Neuronal energy-sensing pathway promotes energy balance by modulating disease tolerance.

The starvation-inducible coactivator cAMP response element binding protein (CREB)-cAMP-regulated transcription coactivator (Crtc) has been shown to promote starvation resistance in Drosophila by up-regulating CREB target gene expression in neurons, although the underlying mechanism is unclear. We found that Crtc and its binding partner CREB enhance energy homeostasis by stimulating the expression of short neuropeptide F (sNPF), an ortholog of mammalian neuropeptide Y, which we show here is a direct target of CREB and Crtc. Neuronal sNPF was found to promote energy homeostasis via gut enterocyte sNPF receptors, which appear to maintain gut epithelial integrity. Loss of Crtc-sNPF signaling disrupted epithelial tight junctions, allowing resident gut flora to promote chronic increases in antimicrobial peptide (AMP) gene expression that compromised energy balance. Growth on germ-free food reduced AMP gene expression and rescued starvation sensitivity in Crtc mutant flies. Overexpression of Crtc or sNPF in neurons of wild-type flies dampens the gut immune response and enhances starvation resistance. Our results reveal a previously unidentified tolerance defense strategy involving a brain-gut pathway that maintains homeostasis through its effects on epithelial integrity.

Visible-Light-Induced Desaturative ß-Alkoxyoxalylation of N-Aryl Cyclic Amines with Difluoromethyl Bromides and H2O Via a Triple Cleavage Process.

A visible-light-driven desaturative ß-alkoxyoxalyation of N-aryl cyclic amines with difluoromethyl bromides and H2O has been reported. This tandem reaction is triggered by homolysis of the C-Br bond to produce the difuoroalkyl radical, which undergoes the subsequent defluorinated ß-alkoxyoxalylation cascades to afford a wide range of ß-ketoester/ketoamides substituted enamines. The prominent feature of this reaction contains photocatalyst-free, transition-metal free, and mild conditions. The 18O labeling experiment disclosed that H2O is the oxygen source of the carbonyl unit.

eIF4A controls germline stem cell self-renewal by directly inhibiting BAM function in the Drosophila ovary.

Stem cell self-renewal is controlled by concerted actions of extrinsic niche signals and intrinsic factors in a variety of systems. Drosophila ovarian germline stem cells (GSCs) have been one of the most productive systems for identifying the factors controlling self-renewal. The differentiation factor BAM is necessary and sufficient for GSC differentiation, but it still remains expressed in GSCs at low levels. However, it is unclear how its function is repressed in GSCs to maintain self-renewal. Here, we report the identification of the translation initiation factor eIF4A for its essential role in self-renewal by directly inactivating BAM function. eIF4A can physically interact with BAM in Drosophila S2 cells and yeast cells. eIF4A exhibits dosage-specific interactions with bam in the regulation of GSC differentiation. It is required intrinsically for controlling GSC self-renewal and proliferation but not survival. In addition, it is required for maintaining E-cadherin expression but not BMP signaling activity. Furthermore, BAM and BGCN together repress translation of E-cadherin through its 3' UTR in S2 cells. Therefore, we propose that BAM functions as a translation repressor by interfering with translation initiation and eIF4A maintains self-renewal by inhibiting BAM function and promoting E-cadherin expression.

[Studies on the estimation of soil organic matter content based on hyper-spectrum].

