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Baldassi D, Ngo TMH, Merkel OM. Optimization of Lung Surfactant Coating of siRNA Polyplexes for Pulmonary Delivery. Pharm Res 2024; 41:77-91. [PMID: 36447020 PMCID: PMC9708138 DOI: 10.1007/s11095-022-03443-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 11/18/2022] [Indexed: 12/05/2022]
Abstract
PURPOSE The aim of this study was to understand how coating with a pulmonary surfactant, namely Alveofact, affects the physicochemical parameters as well as in vitro behavior of polyethylenimine (PEI) polyplexes for pulmonary siRNA delivery. METHODS Alveofact-coated polyplexes were prepared at different Alveofact:PEI coating ratios and analyzed in terms of size, PDI and zeta potential as well as morphology by transmission electron microscopy. The biological behavior was evaluated in a lung epithelial cell line regarding cell viability, cellular uptake via flow cytometry and gene downregulation by qRT-PCR. Furthermore, a 3D ALI culture model was established to test the mucus diffusion and cellular uptake by confocal microscopy as well as gene silencing activity by qRT-PCR. RESULTS After optimizing the coating process by testing different Alveofact:PEI coating ratios, a formulation with suitable parameters for lung delivery was obtained. In lung epithelial cells, Alveofact-coated polyplexes were well tolerated and internalized. Furthermore, the coating improved the siRNA-mediated gene silencing efficiency. Alveofact-coated polyplexes were then tested on a 3D air-liquid interface (ALI) culture model that, by expressing tight junctions and secreting mucus, resembles important traits of the lung epithelium. Here, we identified the optimal Alveofact:PEI coating ratio to achieve diffusion through the mucus layer while retaining gene silencing activity. Interestingly, the latter underlined the importance of establishing appropriate in vitro models to achieve more consistent results that better predict the in vivo activity. CONCLUSION The addition of a coating with pulmonary surfactant to polymeric cationic polyplexes represents a valuable formulation strategy to improve local delivery of siRNA to the lungs.
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Affiliation(s)
- Domizia Baldassi
- Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig-Maximilians University of Munich, Butenandtstraße 5, 81377, Munich, Germany
| | - Thi My Hanh Ngo
- Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig-Maximilians University of Munich, Butenandtstraße 5, 81377, Munich, Germany
| | - Olivia M Merkel
- Department of Pharmacy, Pharmaceutical Technology and Biopharmaceutics, Ludwig-Maximilians University of Munich, Butenandtstraße 5, 81377, Munich, Germany.
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Müller H, Schmiedl A, Weiss C, Ai M, Jung S, Renner M. DMBT1 is upregulated in lung epithelial cells after hypoxia and changes surfactant ultrastructure. Pediatr Pulmonol 2020; 55:2964-2969. [PMID: 32770804 DOI: 10.1002/ppul.25018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 08/05/2020] [Indexed: 11/11/2022]
Abstract
BACKGROUND Hypoxia and asphyxia are known to induce surfactant inactivation in newborns. Deleted in Malignant Brain Tumors 1 (DMBT1) is an innate immunity protein with functions in epithelial differentiation and angiogenesis. It was detected in hyaline membranes of infants with respiratory distress syndrome. Human recombinant DMBT1 is able to increase the surface tension of exogenous surfactant preparations in a dose-dependent manner. METHODS Immunohistochemistry was performed on lung sections of infants who died due to pre-, peri- or postnatal hypoxia. The lung epithelial cell line A549 was stably transfected with a DMBT1 (DMBT1+ cells) expression plasmid or with an empty plasmid (DMBT1- cells). The cells were cultured in normoxic or hypoxic conditions, and then DMBT1 as well as HIF-1α RNA expression were analyzed by using real-time-polymerase chain reaction. Human recombinant DMBT1 was added to the modified porcine natural surfactant Curosurf to examine the effect of DMBT1 on surfactant ultrastructure with electron microscopy. RESULTS DMBT1 expression was upregulated in human lung tissue after fetal/peri-/postnatal hypoxia. In addition, in vitro experiments showed increased DMBT1 RNA expression in A549 cells after hypoxia. HIF-1α was upregulated in both DMBT1+ and DMBT1- cells in response to hypoxia. The addition of human recombinant DMBT1 to Curosurf caused an impaired surfactant ultrastructure. CONCLUSIONS DMBT1 is upregulated in response to hypoxia and there seems to be a link between hypoxia and surfactant inactivation.
