Intestinal epithelial cell-intrinsic deletion of Setd7 identifies role for developmental pathways in immunity to helminth infection

The intestine is a common site for a variety of pathogenic infections. Helminth infections continue to be major causes of disease worldwide, and are a significant burden on health care systems. Lysine methyltransferases are part of a family of novel attractive targets for drug discovery. SETD7 is a member of the Suppressor of variegation 3-9-Enhancer of zeste-Trithorax (SET) domain-containing family of lysine methyltransferases, and has been shown to methylate and alter the function of a wide variety of proteins in vitro. A few of these putative methylation targets have been shown to be important in resistance against pathogens. We therefore sought to study the role of SETD7 during parasitic infections. We find that Setd7-/- mice display increased resistance to infection with the helminth Trichuris muris but not Heligmosomoides polygyrus bakeri. Resistance to T. muris relies on an appropriate type 2 immune response that in turn prompts intestinal epithelial cells (IECs) to alter differentiation and proliferation kinetics. Here we show that SETD7 does not affect immune cell responses during infection. Instead, we found that IEC-specific deletion of Setd7 renders mice resistant to T. muris by controlling IEC turnover, an important aspect of anti-helminth immune responses. We further show that SETD7 controls IEC turnover by modulating developmental signaling pathways such as Hippo/YAP and Wnt/β-Catenin. We show that the Hippo pathway specifically is relevant during T. muris infection as verteporfin (a YAP inhibitor) treated mice became susceptible to T. muris. We conclude that SETD7 plays an important role in IEC biology during infection

Moyal star product approach to the Bohr-Sommerfeld approximation

The Bohr-Sommerfeld approximation to the eigenvalues of a one-dimensional quantum Hamiltonian is derived through order $\hbar^2$ (i.e., including the first correction term beyond the usual result) by means of the Moyal star product. The Hamiltonian need only have a Weyl transform (or symbol) that is a power series in $\hbar$, starting with $\hbar^0$, with a generic fixed point in phase space. The Hamiltonian is not restricted to the kinetic-plus-potential form. The method involves transforming the Hamiltonian to a normal form, in which it becomes a function of the harmonic oscillator Hamiltonian. Diagrammatic and other techniques with potential applications to other normal form problems are presented for manipulating higher order terms in the Moyal series.Comment: 27 pages, no figure

AT1 Receptor Blockade Prevents the Increase in Blood Pressure and the Augmentation of Intrarenal ANG II Levels in Hypertensive Cyp1a1-Ren2 Transgenic Rats Fed With a High-Salt Diet

BACKGROUND: The present study was performed to determine the effects of high-salt diet on the magnitude of the increases in systolic blood pressure (SBP) and kidney tissue ANG II levels that occur following induction of ANG II-dependent malignant hypertension in Cyp1a1-Ren2 transgenic rats with inducible expression of the mouse Ren2 renin gene [strain name: TGR (Cyp1a1Ren2)]. METHODS: Cyp1a1-Ren2 rats (n=6) were fed a normal diet containing 0.3% indole-3-carbinol (I3C) for 10 days to induce ANG II-dependent malignant hypertension. RESULTS: Rats induced with I3C exhibited increases in (SBP) and elevations of ANG II levels in kidney cortex and medulla. In a second group of rats (n=6), high salt intake alone did not alter basal SBP; however, subsequent dietary administration of 0.3% I3C during continued high salt intake elicited a substantially greater increase in SBP than observed in rats fed a normal salt diet. ANG II levels in kidney cortex and medulla of rats induced with I3C and fed a high salt diet were elevated similarly to those in rats induced with I3C alone. Chronic administration of the AT(1) receptor antagonist, losartan (100 mg/L in drinking water, n=6), markedly attenuated the I3C-induced increase in SBP and prevented the augmentation of ANG II levels in kidney cortex and medulla in rats induced with I3C and maintained on a high salt diet. CONCLUSIONS: Activation of AT(1) receptors contributes to the augmented blood pressure and elevated kidney tissue ANG II levels that occur in Cyp1a1-Ren2 transgenic rats with malignant hypertension maintained on a high salt diet

G9a regulates group 2 innate lymphoid cell development by repressing the group 3 innate lymphoid cell program.

Innate lymphoid cells (ILCs) are emerging as important regulators of homeostatic and disease-associated immune processes. Despite recent advances in defining the molecular pathways that control development and function of ILCs, the epigenetic mechanisms that regulate ILC biology are unknown. Here, we identify a role for the lysine methyltransferase G9a in regulating ILC2 development and function. Mice with a hematopoietic cell-specific deletion of G9a (Vav.G9a(-/-) mice) have a severe reduction in ILC2s in peripheral sites, associated with impaired development of immature ILC2s in the bone marrow. Accordingly, Vav.G9a(-/-) mice are resistant to the development of allergic lung inflammation. G9a-dependent dimethylation of histone 3 lysine 9 (H3K9me2) is a repressive histone mark that is associated with gene silencing. Genome-wide expression analysis demonstrated that the absence of G9a led to increased expression of ILC3-associated genes in developing ILC2 populations. Further, we found high levels of G9a-dependent H3K9me2 at ILC3-specific genetic loci, demonstrating that G9a-mediated repression of ILC3-associated genes is critical for the optimal development of ILC2s. Together, these results provide the first identification of an epigenetic regulatory mechanism in ILC development and function

