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Investigating how amine structure influences drug-amine ion-pair formation and uptake via the polyamine transporter in A549 lung cells

Mohamed Sofian Z, Harun N, Mahat MM, Nor Hashim NA, Jones SA

Eur J Pharm Biopharm, 2021 Nov;168:53-61.
PMID: 34455038 DOI: 10.1016/j.ejpb.2021.08.003

Transiently associating amines with therapeutic agents through the formation of ion-pairs has been established both in vitro and in vivo as an effective means to systemically direct drug delivery to the lung via the polyamine transport system (PTS). However, there remains a need to better understand the structural traits required for effective PTS uptake of drug ion-pairs. This study aimed to use a structurally related series of amine counterions to investigate how they influenced the stability of theophylline ion-pairs and their active uptake in A549 cells. Using ethylamine (mono-amine), ethylenediamine (di-amine), spermidine (tri-amine) and spermine (tetra-amine) as counterions the ion-pair affinity was shown to increase as the number of protonated amine groups in the counterion structure increased. The mono and diamines generated a single hydrogen bond and the weakest ion-pair affinities (pKFTIR: 1.32 ± 0.04 and 1.43 ± 0.02) whereas the polyamines produced two hydrogen bonds and thus the strongest ion-pair affinities (pKFTIR: 1.93 ± 0.05 and 1.96 ± 0.04). In A549 cells depleted of endogenous polyamines using α-difluoromethylornithine (DFMO), the spermine-theophylline uptake was significantly increased (p

Matched MeSH terms: Lung/cytology
In vitro cytotoxicity testing on valued added hydroxyapatite as bone replacement material

Shaari R, Samsudin AR

Med J Malaysia, 2004 May;59 Suppl B:109-10.
PMID: 15468842

The present in vitro evaluation indicated that the value added hydroxyapatite (HA) was more toxic than pure HA but the toxicity of value added HA was slight compared to the positive control. In this testing, the conclusion can be made that value added HA is less biocompatible than commercialized pure HA. This toxicity may be caused by both the particle size and degradation (leaching). Further studies should be carried out to determine whether there is particle size effect or leaching effect when using powder as compared to the block materials. The in vivo evaluation should be done to assess the reaction to this value added HA as compared to the pure HA.

Matched MeSH terms: Lung/cytology
Fulltext Understanding cellular mechanisms underlying airway epithelial repair: selecting the most appropriate animal models

Yahaya B

ScientificWorldJournal, 2012;2012:961684.
PMID: 23049478 DOI: 10.1100/2012/961684

Understanding the mechanisms underlying the process of regeneration and repair of airway epithelial structures demands close characterization of the associated cellular and molecular events. The choice of an animal model system to study these processes and the role of lung stem cells is debatable since ideally the chosen animal model should offer a valid comparison with the human lung. Species differences may include the complex three-dimensional lung structures, cellular composition of the lung airway as well as transcriptional control of the molecular events in response to airway epithelium regeneration, and repair following injury. In this paper, we discuss issues related to the study of the lung repair and regeneration including the role of putative stem cells in small- and large-animal models. At the end of this paper, the author discuss the potential for using sheep as a model which can help bridge the gap between small-animal model systems and humans.

Matched MeSH terms: Lung/cytology
Fulltext Antimycobacterial, antimicrobial, and biocompatibility properties of para-aminosalicylic acid with zinc layered hydroxide and Zn/Al layered double hydroxide nanocomposites

Saifullah B, El Zowalaty ME, Arulselvan P, Fakurazi S, Webster TJ, Geilich BM, et al.

Drug Des Devel Ther, 2014;8:1029-36.
PMID: 25114509 DOI: 10.2147/DDDT.S63753

The treatment of tuberculosis by chemotherapy is complicated due to multiple drug prescriptions, long treatment duration, and adverse side effects. We report here for the first time an in vitro therapeutic effect of nanocomposites based on para-aminosalicylic acid with zinc layered hydroxide (PAS-ZLH) and zinc-aluminum layered double hydroxides (PAS-Zn/Al LDH), against mycobacteria, Gram-positive bacteria, and Gram-negative bacteria. The nanocomposites demonstrated good antimycobacterial activity and were found to be effective in killing Gram-positive and Gram-negative bacteria. A biocompatibility study revealed good biocompatibility of the PAS-ZLH nanocomposites against normal human MRC-5 lung cells. The para-aminosalicylic acid loading was quantified with high-performance liquid chromatography analysis. In summary, the present preliminary in vitro studies are highly encouraging for further in vivo studies of PAS-ZLH and PAS-Zn/Al LDH nanocomposites to treat tuberculosis.

Matched MeSH terms: Lung/cytology
Metabolic glycan labeling and chemoselective functionalization of native biomaterials

Ren X, Evangelista-Leite D, Wu T, Rajab TK, Moser PT, Kitano K, et al.