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Affiliation(s)
- Hanna Müller
- Division of Neonatology and Pediatric Intensive Care, Department of Pediatrics, University Hospital Erlangen, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Andreas Schmiedl
- Institute of Functional and Applied Anatomy, Hannover Medical School, Hannover, Germany
| | - Christel Weiss
- Department for Medical Statistics and Biomathematics, University Hospital Mannheim, Mannheim, Germany
| | - Maria Ai
- Division of Neonatology and Pediatric Intensive Care, Department of Pediatrics, University Hospital Erlangen, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Susan Jung
- Department of Pediatrics, University Hospital Erlangen, University of Erlangen-Nürnberg, Erlangen, Germany
| | - Marcus Renner
- Institute of Pathology, University of Heidelberg, Heidelberg, Germany
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Jörger A, Acevedo C, Busley D, Ganter M, Schmiedl A, Humann-Ziehank E. Stereological and biophysical characteristics of the ovine surfactant system and its changes caused by ovine pulmonary adenocarcinoma. Res Vet Sci 2017. [DOI: 10.1016/j.rvsc.2017.06.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Busley D, Ochs M, Hoeltig D, Ganter M, Acevedo C, Schmiedl A, Hennig-Pauka I. Characterization of surfactant alterations in pigs infected withActinobacillus pleuropneumoniae. Exp Lung Res 2016; 42:1-13. [DOI: 10.3109/01902148.2015.1123327] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Ledford JG, Addison KJ, Foster MW, Que LG. Eosinophil-associated lung diseases. A cry for surfactant proteins A and D help? Am J Respir Cell Mol Biol 2015; 51:604-14. [PMID: 24960334 DOI: 10.1165/rcmb.2014-0095tr] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Surfactant proteins (SP)-A and SP-D (SP-A/-D) play important roles in numerous eosinophil-dominated diseases, including asthma, allergic bronchopulmonary aspergillosis, and allergic rhinitis. In these settings, SP-A/-D have been shown to modulate eosinophil chemotaxis, inhibit eosinophil mediator release, and mediate macrophage clearance of apoptotic eosinophils. Dysregulation of SP-A/-D function in eosinophil-dominated diseases is also not uncommon. Alterations in serum SP-A/-D levels are associated with disease severity in allergic rhinitis and chronic obstructive pulmonary disease. Furthermore, oligimerization of SP-A/-D, necessary for their proper function, can be perturbed by reactive nitrogen species, which are increased in eosinophilic disease. In this review, we highlight the associations of eosinophilic lung diseases with SP-A and SP-D levels and functions.
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Affiliation(s)
- Julie G Ledford
- 1 Department of Medicine, Division of Pulmonary, Allergy and Critical Care, and
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Zasadzinski JA, Stenger PC, Shieh I, Dhar P. Overcoming rapid inactivation of lung surfactant: analogies between competitive adsorption and colloid stability. BIOCHIMICA ET BIOPHYSICA ACTA 2010; 1798:801-28. [PMID: 20026298 PMCID: PMC2834873 DOI: 10.1016/j.bbamem.2009.12.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2009] [Revised: 12/13/2009] [Accepted: 12/15/2009] [Indexed: 01/05/2023]
Abstract
Lung surfactant (LS) is a mixture of lipids and proteins that line the alveolar air-liquid interface, lowering the interfacial tension to levels that make breathing possible. In acute respiratory distress syndrome (ARDS), inactivation of LS is believed to play an important role in the development and severity of the disease. This review examines the competitive adsorption of LS and surface-active contaminants, such as serum proteins, present in the alveolar fluids of ARDS patients, and how this competitive adsorption can cause normal amounts of otherwise normal LS to be ineffective in lowering the interfacial tension. LS and serum proteins compete for the air-water interface when both are present in solution either in the alveolar fluids or in a Langmuir trough. Equilibrium favors LS as it has the lower equilibrium surface pressure, but the smaller proteins are kinetically favored over multi-micron LS bilayer aggregates by faster diffusion. If albumin reaches the interface, it creates an energy barrier to subsequent LS adsorption that slows or prevents the adsorption of the necessary amounts of LS required to lower surface tension. This process can be understood in terms of classic colloid stability theory in which an energy barrier to diffusion stabilizes colloidal suspensions against aggregation. This analogy provides qualitative and quantitative predictions regarding the origin of surfactant inactivation. An important corollary is that any additive that promotes colloid coagulation, such as increased electrolyte concentration, multivalent ions, hydrophilic non-adsorbing polymers such as PEG, dextran, etc. added to LS, or polyelectrolytes such as chitosan, also promotes LS adsorption in the presence of serum proteins and helps reverse surfactant inactivation. The theory provides quantitative tools to determine the optimal concentration of these additives and suggests that multiple additives may have a synergistic effect. A variety of physical and chemical techniques including isotherms, fluorescence microscopy, electron microscopy and X-ray diffraction show that LS adsorption is enhanced by this mechanism without substantially altering the structure or properties of the LS monolayer.
