Lung Section Staining and Microscopy

Mechanosensitive channels TMEM63A and TMEM63B mediate lung inflation-induced surfactant secretion

Pulmonary surfactant is a lipoprotein complex lining the alveolar surface to decrease the surface tension and facilitate inspiration. Surfactant deficiency is often seen in premature infants and in children and adults with respiratory distress syndrome. Mechanical stretch of alveolar type 2 epithelial (AT2) cells during lung expansion is the primary physiological factor that stimulates surfactant secretion; however, it is unclear whether there is a mechanosensor dedicated to this process. Here, we show that loss of the mechanosensitive channels TMEM63A and TMEM63B (TMEM63A/B) resulted in atelectasis and respiratory failure in mice due to a deficit of surfactant secretion. TMEM63A/B were predominantly localized at the limiting membrane of the lamellar body (LB), a lysosome-related organelle that stores pulmonary surfactant and ATP in AT2 cells. Activation of TMEM63A/B channels during cell stretch facilitated the release of surfactant and ATP from LBs fused with the plasma membrane. The released ATP evoked Ca2+ signaling in AT2 cells and potentiated exocytic fusion of more LBs. Our study uncovered a vital physiological function of TMEM63 mechanosensitive channels in preparing the lungs for the first breath at birth and maintaining respiration throughout life.

Immune cells promote paralytic disease in mice infected with enterovirus D68

Enterovirus D68 (EV-D68) is associated with acute flaccid myelitis (AFM), a poliomyelitis-like illness causing paralysis in young children. However, mechanisms of paralysis are unclear, and antiviral therapies are lacking. To better understand EV-D68 disease, we inoculated newborn mice intracranially to assess viral tropism, virulence, and immune responses. Wild-type (WT) mice inoculated intracranially with a neurovirulent strain of EV-D68 showed infection of spinal cord neurons and developed paralysis. Spinal tissue from infected mice revealed increased levels of chemokines, inflammatory monocytes, macrophages, and T cells relative to controls, suggesting that immune cell infiltration influences pathogenesis. To define the contribution of cytokine-mediated immune cell recruitment to disease, we inoculated mice lacking CCR2, a receptor for several EV-D68-upregulated cytokines, or RAG1, which is required for lymphocyte maturation. WT, Ccr2 -/- , and Rag1 -/- mice had comparable viral titers in spinal tissue. However, Ccr2 -/- and Rag1 -/- mice had significantly less paralysis relative to WT mice. Consistent with impaired T cell recruitment to sites of infection in Ccr2 -/- and Rag1 -/- mice, antibody-mediated depletion of CD4 + or CD8 + T cells from WT mice diminished paralysis. These results indicate that immune cell recruitment to the spinal cord promotes EV-D68-associated paralysis and illuminate new targets for therapeutic intervention.

Monocyte Production of C1q Potentiates CD8+ T-Cell Function Following Respiratory Viral Infection

Respiratory viral infections remain a leading cause of morbidity and mortality. Using a murine model of human metapneumovirus, we identified recruitment of a C1q-expressing inflammatory monocyte population concomitant with viral clearance by adaptive immune cells. Genetic ablation of C1q led to reduced CD8+ T-cell function. Production of C1q by a myeloid lineage was necessary to enhance CD8+ T-cell function. Activated and dividing CD8+ T cells expressed a C1q receptor, gC1qR. Perturbation of gC1qR signaling led to altered CD8+ T-cell IFN-γ production, metabolic capacity, and cell proliferation. Autopsy specimens from fatal respiratory viral infections in children exhibited diffuse production of C1q by an interstitial population. Humans with severe coronavirus disease (COVID-19) infection also exhibited upregulation of gC1qR on activated and rapidly dividing CD8+ T cells. Collectively, these studies implicate C1q production from monocytes as a critical regulator of CD8+ T-cell function following respiratory viral infection.

Progesterone (P4) ameliorates cigarette smoke-induced chronic obstructive pulmonary disease (COPD)

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory lung disease associated with high morbidity and mortality worldwide. Oxidative injury and mitochondrial dysfunction in the airway epithelium are major events in COPD progression.

METHODS AND RESULTS

The therapeutic effects of Progesterone (P4) were investigated in vivo and in vitro in this study. In vivo, in a cigarette smoke (CS) exposure-induced COPD mouse model, P4 treatment significantly ameliorated CS exposure-induced physiological and pathological characteristics, including inflammatory cell infiltration and oxidative injury, in a dose-dependent manner. The c-MYC/SIRT1/PGC-1α pathway is involved in the protective function of P4 against CS-induced COPD. In vitro, P4 co-treatment significantly ameliorated H2O2-induced oxidative injury and mitochondrial dysfunctions by promoting cell proliferation, increasing mitochondrial membrane potential, decreasing ROS levels and apoptosis, and increasing ATP content. Moreover, P4 co-treatment partially attenuated H2O2-caused inhibition in Nrf1, Tfam, Mfn1, PGR-B, c-MYC, SIRT1, and PGC-1α levels. In BEAS-2B and ASM cells, the c-MYC/SIRT1 axis regulated P4's protective effects against H2O2-induced oxidative injury and mitochondrial dysfunctions.

CONCLUSION

P4 activates the c-MYC/SIRT1 axis, ameliorating CS-induced COPD and protecting both airway epithelial cells and smooth muscle cells against H2O2-induced oxidative damage. PGC-1α and downstream mitochondrial signaling pathways might be involved.

Click method preserves but EDC method compromises the therapeutic activities of the peptide-activated hydrogels for critical ischemic vessel regeneration

Peptide-functionalized hydrogel is one of commonly used biomaterials to introduce hydrogel-induced vessel regeneration. Despite many reports about the discoveries of high-active peptides (or ligands) for regeneration, the study on the conjugating methods for the hydrogel functionalization with peptides is limited. Here, we compared the vasculogenic efficacy of the peptide-functionalized hydrogels prepared by two commonly used conjugating methods, 1-ethyl-3-(3-dimethylamino propyl) carbodiimide (EDC) and Click methods, through cell models, organ-on-chips models, animal models, and RNA sequencing analysis. Two vascular-related cell types, the human umbilical vein endothelial cells (HUVECs) and the adipose-derived stem cells (ADSCs), have been cultured on the hydrogel surfaces prepared by EDC/Click methods. It showed that the hydrogels prepared by Click method supported the higher vasculogenic activities while the ones made by EDC method compromised the peptide activities on hydrogels. The vasculogenesis assays further revealed that hydrogels prepared by Click method promoted a better vascular network formation. In a critical ischemic hindlimb model, only the peptide-functionalized hydrogels prepared by Click method successfully salvaged the ischemic limb, significantly improved blood perfusion, and enhanced the functional recoveries (through gait analysis and animal behavior studies). RNA sequencing studies revealed that the hydrogels prepared by Click method significantly promoted the PI3K-AKT pathway activation compared to the hydrogels prepared by EDC method. All the results suggested that EDC method compromised the functions of the peptides, while Click method preserved the vascular regenerating capacities of the peptides on the hydrogels, illustrating the importance of the conjugating method during the preparation of the peptide-functionalized hydrogels.

Non-allergic eosinophilic inflammation and airway hyperresponsiveness induced by diesel engine exhaust through activating ILCs

RATIONALE

Diesel engine exhaust (DEE) is associated with the development and exacerbation of asthma. Studies have shown that DEE can aggravate allergen-induced eosinophilic inflammation in lung. However, it remains not clear that whether DEE alone could initiate non-allergic eosinophilic inflammation and airway hyperresponsiveness (AHR) through innate lymphoid cells (ILCs) pathway.

OBJECTIVE

This study aims to investigate the airway inflammation and hyperresponsiveness and its relationship with ILC after DEE exposure.

