggravate further the release of inflammatory cytokines observed in human airway diseases.

Intermittent Hypoxia Alleviates β-Aminopropionitrile Monofumarate Induced Thoracic Aortic Dissection in C57BL/6 Mice

OBJECTIVE

Thoracic aortic dissection (TAD) has a high mortality rate. Intermittent hypoxia (IH) triggers both harmful and beneficial effects in numerous physiological systems. The effects of IH on TAD development were explored in a mouse model.

METHODS

β-Aminopropionitrile monofumarate (BAPN) was used to induce TAD in C57BL/6 mice. Three week old male mice were treated with 1 g/kg/day BAPN in drinking water for four weeks and simultaneously subjected to IH (n = 30) (21%-5% O₂, 90 s/cycle, 10 h/day, IH + BAPN group) or normoxia (n = 30) (21% O₂, 24 h/day, BAPN group). Human VSMCs (HUASMCs) exposed to IH (30 min, 5% O₂)/re-oxygenation (30 min, 21% O²) cycles with a maximum of 60 min/cycle to detect the effect of IH on HIF-1α and LOX via HIF-1α-siRNA.

RESULTS

It was found that BAPN administration significantly increased the lumen size and wall thickness of aortas compared with the normal group, but was significantly reversed by IH exposure. Additionally, IH exposure significantly increased the survival rate of BAPN induced TAD (70% vs. 40%). Furthermore, IH exposure reduced BAPN induced elastin breaks and apoptosis of vascular smooth muscle cells. IH exposure also reversed BAPN induced upregulation of inflammation and extracellular matrix (ECM) degradation. Real time polymerase chain reaction (RT-PCR) confirmed that IH inhibited inflammation and ECM degradation related genes interleukin (IL)-1β, IL-6, cathepsin S (Cat S), and matrix metalloproteinase 9 (MMP-9), but upregulated the ECM synthesis related genes lysyl oxidase (LOX) and collagen type I alpha2 (Col1a2) compared with the BAPN group. In vitro results suggest that IH promotes the expression of LOX via HIF-1α.

CONCLUSION

The results suggest that IH alleviates BAPN induced TAD in C57BL/6 mice.

Pentagalloyl Glucose and Its Functional Role in Vascular Health: Biomechanics and Drug-Delivery Characteristics

Pentagalloyl glucose (PGG) is an elastin-stabilizing polyphenolic compound that has significant biomedical benefits, such as being a free radical sink, an anti-inflammatory agent, anti-diabetic agent, enzymatic resistant properties, etc. This review article focuses on the important benefits of PGG on vascular health, including its role in tissue mechanics, the different modes of pharmacological administration (e.g., oral, intravenous and endovascular route, intraperitoneal route, subcutaneous route, and nanoparticle based delivery and microbubble-based delivery), and its potential therapeutic role in vascular diseases such as abdominal aortic aneurysms (AAA). In particular, the use of PGG for AAA suppression and prevention has been demonstrated to be effective only in the calcium chloride rat AAA model. Therefore, in this critical review we address the challenges that lie ahead for the clinical translation of PGG as an AAA growth suppressor.