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Affiliation(s)
- Joseph A Zasadzinski
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA.
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Sato A, Whitsett JA, Scheule RK, Ikegami M. Surfactant protein-d inhibits lung inflammation caused by ventilation in premature newborn lambs. Am J Respir Crit Care Med 2010; 181:1098-105. [PMID: 20133924 DOI: 10.1164/rccm.200912-1818oc] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
RATIONALE Premature newborns frequently require manual ventilation for resuscitation during which lung injury occurs. Although surfactant protein (SP)-D regulates pulmonary inflammation, SP-D levels are low in the preterm lung. Commercial surfactants for treatment of respiratory distress syndrome do not contain SP-D. OBJECTIVES To determine whether addition of recombinant human SP-D (rhSP-D) to commercial surfactant influences lung inflammation in ventilated premature newborn lambs. METHODS Prematurely delivered lambs (130 d gestation age) were resuscitated with 100% O(2) and peak inspiratory pressure 40 cm H(2)O for 20 minutes and then treated with Survanta or Survanta containing rhSP-D. Ventilation was then changed to regulate tidal volume at 8 to 9 ml/kg. At 5 hours of age lambs were killed for sample collection. MEASUREMENTS AND MAIN RESULTS Sequential blood gas and tidal volume were similar in lambs treated with or without rhSP-D, indicating that lung immaturity and ventilatory stress used to support premature lambs were comparable between the two groups. Ventilation caused pulmonary inflammation in lambs treated with surfactant alone. In contrast, surfactant containing rhSP-D decreased neutrophil numbers in bronchoalveolar lavage fluid and decreased neutrophil elastase activity in lung tissue. IL-8 mRNA and IL-8 protein were significantly decreased in the +rhSP-D group lamb lungs, to 20% of those in controls. The addition of rhSP-D also rendered Survanta more resistant to plasma protein inhibition of surfactant function. CONCLUSIONS Treatment with rhSP-D-containing surfactant inhibited lung inflammation and enhanced the resistance of surfactant to inhibition, supporting its potential usefulness for prevention of lung injury in the preterm newborn.
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Affiliation(s)
- Atsuyasu Sato
- Cincinnati Children's Hospital Medical Center, Division of Pulmonary Biology, 3333 Burnet Avenue, Cincinnati, OH 45229-3039, USA
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Chen HL, Hai CX, Liang X, Zhang XD, Liu R, Qin XJ. Correlation between sPLA2-IIA and phosgene-induced rat acute lung injury. Inhal Toxicol 2009; 21:374-80. [PMID: 19235614 DOI: 10.1080/08958370802449712] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Secreted phospholipase A(2) of group IIA (sPLA(2)-IIA) has been involved in a variety of inflammatory diseases, including acute lung injury. However, the specific role of sPLA(2)-IIA in phosgene-induced acute lung injury remains unidentified. The aim of the present study was to investigate the correlation between sPLA(2)-IIA activity and the severity of phosgene-induced acute lung injury. Adult male rats were randomly exposed to either normal room air (control group) or a concentration of 400 ppm phosgene (phosgene-exposed group) for there are 5 phosgene-exposed groups altogether. For the time points of 1, 3, 6, 12 and 24 h post-exposure, one phosgene-exposed group was sacrificed at each time point. The severity of acute lung injury was assessed by Pa(O2)/F(IO2) ratio, wet-to-dry lung-weight ratio, and bronchoalveolar lavage (BAL) fluid protein concentration. sPLA(2)-IIA activity in BAL fluid markedly increased between 1 h and 12 h after phosgene exposure, and reached its highest level at 6 h. Moreover, the trend of this elevation correlated well with the severity of lung injury. These results indicate that sPLA(2)-IIA probably participates in phosgene-induced acute lung injury.