METHOD

Non-sensitized BALB/c mice were exposed in the chamber of diesel exhaust or filtered air for 2, 4, and 6 weeks (4 h/day, 6 days/week). Anti-CD4 mAb or anti-Thy1.2 mAb was administered by intraperitoneal injection to inhibit CD4+T or ILCs respectively. AHR、airway inflammation and ILCs were assessed.

RESULT

DEE exposure induced significantly elevated level of neutrophils, eosinophils, collagen content at 4, 6 weeks. Importantly, the airway AHR was only significant in the 4weeks-DEE exposure group. No difference of the functional proportions of Th2 cells was found between exposure group and control group. The proportions of IL-5+ILC2, IL-17+ILC significantly increased in 2, 4weeks-DEE exposure group. After depletion of CD4+T cells, both the proportion of IL-5+ILC2 and IL-17A ILCs was higher in the 4weeks-DEE exposure group which induced AHR, neutrophilic and eosinophilic inflammation accompanied by the IL-5, IL-17A levels.

CONCLUSION

Diesel engine exhaust alone can imitate asthmatic characteristics in mice model. Lung-resident ILCs are one of the major effectors cells responsible for a mixed Th2/Th17 response and AHR.

Neutrophils and galectin-3 defend mice from lethal bacterial infection and humans from acute respiratory failure

Respiratory infection by Pseudomonas aeruginosa, common in hospitalized immunocompromised and immunocompetent ventilated patients, can be life-threatening because of antibiotic resistance. This raises the question of whether the host's immune system can be educated to combat this bacterium. Here we show that prior exposure to a single low dose of lipopolysaccharide (LPS) protects mice from a lethal infection by P. aeruginosa. LPS exposure trained the innate immune system by promoting expansion of neutrophil and interstitial macrophage populations distinguishable from other immune cells with enrichment of gene sets for phagocytosis- and cell-killing-associated genes. The cell-killing gene set in the neutrophil population uniquely expressed Lgals3, which encodes the multifunctional antibacterial protein, galectin-3. Intravital imaging for bacterial phagocytosis, assessment of bacterial killing and neutrophil-associated galectin-3 protein levels together with use of galectin-3-deficient mice collectively highlight neutrophils and galectin-3 as central players in LPS-mediated protection. Patients with acute respiratory failure revealed significantly higher galectin-3 levels in endotracheal aspirates (ETAs) of survivors compared to non-survivors, galectin-3 levels strongly correlating with a neutrophil signature in the ETAs and a prognostically favorable hypoinflammatory plasma biomarker subphenotype. Taken together, our study provides impetus for harnessing the potential of galectin-3-expressing neutrophils to protect from lethal infections and respiratory failure.

Aprepitant Alleviates Poststroke Pneumonia in a Mouse Model of Middle Cerebral Artery Occlusion

Elevated substance P can be utilized to predict early mortality during the first week of cerebral infarction. Whether aprepitant, a substance P receptor blocker could be utilized to alleviate poststroke pneumonia which is investigated in this study. Intraluminal monofilament model of middle cerebral artery occlusion (MCAO) was constructed in C57BL/6J male mice, and the relative expression of substance P was detected in collected bronchoalveolar lavage fluid (BALF) and lung tissue homogenate at 24 hours, 48 hours, and 72 hours poststroke. On the other hand, different concentrations of aprepitant (0.5, 1, and 2 mg/kg) were atomized and inhaled into MCAO mice. Inflammation cytokines and bacterial load were detected in collected BALF and lung tissue homogenate at 72-hour poststroke, and lung injury was revealed by histological examination. Aprepitant administration decreased total proteins, total cells, neutrophils, and macrophages in BALF. The concentrations of interleukin (IL)-6, IL-1β, tumor necrosis factor-α, interferon γ, monocyte chemoattractant protein-1, and IL-10 in lung tissue homogenates were also diminished by the administration of aprepitant. In conclusion, aprepitant could attenuate poststroke pneumonia in mice suggesting its potential therapeutic use in the clinic.

Aerobic exercise training engages the canonical wnt pathway to improve pulmonary function and inflammation in COPD

BACKGROUND

We studied whether the exercise improves cigarette smoke (CS) induced chronic obstructive pulmonary disease (COPD) in mice through inhibition of inflammation mediated by Wnt/β-catenin-peroxisome proliferator-activated receptor (PPAR) γ signaling.

METHODS

Firstly, we observed the effect of exercise on pulmonary inflammation, lung function, and Wnt/β-catenin-PPARγ. A total of 30 male C57BL/6J mice were divided into the control group (CG), smoke group (SG), low-intensity exercise group (LEG), moderate-intensity exercise group (MEG), and high-intensity exercise group (HEG). All the groups, except for CG, underwent whole-body progressive exposure to CS for 25 weeks. Then, we assessed the maximal exercise capacity of mice from the LEG, MEG, and HEG, and performed an 8-week treadmill exercise intervention. Then, we used LiCl (Wnt/β-catenin agonist) and XAV939 (Wnt/β-catenin antagonist) to investigate whether Wnt/β-catenin-PPARγ pathway played a role in the improvement of COPD via exercise. Male C57BL/6J mice were randomly divided into six groups (n = 6 per group): CG, SG, LiCl group, LiCl and exercise group, XAV939 group, and XAV939 and exercise group. Mice except those in the CG were exposed to CS, and those in the exercise groups were subjected to moderate-intensity exercise training. All the mice were subjected to lung function test, lung histological assessment, and analysis of inflammatory markers in the bronchoalveolar lavage fluid, as well as detection of Wnt1, β-catenin and PPARγ proteins in the lung tissue.

RESULTS

Exercise of various intensities alleviated lung structural changes, pulmonary function and inflammation in COPD, with moderate-intensity exercise exhibiting significant and comprehensive effects on the alleviation of pulmonary inflammation and improvement of lung function. Low-, moderate-, and high-intensity exercise decreased β-catenin levels and increased those of PPARγ significantly, and only moderate-intensity exercise reduced the level of Wnt1 protein. Moderate-intensity exercise relieved the inflammation aggravated by Wnt agonist. Wnt antagonist combined with moderate-intensity exercise increased the levels of PPARγ, which may explain the highest improvement of pulmonary function observed in this group.

CONCLUSIONS

Exercise effectively decreases COPD pulmonary inflammation and improves pulmonary function. The beneficial role of exercise may be exerted through Wnt/β-catenin-PPARγ pathway.

Inhibiting Eph/ephrin signaling reduces vascular leak and endothelial cell dysfunction in mice with sepsis

Sepsis is a life-threatening disease caused by a dysregulated host response to infection, resulting in 11 million deaths globally each year. Vascular endothelial cell dysfunction results in the loss of endothelial barrier integrity, which contributes to sepsis-induced multiple organ failure and mortality. Erythropoietin-producing hepatocellular carcinoma (Eph) receptors and their ephrin ligands play a key role in vascular endothelial barrier disruption but are currently not a therapeutic target in sepsis. Using a cecal ligation and puncture (CLP) mouse model of sepsis, we showed that prophylactic or therapeutic treatment of mice with EphA4-Fc, a decoy receptor and pan-ephrin inhibitor, resulted in improved survival and a reduction in vascular leak, lung injury, and endothelial cell dysfunction. EphA2-/- mice also exhibited reduced mortality and pathology after CLP compared with wild-type mice. Proteomics of plasma samples from mice with sepsis after CLP revealed dysregulation of a number of Eph/ephrins, including EphA2/ephrin A1. Administration of EphA4-Fc to cultured human endothelial cells pretreated with TNF-α or ephrin-A1 prevented loss of endothelial junction proteins, specifically VE-cadherin, with maintenance of endothelial barrier integrity. In children admitted to hospital with fever and suspected infection, we observed that changes in EphA2/ephrin A1 in serum samples correlated with endothelial and organ dysfunction. Targeting Eph/ephrin signaling may be a potential therapeutic strategy to reduce sepsis-induced endothelial dysfunction and mortality.

