Dectin-1-dependent LC3 recruitment to phagosomes enhances fungicidal activity in macrophages

Autophagy has been postulated to play role in mammalian host defense against fungal pathogens, although the molecular details remain unclear. Here, we show that primary macrophages deficient in the autophagic factor LC3 demonstrate diminished fungicidal activity but increased cytokine production in response to Candida albicans stimulation. LC3 recruitment to fungal phagosomes requires activation of the fungal pattern receptor dectin-1. LC3 recruitment to the phagosome also requires Syk signaling but is independent of all activity by Toll-like receptors and does not require the presence of the adaptor protein Card9. We further demonstrate that reactive oxygen species generation by NADPH oxidase is required for LC3 recruitment to the fungal phagosome. These observations directly link LC3 to the inflammatory pathway against C. albicans in macrophages.

Dectin-1 activation controls maturation of β-1,3-glucan-containing phagosomes

Elimination of fungal pathogens by phagocytes requires phagosome maturation, a process that involves the recruitment and fusion of intracellular proteins. The role of Dectin-1, a β-1,3-glucan receptor, critical for fungal recognition and triggering of Th17 responses, to phagosomal maturation has not been defined. We show that GFP-Dectin-1 translocates to the fungal phagosome, but its signal decays after 2 h. Inhibition of acidification results in retention of GFP-Dectin-1 to phagosome membranes highlighting the requirement for an acidic pH. Following β-1,3-glucan recognition, GFP-Dectin-1 undergoes tyrosine phosphorylation by Src kinases with subsequent Syk activation. Our results demonstrate that Syk is activated independently of intraphagosomal pH. Inhibition of Src or Syk results in prolonged retention of GFP-Dectin-1 to the phagosome signifying a link between Syk and intraphagosomal pH. β-1,3-glucan phagosomes expressing a signaling incompetent Dectin-1 failed to mature as demonstrated by prolonged Dectin-1 retention, presence of Rab5B, failure to acquire LAMP-1 and inability to acidify. Phagosomes containing Candida albicans also require Dectin-1-dependent Syk activation for phagosomal maturation. Taken together, these results support a model where Dectin-1 not only controls internalization of β-1,3-glucan containing cargo and triggers proinflammatory cytokines, but also acts as a master regulator for subsequent phagolysosomal maturation through Syk activation.

Dental education in the 21st century

The continuum of dental education has been greatly strengthened by the General Dental Council's educational initiatives during the past five years and these are described in this paper: lifelong learning and recertification will reassure the public and full integration of team members through statutory registration with one self-regulatory body is an innovation in the regulation of health professionals. Future training and educational strategies, including the health science concept, for team members are explored.

The changing role of specialist care in NHS dentistry

Specialisation and Specialist Training in Dentistry in the UK have been central issues for debate in the last few years. The profession has emerged stronger in understanding the respective roles of the generalist who should remain free to practise across the whole spectrum of dentistry and the specialist who can work in primary and secondary care. The overriding principle is that the patient remains the true beneficiary of a specialised service within the NHS.

United we stand: divided we fall

This is an abridged version of Margaret Seward's Donald Taylor Memorial Lecture delivered on February 20, 1996, during the 75th anniversary celebrations of the Royal Army Dental Corps. The annual lecture is held to honour the unique contribution of Brigadier Donald Vernon Taylor CBE to the RADC and to the wider profession of dentistry.

Western Asia--a college visit

The first newspaper for a fortnight is always read avidly by any homeward bound traveller. So it was for the passengers on Flight KL872 on Monday, November 4 after a Conference in Pakistan and India with the Royal College of Surgeons of England. It was not long before Guardian readers had found the article 'In the ruins of the Raj' by Mark Tully.* Uncannily, it recounted the splendour and majesty of the countries we had visited and yet, at the same time, expressed our fears for the future of these delightfully hospitable and intelligent people who had been our hosts in Pakistan and India for two weeks.

Congenital malformations in aborigines and non-aborigines in Western Australia, 1980-1987

A comparison of congenital malformations in Aboriginal and non-Aboriginal children in Western Australia has been made by means of data from the WA Congenital Malformations Registry, for births from 1980 to 1987 inclusive. Although the birth prevalence of all malformations was 3.5% for both Aboriginal and non-Aboriginal infants, significant differences were found in the birth prevalence of some individual malformations. Nervous-system and cardiovascular defects, and cleft lip and palate were significantly more prevalent in Aborigines, and pyloric stenosis and urogenital defects were significantly less prevalent. While some of the observed differences may have been a result of biases in ascertainment, others are likely to represent true differences. A discussion of Aboriginal beliefs concerning conception and birth is included, in order that the quantitative findings from the study might be considered in an appropriate cultural setting.