Hyperspectral remote sensing technology can be extensively applied in soil nutrient research due to its three special advantages, high spectral resolution, strong waveband continuity as well as a great deal of spectral information. Based on analyzing the soil organic matter content using hyper-spectral remote sensing technology, soil nutrients status and its dynamic changes can be fully understood, thus providing the scientific basis for guidance of the agricultural production and protection of agricultural ecological environment. The present paper studies the relationship between soil spectrum and soil organic fraction based on spectrum curves (ranging from 350 to 2500 nm) of 34 soil samples, which were collected in Yujiang and Taihe County, Jiangxi Province. First, soil reflection spectrum was mathematically manipulated into first derivative reflectance spectra (FDR) and inverse-log spectra (log(1/R)); second, the relationship between soil spectrum and soil organic fraction was investigated by step-wise multiple linear regression (SMLR) and partial least square regression (PLSR) on the ground of characteristic absorption; third, corresponding estimation model was built and examined. The result conveys that spectral data are compressed by carrying out arithmetic average operation by 10 nm for intervals. The first derivative of the reflectivity is an effective spectrum indicator, in the stepwise multiple linear regression analysis of soil organic matter, for the first derivative transformation, the regression models' precision of establishment and verification increased. The model built by PLSR method based on the characteristic absorption bands precedes that of SMLR. In the PLSR model of soil reflection spectrum and the inverse-log spectra, the test samples' average of relative error is 16% and 17% respectively, the correlation coefficient between retrieval value and measured value is 0.84 and 0.91 respectively, for it's faster to estimate the soil organic fraction.

[Analysis of directional characteristics of winter wheat canopy spectra].

The bidirectional reflectance factors vary as the incidence directions and the view angles change. At present the remote sensing is almost at nadir, therefore it is possible to improve the accuracy of remote sensing application by reasonably selecting the looking angle, solar zenith angle, and so on. Based on the multidirectional spectra of winter wheat canopy at several critical growth stages, the paper quantitatively analyzed the sensitivity of narrowband bidirectional reflectance to view planes, view zenith angle, solar zenith angle, growth stage, and band by using anisotropy factor (ANIF) and anisotropy index (ANIX). The change of NDVI with view zenith angle, solar zenith angle and growth stage was also studied. The results show that the anisotropy characteristics of bidirectional reflectance factors at solar principal plane was stronger than that at the other planes, and orthogonal principal plane was the weakest. The ANIX at solar principal plane was the biggest. The reason was that the shadow of canopy changed more dramatically at solar principal plane than at the other planes. The sensitivity of bidirectional reflectance factor at visible bands to zenith angles was stronger than in near infrared regions, the reason for which was that the shadow effect in visible regions was stronger than in near infrared regions. The ANIX in visible regions was bigger than in near infrared regions. The sensitivity of bidirectional reflectance factor to solar zenith angles increased as the view zenith angle increased. The NDVIs at every looking zenith angle all increased with the leaf area index increasing. The NDVIs at forward direction were larger than at backward direction, which resulted from that the shadow effect in visible regions was stronger than in near infrared regions. The solar principal plane implies rich internal structure information on object. In order to reduce the uncertainty from the observing method, the near infrared bands and small solar zenith angle should be chosen. The retrieve of structure parameters ought to select solar principal plane, and avoid hot spot region when inversing biological parameters using NDVI.

Highlights of Antibody Engineering and Therapeutics 2019 in San Diego, USA: Bispecific Antibody Design and Clinical Applications.

Although there are only two bispecific antibody (bsAb) drugs in the market, around 100 bsAb drug candidates are in clinical development. BsAbs have gained fast growing investment and attractions from the biopharmaceutical industry and academia in recent years. Antibody Engineering & Therapeutics 2019 (AET 2019) was held in San Diego, USA, from December 9th to 13th, 2019. This year's AET certainly reflected the trend. In this report, we selected eleven presentations from AET 2019 to highlight bsAbs' design and their potentials in cancer therapy. These presentations have discussed emerging strategies to improve bispecific antibody drugs in efficacy, safety, and production. As compared to CAR-Ts, some T cell-redirecting bsAbs may potentially achieve comparable efficacies with less side effects and toxicities, as evidenced with both preclinical and clinical data reviewed at the conference. Several approaches to reduce T cell engagers' toxicities including conditionally active bsAbs and IgM-based bsAbs were also presented and discussed at the conference. For the first time, The Antibody Society and the Chinese Antibody Society jointly held a special session at the AET.