Nanoparticles of Lactiplantibacillus plantarum K8 Reduce Staphylococcus aureus Respiratory Infection and Tumor Necrosis Factor Alpha- and Interferon Gamma-Induced Lung Inflammation

Multiple studies have confirmed that Lactiplantibacillus plantarum has beneficial effects in respiratory diseases, including respiratory tract infections, asthma, and chronic obstructive pulmonary disease. However, the role of L. plantarum lysates in respiratory diseases is unclear. Staphylococcus aureus infects the lungs of mice, recruits immune cells, and induces structural changes in alveoli. Lung diseases can be further aggravated by inflammatory cytokines such as CCL2 and interleukin (IL)-6. In in vivo studies, L. plantarum K8 nanoparticles (K8NPs) restored lung function and prevented lung damage caused by S. aureus infection. They inhibited the S. aureus infection and the infiltration of immune cells and prevented the increase in goblet cell numbers in the lungs of S. aureus-infected mice. K8NPs suppressed the expression of CCL2 and IL-6, which were increased by the combination treatment of tumor necrosis factor alpha and interferon gamma (TI), in a dose-dependent manner. In in vitro studies, the anti-inflammatory effect of K8NPs in TI-treated A549 cells and TI-injected mice occurred through the reduction in activated mitogen-activated protein kinases and nuclear factor kappa-B. These findings suggest that the efficacy of K8NPs in controlling respiratory inflammation and infection can be used to develop functional materials that can prevent or alleviate respiratory diseases.

Angiotensin-(1-7) suppresses airway inflammation and airway remodeling via inhibiting ATG5 in allergic asthma

BACKGROUND

Angiotensin (Ang)-(1-7) can reduce airway inflammation and airway remodeling in allergic asthma. Autophagy-related 5 (ATG5) has attracted wide attentions in asthma. However, the effects of Ang-(1-7) on ATG5-mediated autophagy in allergic asthma are unclear.

METHODS

In this study, human bronchial epithelial cell (BEAS-2B) and human bronchial smooth muscle cell (HBSMC) were treated with different dose of Ang-(1-7) to observe changes of cell viability. Changes of ATG5 protein expression were measured in 10 ng/mL of interleukin (IL)-13-treated cells. Transfection of ATG5 small interference RNA (siRNA) or ATG5 cDNA in cells was used to analyze the effects of ATG5 on secretion of cytokines in the IL-13-treated cells. The effects of Ang-(1-7) were compared to the effects of ATG5 siRNA transfection or ATG5 cDNA transfection in the IL-13-treated cells. In wild-type (WT) mice and ATG5 knockout (ATG5-/-) mice, ovalbumin (OVA)-induced airway inflammation, fibrosis and autophagy were observed. In the OVA-induced WT mice, Ang-(1-7) treatment was performed to observe its effects on airway inflammation, fibrosis and autophagy.

RESULTS

The results showed that ATG5 protein level was decreased with Ang-(1-7) dose administration in the IL-13-treated BEAS-2B and IL13-treated HBSMC. Ang-(1-7) played similar results to ATG5 siRNA that it suppressed the secretion of IL-25 and IL-13 in the IL-13-treated BEAS-2B cells, and inhibited the expression of transforming growth factor (TGF)-β1 and α-smooth muscle actin (α-SMA) protein in the IL-13-treated HBSMC cells. ATG5 cDNA treatment significantly increased the secretion of IL-25 and IL-13 and expression of TGF-β1 and α-SMA protein in IL-13-treated cells. Ang-(1-7) treatment suppressed the effects of ATG5 cDNA in the IL-13-treated cells. In OVA-induced WT mice, Ang-(1-7) treatment suppressed airway inflammation, remodeling and autophagy. ATG5 knockout also suppressed the airway inflammation, remodeling and autophagy.

CONCLUSIONS

Ang-(1-7) treatment suppressed airway inflammation and remodeling in allergic asthma through inhibiting ATG5, providing an underlying mechanism of Ang-(1-7) for allergic asthma treatment.

PLK1 inhibition dampens NLRP3 inflammasome-elicited response in inflammatory disease models

Unabated activation of the NLR family pyrin domain-containing 3 (NLRP3) inflammasome is linked with the pathogenesis of various inflammatory disorders. Polo-like kinase 1 (PLK1) has been widely studied for its role in mitosis. Here, using both pharmacological and genetic approaches, we demonstrate that PLK1 promoted NLRP3 inflammasome activation at cell interphase. Using an unbiased proximity-dependent biotin identification (Bio-ID) screen for the PLK1 interactome in macrophages, we show an enhanced proximal association of NLRP3 with PLK1 upon NLRP3 inflammasome activation. We further confirmed the interaction between PLK1 and NLRP3 and identified the interacting domains. Mechanistically, we show that PLK1 orchestrated the microtubule-organizing center (MTOC) structure and NLRP3 subcellular positioning upon inflammasome activation. Treatment with a selective PLK1 kinase inhibitor suppressed IL-1β production in in vivo inflammatory models, including LPS-induced endotoxemia and monosodium urate-induced peritonitis in mice. Our results uncover a role of PLK1 in regulating NLRP3 inflammasome activation during interphase and identify pharmacological inhibition of PLK1 as a potential therapeutic strategy for inflammatory diseases with excessive NLRP3 inflammasome activation.

Noninvasive mechanical destruction of liver tissue and tissue decellularisation by pressure-modulated shockwave histotripsy

Introduction

Boiling histotripsy (BH) is a promising High Intensity Focused Ultrasound (HIFU) technique that can be used to mechanically fractionate solid tumours at the HIFU focus noninvasively, promoting tumour immunity. Because of the occurrence of shock scattering phenomenon during BH process, the treatment accuracy of BH is, however, somewhat limited. To induce more localised and selective tissue destruction, the concept of pressure modulation has recently been proposed in our previous in vitro tissue phantom study. The aim of the present study was therefore to investigate whether this newly developed histotripsy approach termed pressure-modulated shockwave histotripsy (PSH) can be used to induce localised mechanical tissue fractionation in in vivo animal model.

Methods

In the present study, 8 Sprague Dawley rats underwent the PSH treatment and were sacrificed immediately after the exposure for morphological and histological analyses (paraffin embedded liver tissue sections were stained with H&E and MT). Partially exteriorised rat's left lateral liver lobe in vivo was exposed to a 2.0 MHz HIFU transducer with peak positive (P ₊) and negative (P _-) pressures of 89.1 MPa and -14.6 MPa, a pulse length of 5 to 34 ms, a pressure modulation time at 4 ms where P ₊ and P _- decreased to 29.9 MPa and - 9.6 MPa, a pulse repetition frequency of 1 Hz, a duty cycle of 1% and number of pulses of 1 to 20. Three lesions were produced on each animal. For comparison, the same exposure condition but no pressure modulation was also employed to create a number of lesions in the liver.

Results and Discussion

Experimental results showed that a partial mechanical destruction of liver tissue in the form of an oval in the absence of thermal damage was clearly observed at the HIFU focus after the PSH exposure. With a single pulse length of 7 ms, a PSH lesion created in the liver was measured to be a length of 1.04 ± 0.04 mm and a width of 0.87 ± 0.21 mm which was 2.37 times in length (p = 0.027) and 1.35 times in width (p = 0.1295) smaller than a lesion produced by no pressure modulation approach (e.g., BH). It was also observed that the length of a PSH lesion gradually grew towards the opposite direction to the HIFU source along the axial direction with the PSH pulse length, eventually leading to the generation of an elongated lesion in the liver. In addition, our experimental results demonstrated the feasibility of inducing partial decellularisation effect where liver tissue was partially destructed with intact extracellular matrix (i.e., intact fibrillar collagen) with the shortest PSH pulse length. Taken together, these results suggest that PSH could be used to induce a highly localised tissue fractionation with a desired degree of mechanical damage from complete tissue fractionation to tissue decellularisation through controlling the dynamics of boiling bubbles without inducing the shock scattering effect.