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Affiliation(s)
- Hong-li Chen
- Department of Toxicology, Fourth Military Medical University, Xi'an, China
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Mühlfeld C, Liakopoulos OJ, Schaefer IM, Schöndube FA, Richter J, Dörge H. Methylprednisolone Fails to Preserve Pulmonary Surfactant and Blood–Air Barrier Integrity in a Porcine Cardiopulmonary Bypass Model. J Surg Res 2008; 146:57-65. [PMID: 17583746 DOI: 10.1016/j.jss.2007.03.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 03/01/2007] [Accepted: 03/13/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND Pulmonary inflammation after cardiac surgery with cardiopulmonary bypass (CPB) has been linked to respiratory dysfunction and ultrastructural injury. Whether pretreatment with methylprednisolone (MP) can preserve pulmonary surfactant and blood-air barrier, thereby improving pulmonary function, was tested in a porcine CPB-model. MATERIALS AND METHODS After randomizing pigs to placebo (PLA; n = 5) or MP (30 mg/kg, MP; n = 5), animals were subjected to 3 h of CPB with 1 h of cardioplegic cardiac arrest. Hemodynamic data, plasma tumor necrosis factor-alpha (TNF-alpha, ELISA), and pulmonary function parameters were assessed before, 15 min after CPB, and 8 h after CPB. Lung biopsies were analyzed for TNF-alpha (Western blot) or blood-air barrier and surfactant morphology (electron microscopy, stereology). RESULTS Systemic TNF-alpha increased and cardiac index decreased at 8 h after CPB in PLA (P < 0.05 versus pre-CPB), but not in MP (P < 0.05 versus PLA). In both groups, at 8 h after CPB, PaO2 and PaO2/FiO2 were decreased and arterio-alveolar oxygen difference and pulmonary vascular resistance were increased (P < 0.05 versus baseline). Postoperative pulmonary TNF-alpha remained unchanged in both groups, but tended to be higher in PLA (P = 0.06 versus MP). The volume fraction of inactivated intra-alveolar surfactant was increased in PLA (58 +/- 17% versus 83 +/- 6%) and MP (55 +/- 18% versus 80 +/- 17%) after CPB (P < 0.05 versus baseline for both groups). Profound blood-air barrier injury was present in both groups at 8 h as indicated by an increased blood-air barrier integrity score (PLA: 1.28 +/- 0.03 versus 1.70 +/- 0.1; MP: 1.27 +/- 0.08 versus 1.81 +/- 0.1; P < 0.05). CONCLUSION Despite reduction of the systemic inflammatory response and pulmonary TNF-alpha generation, methylprednisolone fails to decrease pulmonary TNF-alpha and to preserve pulmonary surfactant morphology, blood-air barrier integrity, and pulmonary function after CPB.
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Affiliation(s)
- Christian Mühlfeld
- Department of Anatomy, Division of Electron Microscopy, University of Göttingen, Göttingen, Germany.
