Use of nanoparticles as therapy for methicillin-resistant Staphylococcus aureus infections

Staphylococcal infection can cause a wide range of diseases resulting either from staphylococcal bacteria invasion or through toxin production. The majority of infections caused by staphylococci are due to Staphylococcus aureus. Moreover, methicillin-resistant Staphylococcus aureus has recently been considered to be one of the major causes of hospital-acquired infections. The treatment of staphylococci infections is difficult because increased antibiotic resistant strains have become more common, increasing the risk of serious health penalty. Delivery of antibiotics via nanoparticles is a promising therapy, as a drug delivery mechanism, particularly for controlled release or depot delivery of drugs to decrease the number of doses required to achieve a clinical effect. This review emphasized the potential of nanoparticles in the targeted antibiotics for therapy of staphylococcal infections.

Stimuli-responsive liposome fusion mediated by gold nanoparticles

We report a new approach to controlling the fusion activity of liposomes by adsorbing carboxyl-modified gold nanoparticles to the outer surface of phospholipid liposomes. The bound gold nanoparticles can effectively prevent liposomes from fusing with one another at neutral pH value, while at acidic environments (e.g., pH < 5), the gold particle stabilizers will detach from the liposomes, with liposome fusion activity resuming. The binding of carboxyl-modified gold nanoparticles to cationic phospholipid liposomes at neutral pH and detaching at acidic pH values are evaluated and confirmed by dynamic light scattering, electron microscopy, fluorescence and UV-vis absorption experiments. The relative fusion efficiency of gold-nanoparticle-stabilized cationic liposomes with anionic liposomes is approximately 25% at pH = 7 in contrast to approximately 80% at pH = 4. Since liposomes have been extensively used as drug nanocarriers and the infectious lesions on human skin are typically acidic with a pH < 5, these acid-responsive liposomes with tunable fusion ability hold great promise for dermal drug delivery to treat a variety of skin diseases such as acne vulgaris and staph infections.

Vaccination targeting surface FomA of Fusobacterium nucleatum against bacterial co-aggregation: Implication for treatment of periodontal infection and halitosis

The mechanical therapy with multiple doses of antibiotics is one of modalities for treatment of periodontal diseases. However, treatments using multiple doses of antibiotics carry risks of generating resistant strains and misbalancing the resident body flora. We present an approach via immunization targeting an outer membrane protein FomA of Fusobacterium nucleatum (F. nucleatum), a central bridging organism in the architecture of oral biofilms. Neutralization of FomA considerably abrogated the enhancement of bacterial co-aggregation, biofilms and production of volatile sulfur compounds mediated by an inter-species interaction of F. nucleatum with Porphyromonas gingivalis (P. gingivalis). Vaccination targeting FomA also conferred a protective effect against co-infection-induced gum inflammation. Here, we advance a novel infectious mechanism by which F. nucleatum co-opts P. gingivalis to exacerbate gum infections. FomA is highlighted as a potential target for development of new therapeutics against periodontal infection and halitosis in humans.

Systematic evaluations of skin damage irradiated by an erbium:YAG laser: histopathologic analysis, proteomic profiles, and cellular response

BACKGROUND

The erbium:yttrium-aluminum-garnet (Er:YAG) laser is used for surgical resurfacing. It has ablative properties with water as its main chromophore.

OBJECTIVE

This study attempted to establish the cutaneous effect and cellular response to Er:YAG laser irradiation using different fluences (7.5 and 15 J/cm(2)).

METHODS

Female nude mouse was used as the animal model in the study. Physiological parameters were examined and histology was evaluated at 4, 24 and 96 h after laser exposure. A proteomic analysis and immunoblotting were also used to determine the mechanisms of the laser's effect on the skin.