High-CBD Cannabis Vapor Attenuates Opioid Reward and Partially Modulates Nociception in Female Rats

Chronic pain patients report analgesic effects when using cannabidiol (CBD), a phytocannabinoid found in whole-plant cannabis extract (WPE). Several studies suggest that cannabis-derived products may serve as an analgesic adjunct or alternative to opioids, and importantly, CBD may also attenuate the abuse potential of opioids. Vaping is a popular route of administration among people who use cannabis, however both the therapeutic and hazardous effects of vaping are poorly characterized. Despite the fact that chronic pain is more prevalent in women, the ability of inhaled high-CBD WPE to relieve pain and reduce opioid reward has not been studied in females. Here, we present a comprehensive analysis of high-CBD WPE vapor inhalation in female rats. We found that WPE was modestly efficacious in reversing neuropathy-induced cold allodynia in rats with spared nerve injury (SNI). Chronic exposure to WPE did not affect lung cytoarchitecture or estrous cycle, and it did not induce cognitive impairment, social withdrawal or anxiolytic effects. WPE inhalation prevented morphine-induced conditioned place preference and reinstatement. Similarly, WPE exposure reduced fentanyl self-administration in rats with and without neuropathic pain. We also found that WPE vapor lacks of reinforcing effects compared to the standard excipient used in most vapor administration research. Combined, these results suggest that although high-CBD vapor has modest analgesic effects, it has a robust safety profile, no abuse potential, and it significantly reduces opioid reward in females. Clinical studies examining high-CBD WPE as an adjunct treatment during opioid use disorder are highly warranted.

β-sitosterol targets glucocorticoid receptor to reduce airway inflammation and remodeling in allergic asthma

INTRODUCTION

In most asthma patients, symptoms are controlled by treatment with glucocorticoid, but long-term or high-dose use can produce adverse effects. Therefore, it is crucial to find new therapeutic strategies. β-sitosterol could suppress type Ⅱ inflammation in ovalbumin (OVA)-induced mice, but its mechanisms have remained unclear.

METHODS

A binding activity of β-sitosterol with glucocorticoid receptor (GR) was analyzed by molecular docking. Human bronchial epithelial cells (BEAS-2B) and human bronchial smooth muscle cells (HBSMC) were treated with different concentrations (0, 1, 5, 10, 20, and 50 μg/mL) of β-sitosterol for suitable concentration selection. In transforming growth factor (TGF)-β1 treated BEAS-2B and HBSMC, cells were treated with 20 μg/mL β-sitosterol or dexamethasone (Dex) to analyze its possible mechanism. In OVA-induced mice, 2.5 mg/kg β-sitosterol or Dex administration was performed to analyze the therapeutic mechanism of β-sitosterol. A GR antagonist RU486 was used to confirm the mechanism of β-sitosterol in the treatment of asthma.

RESULTS

A good binding of β-sitosterol to GR (score = -8.2 kcal/mol) was found, and the GR expression was upregulated with β-sitosterol dose increase in BEAS-2B and HBSMC. Interleukin (IL)-25 and IL-33 secretion was significantly decreased by β-sitosterol in the TGF-β1-induced BEAS-2B, and the levels of collagen 1A and α-smooth muscle actin (SMA) were reduced in the TGF-β1-induced HBSMC. In the OVA-challenged mice, β-sitosterol treatment improved airway inflammation and remodeling through suppressing type Ⅱ immune response and collagen deposition. The therapeutic effects of β-sitosterol were similar to Dex treatment in vitro and in vivo. RU486 treatment clearly hampered the therapeutic effects of β-sitosterol in the TGF-β1-induced cells and OVA-induced mice.

CONCLUSION

This study identified that β-sitosterol binds GR to perform its functions in asthma treatment. β-sitosterol represent a potential therapeutic drug for allergic asthma.

Kaempferol inhibits airway inflammation induced by allergic asthma through NOX4-Mediated autophagy

BACKGROUND

Kaempferol has important medicinal value in the treatment of asthma. However, its mechanism of action has not been fully understood and needs to be explored and studied.

METHODS

A binding activity of kaempferol with nicotinamide adenine dinucleotide phosphate oxidase 4 (NOX4) was analyzed by molecular docking. Human bronchial epithelial cells (BEAS-2B) were treated with different concentrations (0, 1, 5, 10, 20, 40 μg/mL) of kaempferol to select its suitable concentration. In the transforming growth factor (TGF)-β1-induced BEAS-2B, cells were treated with 20 μg/mL kaempferol or 20 μM GLX35132 (a NOX4 inhibitor) to analyze its effects on NOX4-mediated autophagy. In the ovalbumin (OVA)-induced mice, 20 mg/kg kaempferol or 3.8 mg/kg GLX351322 administration was performed to analyze the therapeutic effects of kaempferol on NOX4-mediated autophagy. An autophagy activator, rapamycin, was used to confirm the mechanism of kaempferol in treatment of allergic asthma.

RESULTS

A good binding of kaempferol to NOX4 (score = -9.2 kcal/mol) was found. In the TGF-β1-induced BEAS-2B, the NOX4 expression was decreased with kaempferol dose increase. The secretions of IL-25 and IL-33, and the NOX4-mediated autophagy were significantly decreased by kaempferol treatment in the TGF-β1-induced BEAS-2B. In the OVA-challenged mice, kaempferol treatment improved airway inflammation and remodeling through suppressing NOX4-mediated autophagy. The rapamycin treatment clearly hampered the therapeutic effects of kaempferol in the TGF-β1-induced cells and OVA-induced mice.

CONCLUSIONS

This study identifies kaempferol binds NOX4 to perform its functions in the treatment of allergic asthma, providing an effective therapeutic strategy in the further treatment of asthma.

Efficacy of COVID-HIGIV in animal models of SARS-CoV-2 infection

In late 2019 the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus emerged in China and quickly spread into a worldwide pandemic. It has caused millions of hospitalizations and deaths, despite the use of COVID-19 vaccines. Convalescent plasma and monoclonal antibodies emerged as major therapeutic options for treatment of COVID-19. We have developed an anti-SARS-CoV-2 immunoglobulin intravenous (Human) (COVID-HIGIV), a potential improvement from using convalescent plasma. In this report the efficacy of COVID-HIGIV was evaluated in hamster and mouse models of SARS-CoV-2 infection. COVID-HIGIV treatment in both mice and hamsters significantly reduced the viral load in the lungs. Among COVID-HIGIV treated animals, infection-related body weight loss was reduced and the animals regained their baseline body weight faster than the PBS controls. In hamsters, COVID-HIGIV treatment reduced infection-associated lung pathology including lung inflammation, and pneumocyte hypertrophy in the lungs. These results support ongoing trials for outpatient treatment with COVID-HIGIV for safety and efficacy evaluation (NCT04910269, NCT04546581).

Injectable Antibacterial Gelatin-Based Hydrogel Incorporated with Two-Dimensional Nanosheets for Multimodal Healing of Bacteria-Infected Wounds

The design and development of multifunctional injectable hydrogels with high photothermal antibacterial activity and shape adaptability to accelerate bacteria-infected wound healing is of critical importance in clinical applications. In this study, a hybrid hydrogel composed of gelatin, iron, and MnO2 nanosheets was prepared by multiple interactions, including coordinative and hydrogen bonding as well as electrostatic attraction. The introduced MnO2 and Fe components made the hydrogels photothermally and chemodynamically active, thereby endowing them with potent antibacterial capabilities against both Gram-negative and Gram-positive bacteria. Because of the Fenton activity of the hydrogels, they could produce abandoned oxygen, which is highly crucial in the healing process of wounds. They also showed good cytocompatibility and hemocompatibility as well as high hemostatic properties. Moreover, the injectable hydrogels could fill irregular wounds and significantly accelerate bacteria-infected wound healing through decreasing the inflammatory response and increasing blood vessels. These features indicated the promising potential of the multifunctional hydrogel for healing infected full-thickness wounds.

