Causal effects of diabetic retinopathy on depression, anxiety and bipolar disorder in the European population: a Mendelian randomization study

PURPOSE

To verify the causal effects of diabetic retinopathy (DR) on depression, anxiety and bipolar disorder (BD).

METHODS

Mendelian randomization (MR) analysis was performed to identify the causal relationships between DR and depression or anxiety or BD via using DR-related GWAS data (14,584 cases and 176,010 controls), depression-related GWAS data (59,851 cases and 113,154 controls), anxiety-related GWAS data (7016 cases and 14,745 controls) and BD-related GWAS data (41,917 cases and 371,549 controls). The inverse-variance weighted (IVW) model was adopted to estimate the causal relationship. The outcome was expressed as odds ratio (OR) with 95% confidence intervals (CI).

RESULTS

The MR analysis results presented that DR was causally associated with a significantly increased risk of BD in the European population (IVW, OR = 1.06, 95%CI [1.03, 1.08], P = 2.44 × 10-6), while DR was unable to causally influence the risk of depression (IVW, OR = 1.01, 95%CI [0.99, 1.04], P = 0.32) and anxiety (IVW, OR = 0.97, 95%CI [0.89, 1.06], P = 0.48) in the European population. Subgroup analysis based on BD identified DR causally increased the risk of bipolar I disorder (BD I) but not bipolar II disorder (BD II). Sensitivity analysis results did not show any pleiotropy and heterogeneity in both groups of analyses, indicating that the results were stable and reliable.

CONCLUSIONS

The results of the current MR analysis indicated a causal relationship between DR and BD in the European population, while there was no causal connection between DR and depression or anxiety. However, further research is needed to confirm these conclusions.

[Effectiveness analysis of hybrid endoscopic submucosal dissection in patients with colorectal epithelium-derived tumors]

Objective: To compare the clinical benefits of classic endoscopic submucosal dissection (ESD) and hybrid ESD for the treatment of colorectal epithelium-derived tumors. Methods: The current investigation was a retrospective multicenter study of 418 patients who underwent ESD between January 2015 and April 2021 at Beijing Jishuitan Hospital. The patients were assigned to one of two groups based on the surgical procedure they underwent; a classic ESD group or a hybrid ESD group. The primary outcome was the rate of en bloc resection and complete resection. SPSS 26.0 was used for statistical analysis. Homogeneity of variance was assessed via Cochran's test. Normally distributed data with homogeneity of variance were analyzed via the t-test for independent samples. Non-normally distributed data and data with unequal variance were analyzed via the Kruskal-Wallis non-parametric test. Categorical data were analyzed via the Chi-square test or Fisher's exact test. Multivariable assessment was performed via logistic regression analysis. Results: The en bloc resection rates [89.4% (84/94) vs. 87.0% (194/223), χ2=0.34, P=0.558] and complete resection rates [85.1% (80/94) vs. 82.1% (183/223), χ2=0.33, P=0.510] were similar. Compared with classic ESD, procedures were shorter in the hybrid ESD group [22(7, 213) vs. 47(12, 680) min, Z=0.23, P<0.001], dissection was completed more rapidly [0.14(0.02, 0.32) vs. 0.10(0.02, 0.41) cm2/min, Z=0.08, P<0.001], and there was a higher rate of perforation (9.6% vs. 2.2%, χ2=2.67, P=0.006). Laterally spreading tumor granular type nodular mixed, non-granular type pseudo-depressed, flat-elevated type (odds ratio 2.826, P=0.012), and tumor location (odds ratio 6.970, P=0.005) were independently associated with complete resection in the hybrid ESD group. Conclusion: Classic ESD and hybrid ESD had similar en bloc and complete resection rates for colorectal epithelium-derived tumors, but hybrid ESD had shorter operation times. With respect to hybrid ESD, factors associated with failure of complete resection included lesion type and crossing tissue boundaries.

Lycium barbarum glycopeptide alleviates neuroinflammation in spinal cord injury via modulating docosahexaenoic acid to inhibiting MAPKs/NF-kB and pyroptosis pathways

BACKGROUND

Lycium barbarum polysaccharide (LBP) is an active ingredient extracted from Lycium barbarum that inhibits neuroinflammation, and Lycium barbarum glycopeptide (LbGp) is a glycoprotein with immunological activity that was purified and isolated from LBP. Previous studies have shown that LbGp can regulate the immune microenvironment, but its specific mechanism of action remains unclear.

AIMS

In this study, we aimed to explore the mechanism of action of LbGp in the treatment of spinal cord injury through metabolomics and molecular experiments.

METHODS

SD male rats were randomly assigned to three experimental groups, and after establishing the spinal cord hemisection model, LbGp was administered orally. Spinal cord tissue was sampled on the seventh day after surgery for molecular and metabolomic experiments. In vitro, LbGp was administered to mimic the inflammatory microenvironment by activating microglia, and its mechanism of action in suppressing neuroinflammation was further elaborated using metabolomics and molecular biology techniques such as western blotting and q-PCR.

RESULTS

In vivo and in vitro experiments found that LbGp can improve the inflammatory microenvironment by inhibiting the NF-kB and pyroptosis pathways. Furthermore, LbGp induced the secretion of docosahexaenoic acid (DHA) by microglia, and DHA inhibited neuroinflammation through the MAPK/NF-κB and pyroptosis pathways.