RESULTS

Both fluences were associated with a significant increase in transepidermal water loss (TEWL), erythema (a*), and the skin pH at 4 and 24h. In contrast, at 96 h, the levels of these parameters had generally decreased to the baseline. The histology examined by light microscopy and transmission electron microscopy (TEM) showed vacuolization, hydropic degeneration and epidermal necrosis of laser-irradiated skin. The higher fluence (15 J/cm(2)) exhibited more-severe disruption of the skin. Bulous and scarring were observed in skin treated with the higher fluence during the recovery period. p53 and p21 proteins were significantly activated in skin following exposure to the laser. However, proliferating cell nuclear antigen and cytokeratin expressions were downregulated by the low fluence (7.5 J/cm(2)).

CONCLUSION

Both proliferation and apoptosis occurred when the laser-irradiated the skin.

Commensal bacteria regulate Toll-like receptor 3-dependent inflammation after skin injury

The normal microflora of the skin includes staphylococcal species that will induce inflammation when present below the dermis but are tolerated on the epidermal surface without initiating inflammation. Here we reveal a previously unknown mechanism by which a product of staphylococci inhibits skin inflammation. This inhibition is mediated by staphylococcal lipoteichoic acid (LTA), and acts selectively on keratinocytes triggered through Toll-like receptor (TLR) 3. The significance of this is seen by observations that TLR3 activation is required for normal inflammation after injury, and that keratinocytes require TLR3 to respond to RNA from damaged cells with the release of inflammatory cytokines. Staphylococcal LTA inhibits both inflammatory cytokine release from keratinocytes and inflammation triggered by injury through a TLR2-dependent mechanism. These findings show for the first time that the skin epithelium requires TLR3 for normal inflammation after wounding and that the microflora can modulate specific cutaneous inflammatory responses.

The antimicrobial activity of liposomal lauric acids against Propionibacterium acnes

This study evaluated the antimicrobial activity of lauric acid (LA) and its liposomal derivatives against Propionibacterium acnes (P. acnes), the bacterium that promotes inflammatory acne. First, the antimicrobial study of three free fatty acids (lauric acid, palmitic acid and oleic acid) demonstrated that LA gives the strongest bactericidal activity against P. acnes. However, a setback of using LA as a potential treatment for inflammatory acne is its poor water solubility. Then the LA was incorporated into a liposome formulation to aid its delivery to P. acnes. It was demonstrated that the antimicrobial activity of LA was not only well maintained in its liposomal derivatives but also enhanced at low LA concentration. In addition, the antimicrobial activity of LA-loaded liposomes (LipoLA) mainly depended on the LA loading concentration per single liposomes. Further study found that the LipoLA could fuse with the membranes of P. acnes and release the carried LA directly into the bacterial membranes, thereby killing the bacteria effectively. Since LA is a natural compound that is the main acid in coconut oil and also resides in human breast milk and liposomes have been successfully and widely applied as a drug delivery vehicle in the clinic, the LipoLA developed in this work holds great potential of becoming an innate, safe and effective therapeutic medication for acne vulgaris and other P. acnes associated diseases.

Histone H4 is a major component of the antimicrobial action of human sebocytes

Antimicrobial peptides, such as cathelicidin and beta defensins, directly kill microbes and have been detected in human sebaceous glands and cell lines. Despite the presence of several such peptides, the apparent abundance of these is insufficient for direct killing of most skin pathogens. In this study, we sought to determine which molecules provide the majority of antimicrobial peptide activity in human sebocytes. Acid-soluble protein extracts of SEB-1 sebocytes were separated by reverse-phase high-performance liquid chromatography and were assayed for their capacity to inhibit the growth of Staphylococcus aureus. Antimicrobial activity was isolated in a single major fraction and identified to be histone H4 by mass spectrometry and western blot analysis. The importance of histone H4 in the antimicrobial activity of sebocytes was confirmed by a specific neutralizing antibody and by direct demonstration that recombinant histone H4 had antimicrobial activity against S. aureus and Propionibacterium acnes. In addition, histone H4 enhanced the antimicrobial action of free fatty acids in human sebum. Taken together, these results indicate that the release of histone H4 by holocrine secretion from the sebaceous gland may play an important role in innate immunity.