Regulation of hyperoxia-induced neonatal lung injury via post-translational cysteine redox modifications

Preterm infants and patients with lung disease often have excess fluid in the lungs and are frequently treated with oxygen, however long-term exposure to hyperoxia results in irreversible lung injury. Although the adverse effects of hyperoxia are mediated by reactive oxygen species, the full extent of the impact of hyperoxia on redox-dependent regulation in the lung is unclear. In this study, neonatal mice overexpressing the beta-subunit of the epithelial sodium channel (β-ENaC) encoded by Scnn1b and their wild type (WT; C57Bl6) littermates were utilized to study the pathogenesis of high fraction inspired oxygen (FiO2)-induced lung injury. Results showed that O2-induced lung injury in transgenic Scnn1b mice is attenuated following chronic O2 exposure. To test the hypothesis that reversible cysteine-redox-modifications of proteins play an important role in O2-induced lung injury, we performed proteome-wide profiling of protein S-glutathionylation (SSG) in both WT and Scnn1b overexpressing mice maintained at 21% O2 (normoxia) or FiO2 85% (hyperoxia) from birth to 11-15 days postnatal. Over 7700 unique Cys sites with SSG modifications were identified and quantified, covering more than 3000 proteins in the lung. In both mouse models, hyperoxia resulted in a significant alteration of the SSG levels of Cys sites belonging to a diverse range of proteins. In addition, substantial SSG changes were observed in the Scnn1b overexpressing mice exposed to hyperoxia, suggesting that ENaC plays a critically important role in cellular regulation. Hyperoxia-induced SSG changes were further supported by the results observed for thiol total oxidation, the overall level of reversible oxidation on protein cysteine residues. Differential analyses reveal that Scnn1b overexpression may protect against hyperoxia-induced lung injury via modulation of specific processes such as cell adhesion, blood coagulation, and proteolysis. This study provides a landscape view of protein oxidation in the lung and highlights the importance of redox regulation in O2-induced lung injury.

Investigation of the long-term healing response of the liver to boiling histotripsy treatment in vivo

Boiling histotripsy (BH) is a promising High-Intensity Focused Ultrasound technique that can be employed to mechanically fractionate solid tumours. Whilst studies have shown the feasibility of BH to destroy liver cancer, no study has reported on the healing process of BH-treated liver tissue. We therefore extensively investigated the evolution of the healing response of liver to BH in order to provide an insight into the healing mechanisms. In the present study, 14 Sprague Dawley rats underwent the BH treatment and were sacrificed on days 0, 3, 7, 14, and 28 for morphological, histological, serological and qPCR analyses. The area of the treated region was 1.44 cm² (1.2 cm × 1.2 cm). A well-defined BH lesion filled with coagulated blood formed on day 0. A week after the treatment, fibroblast activation was induced at the treatment site, leading to the formation of extracellular matrix structure (ECM). The ECM was then disrupted for 7 to 28 days. Regenerated normal hepatocytes and newly formed blood vessels were found within the BH region with the absence of hepatic fibrosis. No significant morphological, histological and genetic changes around the BH lesion occurred. These results suggest that BH could be a safe and promising therapeutic tool for treating solid tumours without inducing any significant adverse effect such as the formation of liver fibrosis.

Modulatory apoptotic effects of sinomenine on Mycoplasma pneumonia through the attenuation of inflammation via ERK/JNK/NF-κB signaling pathway

Mycoplasma pneumoniae (MPP) induced pneumonia is a common disease of children. Sinomenine (SIN) is an isoquinoline mainly sequestered from Sinomenium acutum. It is a promising drug for treating arthritis, lung, colon, liver and gastric cancer. Hence, the present study investigated the role and mechanism of SIN treatment in MPP induced pneumonia in experimental in-vivo mice model. The BALB/c male mice were separated into four groups (n = 6 mice/group): normal, MPP, MPP + SIN (20 mg/kg bw), and SIN (20 mg/kg bw) alone. Results were expressed as mean ± SD. Data were analyzed using one way Analysis of Variance (ANOVA) with the Dunnett's post hoc test using SPSS v 18.0. P value < 0.05 was considered significant. The total protein, cell count, inflammatory cytokines, MP-IgM, Monocyte chemo attractant protein-1 (MCP-1), and MP-DNA were measured. The protein expressions of Bax/Bcl-2, ERK, JNK, NF-κB were analyzed and histopathology of lungs was examined. SIN treatment significantly (p < 0.05) reduced the total proteins, cell counts in BALF, inflammatory cytokines, MP-IgM, MCP-1, MP-DNA and reversed the histological alterations. SIN attenuated the apoptotic pathway through the modulation of Bax/Bcl-2 expression. SIN alleviated pulmonary inflammatory mediators and apoptosis in MPP-infected mice via suppression of ERK/JNK/NF-κB signaling. SIN administration diminished inflammation and lung fibrosis by inhibiting apoptosis in MPP mice. Hence, SIN is a potential natural protective remedy for MPP.

Hydrophilic Poly(glutamic acid)-Based Nanodrug Delivery System: Structural Influence and Antitumor Efficacy

Poly(amino acids) have advanced characteristics, including unique secondary structure, enzyme degradability, good biocompatibility, and stimuli responsibility, and are suitable as drug delivery nanocarriers for tumor therapy. The isoform structure of poly(amino acids) plays an important role in their antitumor efficacy and should be researched in detail. In this study, two kinds of pH-sensitive isoforms, including α-poly(glutamic acid) (α-PGA) and γ-PGA, were selected and used as nanocarriers to prepare a nanodrug delivery system. According to the preparation results, α-PGA can be used as an ideal drug carrier. Selecting doxorubicin (DOX) as the model drug, an α-PGA/DOX nanoparticle (α-PGA/DOX NPs) with a particle size of 110.4 nm was prepared, and the drug-loading content was 66.2%. α-PGA/DOX NPs presented obvious sustained and pH-dependent release characteristics. The IC50 value of α-PGA/DOX NPs was 1.06 ± 0.77 μg mL-1, decreasing by approximately 8.5 fold in vitro against 4T1 cells after incubation for 48 h. Moreover, α-PGA/DOX NPs enhanced antitumor efficacy in vivo, the tumor inhibition rate was 67.4%, increasing 1.5 fold over DOX injection. α-PGA/DOX NPs also reduced the systemic toxicity and cardiotoxicity of DOX. In sum, α-PGA is a biosafe nanodrug delivery carrier with potential clinical application prospects.

Label-free Raman spectroscopy characterizes signatures of inflammation and fibrosis in the silicosis

Silicosis is an occupational disease that seriously damages the life and health of miners. Herein, we constructed a mouse model of silicosis and used label-free confocal Raman spectroscopy to analyze the biomolecular variations in lung fibrous nodules and inflammatory sites. The mice were exposed to silica particles for 1 month (SIL-1M group), 3 months (SIL-3M group), or no exposure (control tissues, NS). Raman spectra obtained from treated and untreated lung tissue were subjected to chemometric analysis to quantify biochemical composition differences in the silicosis. Simultaneously, immunohistochemistry and collagen staining were used to evaluate inflammation, fibrosis, and apoptosis. As a result, the SIL-1M and SIL-3M groups showed significant differences in cholesterol, lipids, amino acids, nucleic acids, and cytochrome C, and the collagen peaks at 1248 cm^-1 and 1448 cm^-1 were significantly higher than in the NS group. Notably, glycogen and phospholipid may be an inflammatory indicator consistent with NF-κB expression. In addition, significant differences in collagen and cytochrome C content in silicosis lung tissue were found using Raman spectroscopy and were verified by Masson's staining and Bax/Bcl-2 expression ratio. In summary, our findings provide a label-free technique to understand the biochemical changes in lung inflammatory and fibrosis microenvironment after exposure to silica particles and provide a valuable reference for studying the mechanism of silicosis.