Intestinal Epithelial Cell-Intrinsic Deletion of Setd7 Identifies Role for Developmental Pathways in Immunity to Helminth Infection

The intestine is a common site for a variety of pathogenic infections. Helminth infections continue to be major causes of disease worldwide, and are a significant burden on health care systems. Lysine methyltransferases are part of a family of novel attractive targets for drug discovery. SETD7 is a member of the Suppressor of variegation 3-9-Enhancer of zeste-Trithorax (SET) domain-containing family of lysine methyltransferases, and has been shown to methylate and alter the function of a wide variety of proteins in vitro. A few of these putative methylation targets have been shown to be important in resistance against pathogens. We therefore sought to study the role of SETD7 during parasitic infections. We find that Setd7-/- mice display increased resistance to infection with the helminth Trichuris muris but not Heligmosomoides polygyrus bakeri. Resistance to T. muris relies on an appropriate type 2 immune response that in turn prompts intestinal epithelial cells (IECs) to alter differentiation and proliferation kinetics. Here we show that SETD7 does not affect immune cell responses during infection. Instead, we found that IEC-specific deletion of Setd7 renders mice resistant to T. muris by controlling IEC turnover, an important aspect of anti-helminth immune responses. We further show that SETD7 controls IEC turnover by modulating developmental signaling pathways such as Hippo/YAP and Wnt/β-Catenin. We show that the Hippo pathway specifically is relevant during T. muris infection as verteporfin (a YAP inhibitor) treated mice became susceptible to T. muris. We conclude that SETD7 plays an important role in IEC biology during infection

Effects of angiotensin II receptor blockade on proximal fluid uptake in the rat kidney

1. Angiotensin II has a well described dose-dependent biphasic action on proximal tubule fluid uptake, although the concentration and effect of endogenous luminal angiotensin II remain controversial. 2. Shrinking split-droplet micropuncture was used to examine the fluid uptake in response to the luminal application of three AT(1) antagonists (losartan, EXP3174, candesartan). 3. Addition of losartan at 10(−8) M decreased fluid uptake rate (Jv(a)) by 17.5±2.2% (P<0.05). Luminal addition of EXP3174 at concentrations between 10(−9)–10(−5) M caused a dose-dependent decrease in fluid uptake, with a maximum decrease of 41.0±9.5% (P<0.01) at 10(−6) M. Candesartan also decreased fluid uptake, by 21.9±4.9% (P<0.05) at 10(−8) M and 23.6±5.5% (P<0.05) at 10(−5) M. 4. All three antagonists at a low concentration (10(−8) M) decreased fluid uptake. EXP3174 and candesartan at a higher concentration (10(−5) M) also decreased fluid uptake in contrast to the previously reported effect of losartan. 5. We conclude that the endogenous concentration of antiotensin II in the proximal luminal fluid is low and exerts a stimulatory effect on fluid absorption. Losartan at concentrations greater than 10(−6) M may have a non-selective action on fluid uptake

<i>Setd7</i> regulates IEC turnover responses after <i>T</i>. <i>muris</i> infection.

<p>(A) H&E stained caecal sections of <i>Setd7</i>^f/f and <i>Setd7</i>^ΔIEC mice at day 14 and day 21 post infection with <i>T</i>. <i>muris</i>. Yellow lines indicate crypt length. Original magnification is 100X. Bar = 50 μm (B) Crypt length (au = arbitrary units) of caecums of naïve (day 0) and <i>T</i>. <i>muris</i> infected mice (day 14 and day 21 post infection). (n≥30 of at least 4 mice, * P<0.05, *** P<0.001). (C) Proliferation as measured by counting Ki67+ cells per crypt from images such as in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005876#ppat.1005876.s004" target="_blank">S4A</a>. (n≥20 of at least 4 mice, *** P<0.001). (D) IEC turnover was determined by dividing Ki67+ cells by total DAPI+ cells from images such as shown in <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005876#ppat.1005876.s004" target="_blank">S4A</a>. Of note, crypt length correlated with total DAPI+ cells per crypt at all time points (see <a href="http://www.plospathogens.org/article/info:doi/10.1371/journal.ppat.1005876#ppat.1005876.s004" target="_blank">S4C</a>). (n≥20 of at least 4 mice, *** P<0.001).</p

Inhibition of YAP-TEAD interactions <i>in vivo</i> in resistance to <i>T</i>. <i>muris</i>.

<p>(A) IEC-specific expression of Wnt (<i>Lgr5</i>) and Hippo (<i>Ctgf</i>) target genes in <i>T</i>. <i>muris</i> infected <i>Setd7</i>^f/f (black bars) and <i>Setd7</i>^ΔIEC (grey bars) mice. Expression is relative to naïve mice (white bars). (n≥8, ** P<0.01). (B) Worm burdens at day 21 post infection of wild type (WT) mice. Mice were either vehicle treated (black bars) or vertepofin (VP) treated (striped bars) (n≥6). (C) Gene expression of <i>Il13</i> and <i>Ifng</i> from proximal colon at day 21 post infection. Expression is relative to uninfected, untreated WT mice (white bars, WT naive). (n≥6, * P<0.05) (D & E) IEC-specific expression of effector (<i>Tslp</i> and <i>Muc5AC</i>) and Hippo and Wnt target (<i>Ctgf</i> and <i>Lgr5)</i> genes. Expression is relative to naïve mice (white bars). (n≥6, *** P<0.001).</p