NANOS: a germline stem cell's Guardian Angel.

NANOS is known to be required for germline cell development in a variety of animal species and for the maintenance of germline stem cells in Drosophila. The recent study by Sada et al. has demonstrated that NANOS2, one of the three mammalian homologues, is required intrinsically for maintaining adult mouse spermatogonial stem cell self-renewal.

PTHrP prevents chondrocyte premature hypertrophy by inducing cyclin-D1-dependent Runx2 and Runx3 phosphorylation, ubiquitylation and proteasomal degradation.

In chondrocytes, PTHrP maintains them in a proliferative state and prevents premature hypertrophy. The mechanism by which PTHrP does this is not fully understood. Both Runx2 and Runx3 are required for chondrocyte maturation. We recently demonstrated that cyclin D1 induces Runx2 protein phosphorylation and degradation. In the present studies, we tested the hypothesis that PTHrP regulates both Runx2 and Runx3 protein stability through cyclin D1. We analyzed the effects of cyclin D1 on Runx3 protein stability and function using COS cells, osteoprogenitor C3H10T1/2 cells and chondrogenic RCJ3.1C5.18 cells. We found that cyclin D1 induced Runx3 degradation in a dose-dependent manner and that both Myc-tagged Runx3 and endogenous Runx3 interact directly with CDK4 in COS and RCJ3.1C5.18 cells. A conserved CDK recognition site was identified in the C-terminal region of Runx3 by sequence analysis (residues 356-359). Pulse-chase experiments showed that the mutation of Runx3 at Ser356 to alanine (SA-Runx3) increased the half-life of Runx3. By contrast, the mutation at the same serine residue to glutamic acid (SE-Runx3) accelerated Runx3 degradation. In addition, SA-Runx3 was resistant to cyclin D1-induced degradation. GST-Runx3 was strongly phosphorylated by CDK4 in vitro. By contrast, CDK4 had no effect on the phosphorylation of SA-Runx3. Although both wild-type and SE-Runx3 were ubiquitylated, this was not the case for SA-Runx3. Runx3 degradation by cyclin D1 was completely blocked by the proteasome inhibitor PS1. In C3H10T1/2 cells, SA-Runx3 had a greater effect on reporter activity than SE-Runx3. The same was true for ALP activity in these cells. To investigate the role of cyclin D1 in chondrocyte proliferation and hypertrophy, we analyzed the growth plate morphology and expression of chondrocyte differentiation marker genes in Ccnd1-knockout mice. The proliferating and hypertrophic zones were significantly reduced and expression of chondrocyte differentiation marker genes and ALP activity were enhanced in 2-week-old Ccnd1-knockout mice. PTHrP significantly suppressed protein levels of both Runx2 and Runx3 in primary chondrocytes derived from wild-type mice. By contrast, the suppressive effect of PTHrP on Runx2 and Runx3 protein levels was completely abolished in primary chondrocytes derived from Ccnd1-knockout mice. Our findings demonstrate that the cell cycle proteins cyclin D1 and CDK4 induce Runx2 and Runx3 phosphorylation, ubiquitylation and proteasomal degradation. PTHrP suppresses Runx2 and Runx3 protein levels in chondrocytes through cyclin D1. These results suggest that PTHrP might prevent premature hypertrophy in chondrocytes, at least in part by inducing degradation of Runx2 and Runx3 in a cyclin-D1-dependent manner.

Bone morphogenetic protein 2 activates Smad6 gene transcription through bone-specific transcription factor Runx2.