The “Second Hit” of Repair in a Rabbit Model of Chronic Rotator Cuff Tear

The rabbit supraspinatus is a useful translational model for rotator cuff (RC) repair because it recapitulates muscle atrophy and fat accumulation observed in humans after a chronic tear (the “first hit”). However, a timeline of RC tissue response after repair, especially with regard to recent evidence of muscle degeneration and lack of regeneration, is currently unavailable. Thus, the purpose of this study was to characterize the progression of muscle and fat changes over time after the repair of a chronic RC tear in the rabbit model. Two rounds of experiments were conducted in 2017–2018 and 2019–2020 with N = 18 and 16 skeletally mature New Zealand White rabbits, respectively. Animals underwent left supraspinatus tenotomy with repair 8 weeks later. The unoperated right shoulder served as control. The rabbits were sacrificed at 1-, 2-, 4-, and 8-weeks post-repair for histological and biochemical analysis. Atrophy, measured by fiber cross-sectional area and muscle mass, was greatest around 2 weeks after repair. Active muscle degeneration peaked at the same time, involving 8% of slide areas. There was no significant regeneration at any timepoint. Fat accumulation and fibrosis were significantly increased across all time points compared to contralateral. Statement of Clinical Significance: These results demonstrate model reproducibility and a “second hit” phenomenon of repair-induced muscle atrophy and degeneration which partially recovers after a short time, while increased fat and fibrosis persist.

Discovery of an Oxycyclohexyl Acid Lysophosphatidic Acid Receptor 1 (LPA1) Antagonist BMS-986278 for the Treatment of Pulmonary Fibrotic Diseases

The oxycyclohexyl acid BMS-986278 (33) is a potent lysophosphatidic acid receptor 1 (LPA₁) antagonist, with a human LPA₁ K_b of 6.9 nM. The structure-activity relationship (SAR) studies starting from the LPA₁ antagonist clinical compound BMS-986020 (1), which culminated in the discovery of 33, are discussed. The detailed in vitro and in vivo preclinical pharmacology profiles of 33, as well as its pharmacokinetics/metabolism profile, are described. On the basis of its in vivo efficacy in rodent chronic lung fibrosis models and excellent overall ADME (absorption, distribution, metabolism, excretion) properties in multiple preclinical species, 33 was advanced into clinical trials, including an ongoing Phase 2 clinical trial in patients with lung fibrosis (NCT04308681).

Alleviation of Pseudomonas aeruginosa Infection by Propeptide-Mediated Inhibition of Protease IV

Pseudomonas aeruginosa, an opportunistic human pathogen, expresses protease IV (PIV) for infection. Since the PIV activity can be inhibited by its propeptide, we tried to alleviate the severity of P. aeruginosa infection using the purified PIV propeptide (PIV_pp). The PIV_pp treatment of P. aeruginosa could significantly inhibit the PIV activity and reduce the virulence of P. aeruginosa in multiple invertebrate infection models, such as nematodes, brine shrimp, and mealworms. The effectiveness of PIV_pp was further confirmed using mouse skin infection and acute/chronic lung infection models. The amount of PIV_pp that inhibited the PIV activity of P. aeruginosa by 65% could alleviate the severity of infection significantly in all of the skin and acute/chronic lung infections. In addition, the PIV_pp treatment of P. aeruginosa facilitated the healing of the skin wound infections and repressed the growth of P. aeruginosa in the infected lung. The PIV_pp itself did not cause the induction of inflammatory cytokines or have any harmful effects on host tissues and did not affect bacterial growth. Taken together, P. aeruginosa infections can be alleviated by PIV_pp treatment. IMPORTANCE Pseudomonas aeruginosa is a highly antibiotic-resistant pathogen and is extremely difficult to treat. Instead of using conventional antibiotics, we attempted to alleviate P. aeruginosa infection using factors that P. aeruginosa itself produces naturally. Extracellular proteases are powerful virulence factors and important targets to control the P. aeruginosa infections. Propeptides are originally expressed as part of extracellular proteases, inhibiting their activity until they go out of the cell, preventing them from becoming toxic to the cells themselves. We confirmed, from multiple animal experiments, that treating P. aeruginosa with the purified propeptide can alleviate its infectivity. Propeptides specifically inhibit only their cognate protease without inhibiting other essential proteases of the host. The development of resistance can be avoided because the propeptide-mediated inhibition is an inherent mechanism of P. aeruginosa; hence, it will be difficult for P. aeruginosa to alter this mechanism. Since propeptides do not affect bacterial growth, there is no selective pressure to develop resistant cells.

Nucleotide-Oligomerizing Domain-1 Activation Exaggerates Cigarette Smoke-Induced Chronic Obstructive Pulmonary-Like Disease in Mice

Introduction

Chronic obstructive pulmonary disease (COPD) is a progressive condition related to abnormal inflammatory responses. As an inflammatory driver, nucleotide-binding oligomerizing domain-1 (NOD1) is highly expressed in pulmonary inflammatory cells; however, the roles of NOD1 in COPD are unknown.

Methods

A COPD mouse model was established by lipopolysaccharides tracheal instillation plus cigarette smoke (CS) exposure. NOD1 activation was induced by C12-iE-DAP (iE) treatment in both control and COPD mice. Inflammatory infiltration, pulmonary histological damage and gene expression were measured to evaluate the lung function of treated mice.

Results

The results showed that NOD1 was up-regulated in COPD mice, which significantly exaggerated CS-induced impairment of lung function, demonstrated by increased airway resistance, functional residual capacity and pulmonary damages. Mechanistically, NOD1 activation strongly activated the TLR4/NF-κB signaling pathway and then increased inflammatory responses and promoted the secretion of inflammatory cytokines.

Discussion

This study demonstrates that NOD1 is an important risk factor in the progression of COPD; therefore, targeting NOD1 in lung tissues is a potential strategy for COPD treatment.

USP13-mediated IRAK4 deubiquitination disrupts the pathological symptoms of lipopolysaccharides-induced sepsis

Ubiquitin-specific peptidase 13 (USP13) has been reported to participate in tumorigenesis, cell cycle arrest, endoplasmic reticulum-associated degradation, and immune responses. Here, we explored the function of USP13 in pro-inflammatory cytokine production of macrophages and its role in mouse sepsis model. Primary bone-marrow-derived macrophages (BMDMs) isolated from wild type (WT) and USP13^MKO mice were treated by lipopolysaccharides (LPS), IL-4, toll-like receptors (TLRs) agonists, and IRAK4 inhibitor to profile the inflammatory responses with different genotypes. Mouse sepsis model (WT and USP13^MKO) created by intraperitoneal injection with LPS plus D-galactosamine was used to assess septic shock-induced survival and lung inflammation. Flow cytometry, qRT-PCT, Western blot, and ELISA were performed to detect pro-inflammatory production and macrophage polarization. USP13 was a key regulator of IRAK4 deubiquitination in BMDMs and its myeloid specific deficiency contributed to LPS-induced pro-inflammatory response and septic symptoms. IRAK4 inhibitor co-administration improved in LPS-induced inflammatory responses in both BMDMs and septic mice. USP13 negatively regulates LPS-induced sepsis shock by targeting IRAK4. In summary, targeting USP13-IRAK4 axis might be a potential therapeutic strategy for the treatment of inflammation in sepsis shock.