Heat shock proteins HSP27 and HSP70 are present in the skin and are important mediators of allergic contact hypersensitivity

Proteomic analysis of murine skin has shown that a variety of heat shock proteins (HSPs) are constitutively expressed in the skin. Using murine allergic contact hypersensitivity as a model, we investigated the role of two heat shock proteins, HSP27 and HSP70, in the induction of cutaneous cell-mediated immune responses. Immunohistochemical examination of skin specimens showed that HSP27 was present in the epidermis and HSP70 was present in both the epidermis and dermis. Inhibition of HSP27 and HSP70 produced a reduction in the 1-fluoro-2,4-dinitrobenzene contact hypersensitivity response and resulted in the induction of Ag-specific unresponsiveness. Treatment of dendritic cell cultures with recombinant HSP27 caused in the up-regulation of IL-1beta, TNF-alpha, IL-6, IL-12p70, and IL-12p40 but not IL-23p19, which was inhibited when Abs to HSP27 were added. The 1-fluoro-2,4-dinitrobenzene-conjugated dendritic cells that had been treated with HSP27 had an increased capacity to initiate contact hypersensitivity responses compared with control dendritic cells. This augmented capacity required TLR4 signaling because neither cytokine production by dendritic cells nor the increased induction of contact hypersensitivity responses occurred in TLR4-deficient C3H/HeJ mice. Our findings indicate that a cascade of events occurs following initial interaction of hapten with the skin that includes increased activity of HSPs, their interaction with TLR4, and, in turn, increased production of cytokines that are known to enhance Ag presentation by T cells. The results suggest that HSPs form a link between adaptive and innate immunity during the early stages of contact hypersensitivity.

Vaccines and photodynamic therapies for oral microbial-related diseases

The mouth is a favorable habitat for a great variety of bacteria. Microbial composition of dental plaque is the usual cause of various oral diseases in humans, including dental caries, periodontal disease and halitosis. In general, oral antibacterial agents such as antibiotics are commonly used to treat oral bacterial infection. Traditional periodontal surgery is painful and time-consuming. In addition, bacterial resistance and toxicity of antibiotics have become a global pandemic and unavoidable. Recently, vaccines for dental caries and periodontal disease have been developed and applied. Moreover, the use of photodynamic therapy has become an alternative to antibiotic drugs. The purpose of this article is to highlight the advantages of vaccine therapy and photodynamic therapy for oral microbial-related diseases compared to treatments with antimicrobial agents and traditional periodontal surgery.

Bioengineering a humanized acne microenvironment model: proteomics analysis of host responses to Propionibacterium acnes infection in vivo

Acne is a human disease of the sebaceous hair follicle. Unlike humans, most animals produce little or no triglycerides in hair follicles to harbor Propionibacterium acnes a fact that has encumbered the development of novel treatments for acne lesions. Although genetic mutant mice with acne-like skins have been used for screening anti-acne drugs, the mice generally have deficits in immune system that turns out to be inappropriate to generate antibodies for developing acne vaccines. Here, we employed a bioengineering approach using a tissue chamber integrated with a dermis-based cell-trapped system (DBCTS) to mimic the in vivo microenvironment of acne lesions. Human sebocyte cell lines were grown in DBCTS as a scaffold and inserted into a perforated tissue chamber. After implantation of a tissue chamber bearing human sebocytes into ICR mice, P. acnes or PBS was injected into a tissue chamber to induce host immune response. Infiltrated cells such as neutrophils and macrophages were detectable in tissue chamber fluids. In addition, a proinflammatory cytokine macrophage-inflammatory protein-2 (MIP-2) was elevated after P. acnes injection. In tissue chamber fluids, 13 proteins including secreted proteins and cell matrix derived from mouse, human cells or P. acnes were identified by proteomics using isotope-coded protein label (ICPL) coupled to nano-LC-MS analysis. After P. acnes infection, four proteins including fibrinogen, alpha polypeptide, fibrinogen beta chain, S100A9, and serine protease inhibitor A3K showed altered concentrations in the mimicked acne microenvironment. The bioengineered acne model thus provides an in vivo microenvironment to study the interaction of host with P. acnes and offers a unique set-up for screening novel anti-acne drugs and vaccines.