BMP-2 plays an essential role in osteoblast and chondrocyte differentiation, but its signaling mechanism has not been fully defined. In the present studies, we investigated the mechanism through which BMP-2 activates the Smad6 gene. A -2006/+45 Smad6 promoter-luciferase construct was generated along with deletions and Runx2 binding site mutations to examine the role of Smad1 and Runx2 signaling following BMP-2 stimulation in osteoblasts. Transfection of Runx2 or treatment with BMP-2-stimulated promoter activity of the -2006/+45 and -1191/+45 reporters but not the -829/+45 and -374/+45 reporters. No Smad1/5 binding site is present in the -1191/-829 region of the Smad6 promoter. Mutation of the OSE2-a site (-1036/-1031) completely abolished the stimulatory effect of Runx2 as well as BMP-2 on the -2006/+45 and -1191/+45 Smad6 reporters. Gel shift and chromatin immunoprecipitation (ChIP) assays showed that Runx2 binds the OSE2-a element. ChIP assays demonstrated that Smad1 also interacts with the OSE2-a site at the Smad6 promoter through Runx2. The protein degradation of Runx2 is mediated by the E3 ubiquitin ligase Smurf1. In the present studies, we found that Smurf1 binds the OSE2-a site through Runx2 and inhibits Smad6 gene transcription. Treatment with BMP-2 and transfection of Smad1 abolished Smurf1 binding to the OSE2 site. These results show that Smad1 binding excludes Smurf1 interaction with the OSE2 site and promotes Smad6 gene transcription.

Cyclin D1-cdk4 induce runx2 ubiquitination and degradation.

Runx2 is a Runt domain transcription factor involved in the activation of genes encoding osteoblast and chondrocyte-specific proteins. Runx2 activity is regulated by transcriptional and post-transcriptional mechanisms. The functional significance of the post-translational modification of Runx2 has not been fully defined. We show that cyclin D1-Cdk4 induce Runx2 degradation in an ubiquitination-proteasome-dependent manner. Mutagenesis of Runx2 serine-472, a consensus Cdk site, to alanine increases the half-life of Runx2 and causes loss of sensitivity to cyclin D1-induced Runx2 degradation. The targeted Runx2 degradation by cyclin D1 identifies a novel mechanism through which Runx2 activity is regulated coordinately with the cell cycle machinery in bone cells.

Smad6 interacts with Runx2 and mediates Smad ubiquitin regulatory factor 1-induced Runx2 degradation.

Runx2 is a bone-specific transcription factor that plays a critical role in bone development, postnatal bone formation, and chondrocyte maturation. The protein levels of Runx2 are regulated by the ubiquitin-proteasome pathway. In previous studies we discovered that E3 ubiquitin ligase Smad ubiquitin regulatory factor 1 (Smurf1) induces Runx2 degradation in a ubiquitin-proteasome-dependent manner, and Smurf1 plays an important role in osteoblast function and bone formation. In the present studies we investigated the molecular mechanism of Smurf1-induced Runx2 degradation. Smurf1 interacts with the PY motif of substrate proteins, and a PY motif has been identified in the C terminus of the Runx2 protein. To determine whether Smurf1 induces Runx2 degradation through the interaction with the PY motif of Runx2, we created a mutant Runx2 with a PY motif deletion and found that Smurf1 retained some of its ability to induce the degradation of the mutant Runx2, suggesting that Smurf1 could induce Runx2 degradation through an indirect mechanism. Smurf1 has been shown to interact with Smads 1, 5, 6, and 7, and Smads 1 and 5 also interact with Runx2. In the present studies we found that Smads 1 and 5 had no effect on Smurf1-induced Runx2 degradation. Although Smads 6 and 7 bind Smurf1, it is not known if Smads 6 or 7 interacts with Runx2 and mediate Runx2 degradation. We performed immunoprecipitation assays and found that Smad6 but not Smad7 interacts with Runx2. Smad6 enhances Smurf1-induced Runx2 degradation in an ubiquitin-proteasome-dependent manner. These results demonstrate that in addition to its interaction with the PY motif of Runx2, Smurf1 induces Runx2 degradation in a Smad6-dependent manner. Smurf1-induced Runx2 degradation serves as a negative regulatory mechanism for the BMP-Smad-Runx2 signaling pathway.