Intracellular lipid droplet accumulation occurs early following viral infection and is required for an efficient interferon response

Lipid droplets (LDs) are increasingly recognized as critical organelles in signalling events, transient protein sequestration and inter-organelle interactions. However, the role LDs play in antiviral innate immune pathways remains unknown. Here we demonstrate that induction of LDs occurs as early as 2 h post-viral infection, is transient and returns to basal levels by 72 h. This phenomenon occurs following viral infections, both in vitro and in vivo. Virally driven in vitro LD induction is type-I interferon (IFN) independent, and dependent on Epidermal Growth Factor Receptor (EGFR) engagement, offering an alternate mechanism of LD induction in comparison to our traditional understanding of their biogenesis. Additionally, LD induction corresponds with enhanced cellular type-I and -III IFN production in infected cells, with enhanced LD accumulation decreasing viral replication of both Herpes Simplex virus 1 (HSV-1) and Zika virus (ZIKV). Here, we demonstrate, that LDs play vital roles in facilitating the magnitude of the early antiviral immune response specifically through the enhanced modulation of IFN following viral infection, and control of viral replication. By identifying LDs as a critical signalling organelle, this data represents a paradigm shift in our understanding of the molecular mechanisms which coordinate an effective antiviral response.

First evidence of Klebsiella pneumoniae infection in Aceh cattle: Pathomorphology and antigenic distribution in the lungs

BACKGROUND AND AIM

Klebsiella pneumoniae is an emerging zoonotic and foodborne pathogen worldwide. Hypervirulent K. pneumoniae (hvKp) was reported as the causative agent of bovine mastitis. This is the first study in Indonesia that has been conducted to determine the capsular serotype of K. pneumoniae, pulmonary gross pathology and histopathology, and distribution of hvKp in the lungs of Aceh cattle.

MATERIALS AND METHODS

The presence of K. pneumoniae in Aceh cattle was investigated in two slaughterhouses in Banda Aceh and Aceh Besar, Indonesia. Lung tissues with gross pathological lesions were collected from 15 cattle presenting with depression, dehydration, or cachexia. The confirmation and capsular serotyping of K. pneumoniae isolates were performed using polymerase chain reaction. The tissues were stained with hematoxylin-eosin and immunohistochemistry to observe the histopathological lesions and the distribution of the hvKp antigens.

RESULTS

The pneumonic lesions identified in the lungs of Aceh cattle included hyperemia, hemorrhage, consolidation, and atelectasis. K. pneumoniae was isolated in all 15 lung tissues with pathological pneumonic lesions. Two patterns of infection were observed histopathologically. Acute infection was characterized by hyperemia, inflammatory cell infiltration, hemorrhage, bronchiolar epithelium hyperplasia, bronchial and bronchiolar obstruction with purulent exudates, edema, and atelectasis. On the other hand, chronic infection was defined by macrophage infiltration, emphysema, bronchial dilatation, pleural fibrosis, and alveolar wall thickening by interstitial fibrosis. Immunohistochemical staining using monospecific antisera induced by the hvKp isolate confirmed the presence of K. pneumoniae-specific antigens in the acute infection, predominantly in the bronchiolar, vascular, and alveolar areas. In contrast, generally diffuse infiltrates were found in the pleura and interstitial alveolar areas in chronic infection.

CONCLUSION

hvKp can be detected in the lungs of Aceh cattle, representing acute and chronic infections. The distribution of Klebsiella antigens in the lung tissue was consistent with the histopathological findings.

Studies on the safety and the tissue distribution of inhaled high-dose amorphous and crystalline rifampicin in a rat model

Inhaled delivery of rifampicin has the potential to achieve high drug concentrations in the lung and the blood for efficient treatment of tuberculosis (TB). Due to its existence as polymorphs, in vivo evaluation of the respiratory tract safety of inhalable amorphous and crystalline rifampicin particles, at clinically relevant high-dose, is necessary. This study investigates the lung and liver safety and the tissue distribution of rifampicin after intra-tracheal administration of high (≥25 mg/kg) doses of amorphous and crystalline powder formulations to Sprague Dawley rats. Powder formulations were administered by intra-tracheal insufflation to rats. Lung and liver safety were evaluated by histopathology. Serum alanine transaminase (ALT) and aspartate aminotransferase (AST) assays were performed to study the hepatic effects. Rifampicin was quantified in the tissues using LC-MS/MS. Intra-tracheal administration of rifampicin decreased the drug burden on the liver compared to oral administration based on its lower serum ALT activity. Repeated-dose intra-tracheal rifampicin was well tolerated by rats, confirmed by the absence of drug or delivery induced complexities. The histopathological evaluation of rat lungs, after both single and repeated drug administration for seven days, suggested the absence of drug-induced toxicity. Following single intra-tracheal delivery of 50 mg/kg doses, comparable rifampicin concentrations to that from same oral dose were observed in lung, liver, heart and brain. Inhaled delivery of high-dose rifampicin was safe to rat lungs and liver suggesting its potential for localized as well as systemic drug delivery without toxicity concerns.

Cardiolipin-mediated PPARγ S112 phosphorylation impairs IL-10 production and inflammation resolution during bacterial pneumonia

Bacterial pneumonia is a global healthcare burden, and unwarranted inflammation is suggested as an important cause of mortality. Optimum levels of the anti-inflammatory cytokine IL-10 are essential to reduce inflammation and improve survival in pneumonia. Elevated levels of the mitochondrial-DAMP cardiolipin (CL), reported in tracheal aspirates of pneumonia patients, have been shown to block IL-10 production from lung MDSCs. Although CL-mediated K107 SUMOylation of PPARγ has been suggested to impair this IL-10 production, the mechanism remains elusive. We identify PIAS2 to be the specific E3-SUMOligase responsible for this SUMOylation. Moreover, we identify a concomitant CL-mediated PPARγ S112 phosphorylation, mediated by JNK-MAPK, to be essential for PIAS2 recruitment. Furthermore, using a clinically tested peptide inhibitor targeting JNK-MAPK, we blocked these post-translational modifications (PTMs) of PPARγ and rescued IL-10 expression, improving survival in murine pneumonia models. Thus, we explore the mechanism of mito-DAMP-mediated impaired lung inflammation resolution and propose a therapeutic strategy targeting PPARγ PTMs.

Preventive Effects of Intrauterine Injection of Bone Marrow-Derived Mesenchymal Stromal Cell-Conditioned Media on Uterine Fibrosis Immediately after Endometrial Curettage in Rabbit

Uterine fibrosis is an acquired disorder leading to menstrual irregularities, implantation impairment, and abortion. Mesenchymal stromal cells (MSCs) have antifibrotic properties through chemokine secretion. MSC-conditioned media (MSC-CM) contain paracrine components—exosomes—with a great potential for repairing damaged tissue or preventing fibrosis. The main goal of this study was to evaluate the preventive effects of bone marrow-derived MSC-CM (BM-MSC-CM) on uterine fibrosis after uterine curettage in rabbits. This study included 12 female rabbits (24 uterine horns in total). Excised uteri of each of the 12 female rabbits were randomly divided into four groups of intact negative control, curettage positive control, BM-MSC injection, and BM-MSC-CM injection in the way that two corresponding uteri from a rabbit were allocated to different groups. The MSC-CM were collected from cultivated BM-MSCs 48 hours after having been washed three times and replaced in serum-free media. Through a surgical approach, the caudal parts of the uteri were submitted to traumatic endometrial curettage, except for the intact negative uteri. After suturing the uterine walls, BM-MSCs or BM-MSC-CM were injected in the curettage site. Endometrial regeneration was histologically evaluated 30 days after treatment. Based on the evaluation of histomorphometric indices, curettage with or without preventive injections increased the growth of endometrial layers. However, the amount of fibrotic tissue in the CM and the BM-MSC injection groups was the same as the normal control groups, and all were less than the curettage group. A single injection of CM of MSCs after 30 days prevented the fibrotic tissue formation induced by curettage in endometrial layers of rabbits. Injecting BM-MSC-CM immediately after curettage prevented and reduced the uterine fibrosis similar to BM-MSCs in a rabbit model.

