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Byline: Uppala. Ratnamala, Nayan. Jain, Devendrasinh. Jhala, Pullabatla. S. Prasad, Nazia. Saiyed, Sreelatha. Nair, Uppala. Radhakrishna Background: Hidradenitis suppurativa (HS) is a complex, chronic inflammatory skin disorder whose pathophysiology is [...]

13-cis retinoic acid (13-cis RA; also known as isotretinoin) is the most potent agent available for treatment of acne. It is known that the drug induces apoptosis in cells cultured from human sebaceous glands, but its mechanism of action has not been determined. In this study, skin biopsies were taken from 7 patients with acne prior to and at 1 week of treatment with 13-cis RA. TUNEL staining confirmed that 13-cis RA induced apoptosis in sebaceous glands. Transcriptional profiling of patient skin and cultured human sebaceous gland cells (SEB-1 sebocytes) indicated that lipocalin 2 was among the genes most highly upregulated by 13-cis RA. Lipocalin 2 encodes neutrophil gelatinase--associated lipocalin (NGAL), which functions in innate immune defense and induces apoptosis of murine B lymphocytes. Increased immunolocalization of NGAL was noted in patients' sebaceous glands following treatment with 13-cis RA, and recombinant NGAL induced apoptosis in SEB-1 sebocytes. Furthermore, apoptosis in response to 13-cis RA was inhibited in the presence of siRNA to lipocalin 2. These data indicate that NGAL mediates the apoptotic effect of 13-cis RA and suggest that agents that selectively induce NGAL expression in sebaceous glands might represent therapeutic alternatives to the use of 13-cis RA to treat individuals with acne., Introduction 13-cis retinoic acid (13-cis RA, also known as isotretinoin) is the most effective drug for the treatment of acne. It is also used to treat pediatric patients with neuroblastoma [...]

Abstract The genome of Propionibacterium acnes, the microbe presumed to be at least partially etiologic for the development of acne, has recently been decoded. The genome supports long-standing concepts regarding [...]

Cutaneous propionibacteria are important commensals of human skin and are implicated in a wide range of opportunistic infections. Propionibacterium acnes is also associated with inflammatory acne vulgaris. Bacteriophage PA6 is the first phage of P. acnes to be sequenced and demonstrates a high degree of similarity to many mycobacteriophages both morphologically and genetically. PA6 possesses an icosahedreal head and long noncontractile tail characteristic of the Siphoviridae. The overall genome organization of PA6 resembled that of the temperate mycobacteriophages, although the genome was much smaller, 29,739 bp (48 predicted genes), compared to, for example, 50,550 bp (86 predicted genes) for the Bxb1 genome. PA6 infected only P. acnes and produced clear plaques with turbid centers, but it lacked any obvious genes for lysogeny. The host range of PA6 was restricted to P. acnes, but the phage was able to infect and lyse all P. acnes isolates tested. Sequencing of the PA6 genome makes an important contribution to the study of phage evolution and propionibacterial genetics.

Despite accumulating data implicating Propionibacterium acnes in a variety of diseases, its precise role in infection remains to be determined. P. acnes antigen-specific CD[4.sup.+] T cells are present in early inflamed acne lesions and may be involved in the inflammatory response; however, little is known about the specific antigens involved. In this study, B cell and T cell antigens from P. acnes expression libraries were cloned and evaluated and the four predominant proteins identified were investigated. Two of these antigens share some homology with an M-like protein of Streptococcus equi and have dermatan-sulphate-binding activity (PA-25957 and 5541). The remaining two antigens, PA-21693 and 4687, are similar to the product of the Corynebacterium diphtheriae htaA gene from the hmu ABC transport locus, although only one of these (PA-21693) is encoded within an hmu-like operon and conserved amongst a range of clinical isolates. All four proteins contain an LPXTG motif, although only PA-21693 contains a characteristic sortase-sorting signal. Variation in the expression of PA-4687, 25957 and 5541 is evident amongst clinical isolates and is generated both by frameshifts associated with the putative signal peptide and by variable numbers of repeat regions toward the carboxy-terminus, potentially generating heterogeneity of molecular mass and antigenic variation. In addition, in the case of PA-25957, a frameshift in a C-rich region at the extreme carboxy-terminus eliminates the LPXTG motif in some isolates. For the dermatan-sulphate-binding PA-25957, IgG1 antibody in serum from acne-positive donors was shown to be specific for the amino-terminal region of the protein, which also contains a CD[4.sup.+] T cell epitope. In contrast, serum from ache-negative donors shows an IgG2 and IgG3 antibody subclass response to the carboxy-terminal region. These data have implications for the potential role of P. acnes in inflammatory acne and other diseases. DOI: 10.1099/mic.0.29219-0

DNA quantification is used to measure growth and autolysis in mixed populations of Lactococcus lactis subsp. lactis and three different species of Propionibacterium. Result shows that L. lactis subsp. lactis INF L2 autolyzes first, followed by Propionibacterium acidipropionici ATCC 4965, Propionibacterium freudenreichii ISU P59, and then Propionibacterium jensenii INF P303.

Analysis of the draft genome sequence of the opportunistic pathogen Propionibacterium acnes type strain NCTC 737 (= ATCC 6919) revealed five genes with sequence identity to the co-haemolytic Christie--Atkins--Munch-Peterson (CAMP) factor of Streptococcus agalactiae. The predicted molecular masses for the expressed proteins ranged from 28 to 30 kDa. The genes were present in each of the three recently identified recA-based phylogenetic groupings of P. acnes (IA, IB and II), as assessed by PCR amplification. Conserved differences in CAMP factor gene sequences between these three groups were also consistent with their previous phylogenetic designations. All type IA, IB and II isolates were positive for the co-haemolytic reaction on sheep blood agar. Immunoblotting and silver staining of SDS-PAGE gels, however, revealed differential protein expression of CAMP factors amongst the different groups. Type IB and II isolates produced an abundance of CAMP factor 1, detectable by specific antibody labelling and silver staining of SDS-PAGE gels. In contrast, abundant CAMP factor production was lacking in type IA isolates, although larger amounts of CAMP factor 2 were detectable by immunoblotting compared with type II isolates. While the potential role of the abundant CAMP factor 1 in host colonization or virulence remains to be determined, it should be noted that the type strain of P. acnes used in much of the published literature is a type IA isolate and is, therefore, lacking in this attribute.

Byline: Raj. Kubba, A. Bajaj, D. Thappa, Rajeev. Sharma, Maya. Vedamurthy, Sandipan. Dhar, S. Criton, Rui. Fernandez, A. Kanwar, Uday. Khopkar, Malavika. Kohli, V. Kuriyipe, Koushik. Lahiri, Nina. Madnani, Deepak. [...]

The development and application of a [beta]-galactosidase reporter system for the analysis of promoter elements in Propionibacterium freudenreichii is reported. The pTD210 reporter vector system produced accurate and reproducible measurements that allowed both promoter identification and the quantification of promoter activities.