Airway Epithelial Cells Condition Dendritic Cells to Express Multiple Immune Surveillance Genes

Increasing evidence suggests that crosstalk between airway epithelial cells (AEC) and adjacent dendritic cells (DC) tightly regulates airway mucosal DC function in steady state. AEC are known to express multiple immmuno-modulatory factors, though detailed information on how this influences human DC function remains incomplete. We recently demonstrated using an in vitro coculture model that AEC alter differentiation of monocytes into DC in a manner that inhibits expression of potentially damaging Th2 effector function. In the current study, we have extended these findings to examine other aspects of DC function. Using micro-array technology we show that multiple genes important for immune surveillance are significantly over expressed in purified AEC-conditioned DC, compared to control DC. These findings were confirmed by quantitative real time PCR or flow cytometry in an independent sample set. In particular, AEC-conditioned DC showed selective upregulation of chemokines that recruit Th1 cells, but minimal change in chemokines linked to Th2 cell recruitment. AEC-conditioned DC were also characterized by enhanced expression of complement family genes (C1QB, C2, CD59 and SERPING1), Fcγ receptor genes (FCGR1A, FCGR2A, FCGR2B and FCGR2C), signaling lymphocytic activation molecule family member 1 (SLAM), programmed death ligands 1 and 2, CD54 and CD200R1, relative to control DC. These findings suggest that AEC conditioning facilitates the capacity of DC to react to danger signals, to enhance leukocyte recruitment, especially of Th1 effector cells, and to interact with other immune cell populations while minimizing the risks of excessive inflammation leading to tissue damage.     

Fast calculation of the quartet distance between trees of arbitrary degrees

Background  

A number of algorithms have been developed for calculating the quartet distance between two evolutionary trees on the same set of species. The quartet distance is the number of quartets – sub-trees induced by four leaves – that differs between the trees. Mostly, these algorithms are restricted to work on binary trees, but recently we have developed algorithms that work on trees of arbitrary degree.     

A newly recognized family from the Horn of Africa,the Heterocephalidae (Rodentia: Ctenohystrica)

The Ctenohystrica is one of the three major lineages of rodents and contains diverse forms related to gundis, porcupines, and guinea pigs. Phylogenetic analyses of this group using mitochondrial and nuclear gene sequences confirm the monophyly of the infraorder Hystricognathi and most of its recognized subclades, including both the Neotropical caviomorphs and the African phiomorphs, which are recovered as sister groups. Molecular timetrees calibrated with 22 securely placed fossils indicate that hystricognath superfamilies originated in the Eocene and Oligocene and most families had appeared by the end of the Oligocene, ～23 Mya. Divergences leading to hystricognath genera took place in the Miocene and Pliocene, with a single exception. The naked mole‐rat (Heterocephalus) diverged from other African mole‐rats (Bathyergidae) in the early Oligocene (～31.2 Mya), when the four caviomorph superfamilies (Erethizonoidea and Cavioidea at 32.4 Mya, Chinchilloidea and Octodontoidea at 32.8 Mya) were first appearing in South America. The extended independent evolution of Heterocephalus suggested by this analysis prompted a closer examination of mole‐rat characters. Heterocephalus indeed shares many characters with bathyergids, befitting their joint membership in the parvorder Bathyergomorphi and superfamily Bathyergoidea as well as their shared exploitation of subterranean lifestyles. However, a diverse array of cranial, dental, postcranial, external, and ecological characters distinguishes Heterocephalus from other African mole‐rats. These differences equal or exceed those used to diagnose caviomorph families and justify recognizing the naked mole‐rat in its own family, Heterocephalidae Landry, 1957. This taxonomic arrangement poses questions for the inter‐relationships of fossil and extant mole‐rats and brings time equivalence to the ranks assigned to the major clades of hystricognaths. © 2014 The Linnean Society of London