Diosgenin inhibits TGF-β1/Smad signaling and regulates epithelial mesenchymal transition in experimental pulmonary fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a grave disease characterized by abnormal wound healing associated with chronic, progressive, irreversible fatal lung disease, leading to persistent injuries to the alveolar epithelium. A consequent disturbance of fibroblast proliferation and apoptosis results in subsequent release of pro-inflammatory and pro-fibrotic mediators coupled with accumulation of extracellular matrix within the interstitium. Inexorable distortion of lung alveolar architecture leads to respiratory failure with a median survival rate of 3-5 years. Currently available drugs can only slowdown the progression of fibrosis and novel drugs are warranted to treat this disease. In this study, we demonstrate the fibro-protective effect of diosgenin in experimental lung fibrosis through regulation of Epithelial Mesenchymal Transition (EMT). A single dose of 3 U/kg body weight (b.wt) Bleomycin (BLM) was administered intratracheally in Wistar male albino rats and fibrotic animals were treated with diosgenin (100 mg/kg b.wt) orally for 28 days. BLM administered rat show histological alteration with increased mast cell and collagen accumulation. BLM induced abnormalities were significantly reduced upon treatment with diosgenin. Western blot analysis revealed an increased level of pro-inflammatory and pro-fibrotic molecules such as IL-1β and TGF-β in BLM induced rats. Rats supplemented with diosgenin showed a decreased expression of inflammatory and pro-fibrotic mediators. Markers of EMT molecules were evaluated by immunoblot. The results of immunoblot demonstrate that diosgenin regulated the expression of TGF-β mediated EMT. Hence, from the overall study, administration of diosgenin prevents pulmonary fibrosis by restraint inflammation and EMT.

Intrapulmonary inoculation of multicellular spheroids to construct an orthotopic lung cancer xenograft model that mimics four clinical stages of non-small cell lung cancer

INTRODUCTION

Lung cancer leads in mortality among all types of cancer in US and Non-small cell lung cancer (NSCLC) is the major type of lung cancer. Mice models of lung cancer based on subcutaneous or orthotopic inoculation of cancer cell suspension do not adequately mimic the progression of lung cancer in clinic.

METHODS

A549-iRFP cells (human NSCLC adenocarcinoma) were cultured to form multicellular spheroids (MCS), which were then inoculated intrapulmonarily into male athymic nude mice. The xenograft cancer development was monitored by in vivo fluorescent imaging and validated by open-chest anatomy, ex vivo fluorescent imaging, and histological studies.

RESULTS

The newly developed orthotopic xenograft model of lung cancer simulated all four clinical stages of NSCLC progression over one month: Stage 1) localized tumor at the inoculation site, Stage 2) multiple tumor nodules or larger tumor nodule on the same side of the lung, Stage 3) cancer growth on heart surface, and Stage 4) metastatic cancer on both sides of the lung. The model yielded high rates of postoperative survival (100%) and parenchymal tumor establishment (88.9%). The roughness of the inoculated MCS associated negatively with the time needed to develop metastatic cancer (p = .0299).

DISCUSSION

This new orthotopic xenograft model of NSCLC would facilitate the development of medications to treat lung cancer.

Silica particles disorganize the polarization of pulmonary macrophages in mice

Silicosis is a fatal fibrotic lung disease caused by long-term silica particle exposure, in which pulmonary macrophages play an important role. However, the relationship between macrophage polarization and silicosis remains unclear. We established an experimental silicosis mouse model to investigate macrophage polarization during silicosis development. C57BL/c mice were exposed to silica by intra-tracheal instillation and sacrificed at different time points. Lung tissues and bronchoalveolar lavage fluid were collected for flow cytometry, quantitative reverse transcription polymerase chain reaction, enzyme-linked immunosorbent assays, western blotting, and histology examinations. The polarization of pulmonary macrophages was dysregulated during silicosis development. In the early stage of silicosis, M1 macrophages were induced and played a leading role in eliciting inflammatory; in the late stage, M2 macrophages were induced to promote tissue repair. Levels of several cytokines in lung tissue microenvironment changed with macrophage polarization. Inflammatory cytokines such as tumor necrosis factor-α and interleukin (IL)-1β and IL-6 were upregulated in the inflammation stage, while the anti-inflammatory cytokine IL-10 was upregulated in the fibrosis stage. Furthermore, we found that STAT (signal transducer and activator of transcription) and IRF (interferon regulatory factor) signaling pathway were involved in the regulation of macrophage polarization in silicosis. In summary, macrophage polarization is closely related to the occurrence and development of silicosis and may be a key point for further elucidating silicosis pathogenesis.

Stem cell transplantation impairs dendritic cell trafficking and herpesvirus immunity

Long-term survivors after hematopoietic stem cell transplantation are at high risk of infection, which accounts for one-third of all deaths related to stem cell transplantation. Little is known about the cause of inferior host defense after immune cell reconstitution. Here, we exploited a murine syngeneic BM transplantation (BMT) model of late infection with murine gammaherpesvirus 68 (MHV-68) to determine the role of conventional DC (cDC) trafficking in adaptive immunity in BMT mice. After infection, the expression of chemokine Ccl21 in the lung is reduced and the migration of cDCs into lung draining lymph nodes (dLNs) is impaired in BMT mice, limiting the opportunity for cDCs to prime Th cells in the dLNs. While cDC subsets are redundant in priming Th1 cells, Notch2 functions in cDC2s are required for priming increased Th17 responses in BMT mice, and cDC1s can lessen this activity. Importantly, Th17 cells can be primed both in the lungs and dLNs, allowing for increased Th17 responses without optimum cDC trafficking in BMT mice. Taken together, impaired cDC trafficking in BMT mice reduces protective Th1 responses and allows increased pathogenic Th17 responses. Thus, we have revealed a previously unknown mechanism for BMT procedures to cause long-term inferior immune responses to herpes viral infection.

Capturing the multifactorial nature of ARDS - "Two-hit" approach to model murine acute lung injury

Severe acute respiratory distress syndrome (ARDS) presents typically with an initializing event, followed by the need for mechanical ventilation. Most animal models of ALI are limited by the fact that they focus on a singular cause of acute lung injury (ALI) and therefore fail to mimic the complex, multifactorial pathobiology of ARDS. To better capture this scenario, we provide a comprehensive characterization of models of ALI combining two injuries: intra tracheal (i.t.) instillation of LPS or hypochloric acid (HCl) followed by ventilator‐induced lung injury (VILI). We hypothesized, that mice pretreated with LPS or HCl prior to VILI and thus receiving a (“two‐hit injury”) will sustain a superadditive lung injury when compared to VILI. Mice were allocated to following treatment groups: control with i.t. NaCl, ventilation with low peak inspiratory pressure (PIP), i.t. HCl, i.t. LPS, VILI (high PIP), HCl i.t. followed by VILI and LPS i.t. followed by VILI. Severity of injury was determined by protein content and MPO activity in bronchoalveolar lavage (BAL), the expression of inflammatory cytokines and histopathology. Mice subjected to VILI after HCl or LPS instillation displayed augmented lung injury, compared to singular lung injury. However, mice that received i.t. LPS prior to VILI showed significantly increased inflammatory lung injury compared to animals that underwent i.t. HCl followed by VILI. The two‐hit lung injury models described, resulting in additive but differential acute lung injury recaptures the clinical relevant multifactorial etiology of ALI and could be a valuable tool in translational research.