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Elastase-induced lung emphysema in rats is not reduced by hematopoietic growth factors when applied preventionally. Virchows Arch 2008; 452:675-88. [DOI: 10.1007/s00428-008-0591-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 01/07/2008] [Accepted: 01/27/2008] [Indexed: 11/30/2022]
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Braun A, Stenger PC, Warriner HE, Zasadzinski JA, Lu KW, Taeusch HW. A freeze-fracture transmission electron microscopy and small angle x-ray diffraction study of the effects of albumin, serum, and polymers on clinical lung surfactant microstructure. Biophys J 2007; 93:123-39. [PMID: 17416614 PMCID: PMC1914435 DOI: 10.1529/biophysj.106.095513] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Freeze-fracture transmission electron microscopy shows significant differences in the bilayer organization and fraction of water within the bilayer aggregates of clinical lung surfactants, which increases from Survanta to Curosurf to Infasurf. Albumin and serum inactivate all three clinical surfactants in vitro; addition of the nonionic polymers polyethylene glycol, dextran, or hyaluronic acid also reduces inactivation in all three. Freeze-fracture transmission electron microscopy shows that polyethylene glycol, hyaluronic acid, and albumin do not adsorb to the surfactant aggregates, nor do these macromolecules penetrate the interior water compartments of the surfactant aggregates. This results in an osmotic pressure difference that dehydrates the bilayer aggregates, causing a decrease in the bilayer spacing as shown by small angle x-ray scattering and an increase in the ordering of the bilayers as shown by freeze-fracture electron microscopy. Small angle x-ray diffraction shows that the relationship between the bilayer spacing and the imposed osmotic pressure for Curosurf is a screened electrostatic interaction with a Debye length consistent with the ionic strength of the solution. The variation in surface tension due to surfactant adsorption measured by the pulsating bubble method shows that the extent of surfactant aggregate reorganization does not correlate with the maximum or minimum surface tension achieved with or without serum in the subphase. Albumin, polymers, and their mixtures alter the surfactant aggregate microstructure in the same manner; hence, neither inhibition reversal due to added polymer nor inactivation due to albumin is caused by alterations in surfactant microstructure.
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Affiliation(s)
- Andreas Braun
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106, USA
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Ochs M, Schüttler M, Stichtenoth G, Herting E. Morphological alterations of exogenous surfactant inhibited by meconium can be prevented by dextran. Respir Res 2006; 7:86. [PMID: 16756655 PMCID: PMC1489943 DOI: 10.1186/1465-9921-7-86] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Accepted: 06/06/2006] [Indexed: 02/07/2023] Open
Abstract
Background Surfactant dysfunction due to inhibition is involved in the pathophysiology of meconium aspiration syndrome. Dextran addition has been shown to reverse exogenous surfactant inactivation by meconium, but the precise mechanisms and the morphological correlate of this effect are yet unknown. Morphological surfactant analysis by transmission electron microscopy (TEM) and stereology allows the differentiation of active (large aggregates = LA) and inactive (small aggregates = SA) subtypes. Methods To determine the in vitro effects of meconium and dextran addition on the morphology of a modified porcine natural surfactant (Curosurf), Curosurf samples were either incubated alone or together with meconium or with meconium and dextran, fixed and processed for TEM. Volume fractions of surfactant subtypes [lamellar body-like forms (LBL), multilamellar vesicles (MV), unilamellar vesicles (UV)] were determined stereologically. Results All preparations contained LBL and MV (corresponding to LA) as well as UV (corresponding to SA). The volume fraction of UV increased with addition of meconium and decreased with further addition of dextran. Correspondingly, the UV/(LBL+MV) ratio (resembling the SA/LA ratio) increased when meconium was added and decreased when dextran was added to the surfactant-meconium mixture. Conclusion Meconium causes alterations in the ultrastructural composition of Curosurf that can be visualized and analyzed by TEM and stereology. These alterations resemble an increase in the SA/LA ratio and are paralleled by an increase in minimum surface tension. Dextran prevents these effects and may therefore be a useful additive to exogenous surfactant preparations to preserve their structural and functional integrity, thereby improving their resistance to inactivation.
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Affiliation(s)
- Matthias Ochs
- Institute of Anatomy, Experimental Morphology, University of Bern, Baltzerstrasse 2, CH-3012 Bern, Switzerland
- Department of Anatomy, Division of Electron Microscopy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany
| | - Markus Schüttler
- Department of Anatomy, Division of Electron Microscopy, University of Göttingen, Kreuzbergring 36, D-37075 Göttingen, Germany
| | - Guido Stichtenoth
- Department of Pediatrics, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
| | - Egbert Herting
- Department of Pediatrics, University of Lübeck, Ratzeburger Allee 160, D-23538 Lübeck, Germany
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