Analysis of ERCC2/XPD functional polymorphisms in systemic lupus erythematosus

Sunlight/ultraviolet (UV) irradiation has been recognized as an important risk factor for developing systemic lupus erythematosus (SLE). However, the interpretation of genetic variations involved in UV-light sensitivity is largely unknown. Recent studies indicated that two genetic variations of ERCC2/XPD gene (rs1799793 in exon 10 and rs13181 in exon 23) have been found to exert negative influences on nucleotide excision repair system. To analyse the possible contribution of the ERCC2/XPD functional single nucleotide polymorphisms in genetic susceptibility to SLE, the rs13181 and rs1799793 SNPs in ERCC2/XPD were genotyped by polymerase chain reaction followed by restriction fragment length polymorphism analysis. Association was studied by case-control analyses using samples from 172 SLE patients and 160 healthy controls. Haplotype analysis was performed to detect the association with genetic predisposition to SLE and the clinical features. Although these two functional genetic variations are linked to several immune dysfunction-induced diseases, no statistically significant differences in allele or genotype frequencies were observed between SLE patients and controls. Haplotype analysis showed that none of ERCC2/XPD haplotypes was associated with the incidence of SLE disease, nor the preference of clinical features. In conclusion, the ERCC2/XPD functional polymorphisms analysed in this study showed no association in genetic susceptibility to SLE.

Decreasing systemic toxicity via transdermal delivery of anticancer drugs

When used at a high dose, many anticancer drugs produce undesirable side effects including hepatotoxicity. Transdermal delivery bypasses first-pass metabolism, allowing the use of a lower dose of drug while decreasing systemic toxicity. In this review, we summarize various advanced technologies for improving anticancer drug delivery via the skin. This technology is discussed in the context of three anticancer drugs, 5-fluorouracil (5-FU), methotrexate (MTX) and 5-aminolevulinic acid (5-ALA). The use of a erbium:YAG (Er:YAG) laser for transdermal delivery of anticancer drugs is specifically highlighted in this review.

Vaccine therapy for P. acnes-associated diseases

Recent studies have afforded abundant evidences showing that Propionibacterium acnes (P. acnes) is involved not only in acne vulgaris, but also in many diseases, including endocarditis, endophthalmitis, osteomyelitis, joint, nervous system, cranial neurosurgery infections, and implanted biomaterial contamination. In spite of a range of P. acnes pathogenicity, its vaccine therapies have been studied much less intensively than antibiotic therapies which have been mainstay of treatment for P. acnes-associated diseases. Therefore, we have recently developed effective vaccines for P. acnes-associated inflammatory acne, consisting of a cell wall-anchored sialidase of P. acnes or killed-whole organism of P. acnes. Our data strongly show that immunization of ICR mice with the vaccines provides in vivo protective immunity against P. acnes challenge and decreases P. acnes-induced elevation of cytokine production. This review highlights the potential functions of killed P. acnes- and sialidase-based vaccines as novel treatments for P. acnes-associated diseases.

The lysogenic cycle of the filamentous phage Cflt from Xanthomonas campestris pv. citri

A phage, Cflt, forming turbid plaques, was isolated from Xanthomonas campestris pv. citri. After infection, infected sensitive cells become immune to Cflt and produce very few phages. These properties were genetically rather stable. The phage was purified and shown to be filamentous with a size of 1157 +/- 73 nm. The genome size is about 7.62 kb. The phage does not affect the growth of host bacteria. Under natural cultivation conditions Cflt-lysogenized cells could be induced spontaneously to give high phage yields, or cured to give phage-free cells. The integration of Cflt DNA into host DNA was proved by Southern blot hybridization. The lysogenic phage was genetically stable in log phase cells and persisted in stationary phase cells through many cell generations in the absence of extracellular phage reinfection.