Biomaterials, 2018 11;182:127-134.
PMID: 30118980 DOI: 10.1016/j.biomaterials.2018.08.012

Decellularized native extracellular matrix (ECM) biomaterials are widely used in tissue engineering and have reached clinical application as biomesh implants. To enhance their regenerative properties and postimplantation performance, ECM biomaterials could be functionalized via immobilization of bioactive molecules. To facilitate ECM functionalization, we developed a metabolic glycan labeling approach using physiologic pathways to covalently incorporate click-reactive azide ligands into the native ECM of a wide variety of rodent tissues and organs in vivo, and into the ECM of isolated rodent and porcine lungs cultured ex vivo. The incorporated azides within the ECM were preserved after decellularization and served as chemoselective ligands for subsequent bioconjugation via click chemistry. As proof of principle, we generated alkyne-modified heparin, immobilized it onto azide-incorporated acellular lungs, and demonstrated its bioactivity by Antithrombin III immobilization and Factor Xa inhibition. The herein reported metabolic glycan labeling approach represents a novel platform technology for manufacturing click-reactive native ECM biomaterials, thereby enabling efficient and chemoselective functionalization of these materials to facilitate tissue regeneration and repair.

Matched MeSH terms: Lung/cytology
Dengue virus regulates type I interferon signalling in a strain-dependent manner in human cell lines

Umareddy I, Tang KF, Vasudevan SG, Devi S, Hibberd ML, Gu F

J Gen Virol, 2008 Dec;89(Pt 12):3052-3062.
PMID: 19008393 DOI: 10.1099/vir.0.2008/001594-0

Outbreaks of dengue disease are constant threats to tropical and subtropical populations but range widely in severity, from mild to haemorrhagic fevers, for reasons that are still elusive. We investigated the interferon (IFN) response in infected human cell lines A549 and HepG2, using two strains (NGC and TSV01) of dengue serotype 2 (DEN2) and found that the two viruses exhibited a marked difference in inducing type I IFN response. While TSV01 infection led to activation of type I antiviral genes such as EIF2AK2 (PKR), OAS, ADAR and MX, these responses were absent in NGC-infected cells. Biochemical analysis revealed that NGC but not TSV01 suppressed STAT-1 and STAT-2 activation in response to type I IFN (alpha and beta). However, these two strains did not differ in their response to type II IFN (gamma). Although unable to suppress IFN signalling, TSV01 infection caused a weaker IFN-beta induction compared with NGC, suggesting an alternative mechanism of innate immune escape. We extended our study to clinical isolates of various serotypes and found that while MY10245 (DEN2) and MY22713 (DEN4) could suppress the IFN response in a similar fashion to NGC, three other strains of dengue [EDEN167 (DEN1), MY02569 (DEN1) and MY10340 (DEN2)] were unable to suppress the IFN response, suggesting that this difference is strain-dependent but not serotype-specific. Our report indicates the existence of a strain-specific virulence factor that may impact on disease severity.

Matched MeSH terms: Lung/cytology
Fulltext Identifying Early Target Cells of Nipah Virus Infection in Syrian Hamsters

Baseler L, Scott DP, Saturday G, Horne E, Rosenke R, Thomas T, et al.

PLoS Negl Trop Dis, 2016 Nov;10(11):e0005120.
PMID: 27812087 DOI: 10.1371/journal.pntd.0005120

BACKGROUND: Nipah virus causes respiratory and neurologic disease with case fatality rates up to 100% in individual outbreaks. End stage lesions have been described in the respiratory and nervous systems, vasculature and often lymphoid organs in fatal human cases; however, the initial target organs of Nipah virus infection have not been identified. Here, we detected the initial target tissues and cells of Nipah virus and tracked virus dissemination during the early phase of infection in Syrian hamsters inoculated with a Nipah virus isolate from Malaysia (NiV-M) or Bangladesh (NiV-B).
METHODOLOGY/PRINCIPAL FINDINGS: Syrian hamsters were euthanized between 4 and 48 hours post intranasal inoculation and tissues were collected and analyzed for the presence of viral RNA, viral antigen and infectious virus. Virus replication was first detected at 8 hours post inoculation (hpi). Nipah virus initially targeted type I pneumocytes, bronchiolar respiratory epithelium and alveolar macrophages in the lung and respiratory and olfactory epithelium lining the nasal turbinates. By 16 hpi, virus disseminated to epithelial cells lining the larynx and trachea. Although the pattern of viral dissemination was similar for both virus isolates, the rate of spread was slower for NiV-B. Infectious virus was not detected in the nervous system or blood and widespread vascular infection and lesions within lymphoid organs were not observed, even at 48 hpi.
CONCLUSIONS/SIGNIFICANCE: Nipah virus initially targets the respiratory system. Virus replication in the brain and infection of blood vessels in non-respiratory tissues does not occur during the early phase of infection. However, virus replicates early in olfactory epithelium and may serve as the first step towards nervous system dissemination, suggesting that development of vaccines that block virus dissemination or treatments that can access the brain and spinal cord and directly inhibit virus replication may be necessary for preventing central nervous system pathology.

