Ameloblasts require active RhoA to generate normal dental enamel

RhoA plays a fundamental role in regulation of the actin cytoskeleton, intercellular attachment and cell proliferation. During amelogenesis, ameloblasts which produce the enamel proteins undergo dramatic cytoskeletal changes and RhoA protein level is upregulated. Transgenic mice were generated that express a dominant-negative RhoA transgene in ameloblasts using amelogenin gene regulatory sequences. Transgenic and WT molar tooth germs were incubated with NaF or NaCl in organ culture. F-actin stained with phalloidin was elevated significantly in WT ameloblasts treated with NaF compared to WT ameloblasts treated with NaCl or compared to transgenic ameloblasts treated with NaF, thereby confirming a block in the RhoA/ROCK pathway in the transgenic mice. Little difference in quantitative fluorescence (estimation of fluorosis) was observed between WT and transgenic incisors from mice provided NaF in their drinking water. We subsequently found reduced transgene expression in incisors compared to molars. Transgenic molar teeth had reduced amelogenin, E-cadherin and Ki67 compared to WT. Hypoplastic enamel in transgenic mice correlates with reduced expression of the enamel protein amelogenin, and E-cadherin and cell proliferation are regulated by RhoA in other tissues. Together these findings reveal deficits in molar ameloblast function when RhoA activity is inhibited

Placental Toll-Like Receptor 3 and Toll-Like Receptor 7/8 Activation Contributes to Preeclampsia in Humans and Mice

Preeclampsia (PE) is a pregnancy-specific hypertensive syndrome characterized by excessive maternal immune system activation, inflammation, and endothelial dysfunction. Toll-like receptor (TLR) 3 activation by double-stranded RNA (dsRNA) and TLR7/8 activation by single-stranded RNA (ssRNA) expressed by viruses and/or released from necrotic cells initiates a pro-inflammatory immune response; however it is unknown whether viral/endogenous RNA is a key initiating signal that contributes to the development of PE. We hypothesized that TLR3/7/8 activation will be evident in placentas of women with PE, and sufficient to induce PE-like symptoms in mice. Placental immunoreactivity and mRNA levels of TLR3, TLR7, and TLR8 were increased significantly in women with PE compared to normotensive women. Treatment of human trophoblasts with the TLR3 agonist polyinosine-polycytidylic acid (poly I:C), the TLR7-specific agonist imiquimod (R-837), or the TLR7/8 agonist CLO97 significantly increased TLR3/7/8 levels. Treatment of mice with poly I:C, R-837, or CLO97 caused pregnancy-dependent hypertension, endothelial dysfunction, splenomegaly, and placental inflammation. These data demonstrate that RNA-mediated activation of TLR3 and TLR7/8 plays a key role in the development of PE

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Second generation of diazachrysenes: Protection of Ebola virus infected mice and mechanism of action

Ebola virus (EBOV) causes a deadly hemorrhagic fever in humans and non-human primates. There is currently no FDA-approved vaccine or medication to counter this disease. Here, we report on the design, synthesis and anti-viral activities of two classes of compounds which show high potency against EBOV in both in vitro cell culture assays and in vivo mouse models Ebola viral disease. These compounds incorporate the structural features of cationic amphiphilic drugs (CAD), i.e they possess both a hydrophobic domain and a hydrophilic domain consisting of an ionizable amine functional group. These structural features enable easily diffusion into cells but once inside an acidic compartment their amine groups became protonated, ionized and remain trapped inside the acidic compartments such as late endosomes and lysosomes. These compounds, by virtue of their lysomotrophic functions, blocked EBOV entry. However, unlike other drugs containing a CAD moiety including chloroquine and amodiaquine, compounds reported in this study display faster kinetics of accumulation in the lysosomes, robust expansion of late endosome/lysosomes, relatively more potent suppression of lysosome fusion with other vesicular compartments and inhibition of cathepsins activities, all of which play a vital role in anti-EBOV activity. Furthermore, the diazachrysene 2 (ZSML08) that showed most potent activity against EBOV in in vitro cell culture assays also showed significant survival benefit with 100% protection in mouse models of Ebola virus disease, at a low dose of 10 mg/kg/day. Lastly, toxicity studies in vivo using zebrafish models suggest no developmental defects or toxicity associated with these compounds. Overall, these studies describe two new pharmacophores that by virtue of being potent lysosomotrophs, display potent anti-EBOV activities both in vitro and in vivo animal models of EBOV disease

Inflammation-related genes significantly (p<0.05 vs. P) altered in placentas of mice treated with a TLR3, TLR7, or TLR7/8 agonist during pregnancy.

<p>P = pregnant, P+TLR3 = pregnant+TLR3 agonist poly I:C, P+TLR7 = pregnant+TLR7 agonist R837, P+TLR7/8 = pregnant+TLR7/8 agonist CLO97. All p<0.05 vs. P, n>3 in each group.</p

TLR3/7/8 activation in pregnant mice caused PE-like symptoms.

<p>Measures of (A) urinary protein concentration, (B) maternal body weight, (C) spleen weight/body weight, (D) litter weight, and (E) number of total pups/litter and fetal demise/litter in pregnant mice treated with the TLR3 agonist poly I:C, the TLR7 agonist R837, or the TLR7/8 agonist CLO97. Results are expressed as mean + SEM and n = 9 in each group. *p<0.05 vs. P.</p

Placental TLR3/7/8 activation in pregnant mice.

<p>Fold-increase and representative images and densitometric analyses of TLR3, TLR7, and TLR8 mRNA and protein levels, respectively, from 4 independent experiments in mice treated with (A) the TLR3 agonist poly I:C and (B) the TLR7 agonist R837 and the TLR7/8 agonist CLO97. Results are expressed as mean + SEM. *p<0.05 vs P.</p

TLR3/7/8 activation in human trophoblasts.

<p>Representative images and densitometric analyses of TLR3, TLR7, and TLR8 protein levels from 4 independent experiments for (A) the TLR3 agonist poly I:C, (B) the TLR7 agonist R837, and (C) the TLR7/8 agonist CLO97. Results are expressed as mean + SEM. *p<0.05 vs baseline.</p