Proteomics integrated with Escherichia coli vector-based vaccines and antigen microarrays reveals the immunogenicity of a surface sialidase-like protein of Propionibacterium acnes

Proteomics is a powerful tool for the identification of proteins, which provides a basis for rational vaccine design. However, it is still a highly technical and time-consuming task to examine a protein's immunogenicity utilizing traditional approaches. Here, we present a platform for effectively evaluating protein immunogenicity and antibody detection. A tetanus toxin C fragment (Tet-c) was used as a representative antigen to establish this platform. A cell wall-anchoring sialidase-like protein (SLP) of Propionibacterium acnes was utilized to assess the efficacy of this platform. We constructed an Escherichia coli vector-based vaccine by overexpressing Tet-c or SLP in E. coli and utilized an intact particle of E. coli itself as a vaccine (E. coli Tet-c or SLP vector). After ultraviolet (UV) irradiation, the E. coli vector-based vaccines were administered intranasally into imprinting control region mice without adding exogenous adjuvants. For antibody detection, we fabricated antigen microarrays by printing with purified recombinant proteins including Tet-c and SLP. Our results demonstrated that detectable antibodies were elicited in mice 6 weeks after intranasal administration of UV-irradiated E. coli vector-based vaccines. The antibody production of Tet-c and SLP was significantly elevated after boosting. Notably, the platform with main benefits of using E. coli itself as a vaccine carrier provides a critical template for applied proteomics aimed at screening novel vaccine targets. In addition, the novel immunogenic SLP potentially serves as an antigen candidate for the development of vaccines targeting P. acnes-associated diseases.

HSP70s: From Tumor Transformation to Cancer Therapy

Heat shock proteins (HSPs) are a defined set of chaperones for maintaining proper functions of proteins. The HSP70 family, one of the most inducible families in response to stress, protects cells from stress-induced cell death. It has been documented that HSP70s are highly expressed in various types of cancer cells and make the cells resistant to adverse microenvironments, such as hypoxia and glucose starvation, which are common features in malignant progression. Over-expression of HSP70s is thus associated with tumor transformation and eventually results in a decrease of chemotherapy efficacy. Notably, the distribution of HSP70s is deregulated in cancer cells. It has been reported that HSP70s localize distinct organelles or are exported to humoral circulation during cancer development. Either surface or exported HSP70s play danger signals and trigger immune response to destroy the tumor cells. In this review, we lay out recent advances in the HSP70s-mediated cancer diagnosis and therapy. This review would be enlightening for clinical cancer medicine.

In vivo tumor secretion probing via ultrafiltration and tissue chamber: implication for anti-cancer drugs targeting secretome

Tumor secreted proteins/peptides (tumor secretome) act as mediators of tumor-host communication in the tumor microenvironment. Therefore, development of anti-cancer drugs targeting secretome may effectively control tumor progression. Novel techniques including a capillary ultrafiltration (CUF) probe and a dermis-based cell-trapped system (DBCTS) linked to a tissue chamber were utilized to sample in vivo secretome from tumor masses and microenvironments. The CUF probe and tissue chamber were evaluated in the context of in vivo secretome sampling. Both techniques have been successfully integrated with mass spectrometry for secretome identification. A secretome containing multiple proteins and peptides can be analyzed by NanoLC-LTQ mass spectrometry, which is specially suited to identifying proteins in a complex mixture. In the future, the establishment of comprehensive proteomes of various host and tumor cells, as well as plasma will help in distinguishing the cellular sources of secretome. Many detection methods have been patented regarding probes and peptide used for identification of tumors.