Matched MeSH terms: Lung/cytology
Acanthamoebicidal activity of periglaucine A and betulinic acid from Pericampylus glaucus (Lam.) Merr. in vitro

Mahboob T, Azlan AM, Shipton FN, Boonroumkaew P, Nor Azman NS, Sekaran SD, et al.

Exp Parasitol, 2017 Dec;183:160-166.
PMID: 28916456 DOI: 10.1016/j.exppara.2017.09.002

Acanthamoeba species are pathogenic protozoa which account for amoebic keratitis, conjunctivitis and granulomatous amoebic encephalitis. These amoebae form cysts which resist drugs and more effective acanthamoebicidal agents are needed. Medicinal plants could be useful in improving the current treatment strategies for Acanthamoeba infections. In the present study, we examined the amoebicidal effects of Pericampylus glaucus (Lam.) Merr., a medicinal plant used for the treatment of conjunctivitis in Malaysia. Pathogenic Acanthamoeba triangularis were isolated from environmental water samples and treated with different concentrations of fractions obtained from Pericampylus glaucus (Lam.) Merr. as well as main constituents for 24-72 h. Chlorhexidine was used as a reference drug. Ethanol fraction of stem showed significant (p

Matched MeSH terms: Lung/cytology
Metformin synergizes 5-fluorouracil, epirubicin, and cyclophosphamide (FEC) combination therapy through impairing intracellular ATP production and DNA repair in breast cancer stem cells

Soo JS, Ng CH, Tan SH, Malik RA, Teh YC, Tan BS, et al.

Apoptosis, 2015 Oct;20(10):1373-87.
PMID: 26276035 DOI: 10.1007/s10495-015-1158-5

Metformin, an AMPK activator, has been reported to improve pathological response to chemotherapy in diabetic breast cancer patients. To date, its mechanism of action in cancer, especially in cancer stem cells (CSCs) have not been fully elucidated. In this study, we demonstrated that metformin, but not other AMPK activators (e.g. AICAR and A-769662), synergizes 5-fluouracil, epirubicin, and cyclophosphamide (FEC) combination chemotherapy in non-stem breast cancer cells and breast cancer stem cells. We show that this occurs through an AMPK-dependent mechanism in parental breast cancer cell lines. In contrast, the synergistic effects of metformin and FEC occurred in an AMPK-independent mechanism in breast CSCs. Further analyses revealed that metformin accelerated glucose consumption and lactate production more severely in the breast CSCs but the production of intracellular ATP was severely hampered, leading to a severe energy crisis and impairs the ability of CSCs to repair FEC-induced DNA damage. Indeed, addition of extracellular ATP completely abrogated the synergistic effects of metformin on FEC sensitivity in breast CSCs. In conclusion, our results suggest that metformin synergizes FEC sensitivity through distinct mechanism in parental breast cancer cell lines and CSCs, thus providing further evidence for the clinical relevance of metformin for the treatment of cancers.

Matched MeSH terms: Lung/cytology
High dengue virus load differentially modulates human microvascular endothelial barrier function during early infection

Soe HJ, Khan AM, Manikam R, Samudi Raju C, Vanhoutte P, Sekaran SD

J Gen Virol, 2017 Dec;98(12):2993-3007.
PMID: 29182510 DOI: 10.1099/jgv.0.000981

Plasma leakage is the main pathophysiological feature in severe dengue, resulting from altered vascular barrier function associated with an inappropriate immune response triggered upon infection. The present study investigated functional changes using an electric cell-substrate impedance sensing system in four (brain, dermal, pulmonary and retinal) human microvascular endothelial cell (MEC) lines infected with purified dengue virus, followed by assessment of cytokine profiles and the expression of inter-endothelial junctional proteins. Modelling of changes in electrical impedance suggests that vascular leakage in dengue-infected MECs is mostly due to the modulation of cell-to-cell interactions, while this loss of vascular barrier function observed in the infected MECs varied between cell lines and DENV serotypes. High levels of inflammatory cytokines (IL-6 and TNF-α), chemokines (CXCL1, CXCL5, CXCL11, CX3CL1, CCL2 and CCL20) and adhesion molecules (VCAM-1) were differentially produced in the four infected MECs. Further, the tight junctional protein, ZO-1, was down-regulated in both the DENV-1-infected brain and pulmonary MECs, while claudin-1, PECAM-1 and VE-cadherin were differentially expressed in these two MECs after infection. Non-purified virus stock was also studied to investigate the impact of virus stock purity on dengue-specific immune responses, and the results suggest that virus stock propagated through cell culture may include factors that mask or alter the DENV-specific immune responses of the MECs. The findings of the present study show that high DENV load differentially modulates human microvascular endothelial barrier function and disrupts the function of inter-endothelial junctional proteins during early infection with organ-specific cytokine production.

Matched MeSH terms: Lung/cytology