CONCLUSIONS

In summary, we hypothesize that LbGp improves the inflammatory microenvironment by regulating the secretion of DHA by microglia and thereby inhibiting the MAPK/NF-κB and pyroptosis pathways and promoting nerve repair and motor function recovery. This study provides a new direction for the treatment of spinal cord injury and elucidates the potential mechanism of action of LbGp.

A 2-Stage Root Analog Implant with Compact Structure, Uniform Roughness, and High Accuracy

Immediate implant placement has the advantages of shortening the operation time, reducing the treatment cycle and cost. At present, this technology has been used widely, but the indications of immediate implantation are still limited. Here, a novel type of root analog implant (RAI) was manufactured by selective laser melting technology to address the limitation. Under optimized condition, RAIs were printed with the internal density of 99.73% and the uniform surface roughness of 11 μm (Sa). Besides, the deviation between RAI specimen and design models is controlled within 0.15 mm after optimizing scanning parameters. The substrate printed could promote human bone marrow stromal cell proliferation, spreading, and osteogenic differentiation. The bone-implant contact (BIC, 75% ± 7%) and bone volume/total volume (BV/TV, 74% ± 7%) of RAIs were significantly higher than that of conventional implants (BIC, 66% ± 5%; BV/TV, 62% ± 5%) in in vivo experiments. Further, customized abutments were designed for the RAIs, improving the masticatory ability of the beagle dogs after crown restoration. This study aims to design a personalized 2-stage RAI with compact structure and uniform roughness, in order to achieve better fracture resistance, initial osseointegration efficiency, and dispersed stress in immediate implantation. It provides a certain guiding value for standardizing the manufacture and clinical application of RAI in immediate implantation.

Integrated transcriptomic and metabolomic profiling reveals dysregulation of purine metabolism during the acute phase of spinal cord injury in rats

Introduction

Spinal cord injury (SCI) results in drastic dysregulation of microenvironmental metabolism during the acute phase, which greatly affects neural recovery. A better insight into the potential molecular pathways of metabolic dysregulation by multi-omics analysis could help to reveal targets that promote nerve repair and regeneration in the future.

Materials and methods

We established the SCI model and rats were randomly divided into two groups: the acute-phase SCI (ASCI) group (n = 14, 3 days post-SCI) and the sham group with day-matched periods (n = 14, without SCI). In each group, rats were sacrificed at 3 days post-surgery for histology study (n = 3), metabolome sequencing (n = 5), transcriptome sequencing (n = 3), and quantitative real-time polymerase chain reaction (n = 3). The motor function of rats was evaluated by double-blind Basso, Beattie, and Bresnahan (BBB) Locomotor Scores at 0, 1, 2, 3 days post-SCI in an open field area. Then the transcriptomic and metabolomic data were integrated in SCI model of rat to reveal the underlying molecular pathways of microenvironmental metabolic dysregulation.

Results

The histology of the microenvironment was significantly altered in ASCI and the locomotor function was significantly reduced in rats. Metabolomics analysis showed that 360 metabolites were highly altered during the acute phase of SCI, of which 310 were up-regulated and 50 were down-regulated, and bioinformatics analysis revealed that these differential metabolites were mainly enriched in arginine and proline metabolism, D-glutamine and D-glutamate metabolism, purine metabolism, biosynthesis of unsaturated fatty acids. Transcriptomics results showed that 5,963 genes were clearly altered, of which 2,848 genes were up-regulated and 3,115 genes were down-regulated, and these differentially expressed genes were mainly involved in response to stimulus, metabolic process, immune system process. Surprisingly, the Integrative analysis revealed significant dysregulation of purine metabolism at both transcriptome and metabolome levels in the acute phase of SCI, with 48 differential genes and 16 differential metabolites involved. Further analysis indicated that dysregulation of purine metabolism could seriously affect the energy metabolism of the injured microenvironment and increase oxidative stress as well as other responses detrimental to nerve repair and regeneration.

Discussion

On the whole, we have for the first time combined transcriptomics and metabolomics to systematically analyze the potential molecular pathways of metabolic dysregulation in the acute phase of SCI, which will contribute to broaden our understanding of the sophisticated molecular mechanisms of SCI, in parallel with serving as a foundation for future studies of neural repair and regeneration after SCI.

[Mechanism of nerve growth factor promotes angiogenesis and skeletal muscle fiber remodeling in a mouse hindlimb ischemic model]

Objective: To explore the mechanism of nerve growth factor (NGF) in the skeletal muscle fiber remodeling in ischemic limbs during therapeutic angiogenesis. Methods: Eighteen female mice with SPF grade, 6 weeks old and 25-30 g weighed were randomly allocated to sham-operated group (n=6), blank control group (n=6) and NGF gene transfection group (n=6). The left hindlimb ischemia models were established by ligating the femoral artery in blank control group and NGF gene transfection group. Seven days after the operation, mice in the three groups were separately injected with normal saline, empty plasmids, and NGF plasmids. Gastrocnemius of left hindlimbs was harvested after the blood perfusion assessment of the ischemic limb on the 21st postoperative day. The gastrocnemius muscle specimens were stained with HE, CD31 and proliferating cell nuclear antigen (PCNA) immunohistochemistry staining, the mRNA expressions of myosin heavy chain-Ⅰ(MHC-Ⅰ), MHC-Ⅱa and MHC-Ⅱb were measured by real-time PCR, and the protein level of NGF and peroxisome proliferator-activated receptors-β/δ (PPAR β/δ) were detected by Western blot. The expression of cytochrome C oxidase (COX), isocitrate dehydrogenase (IDH) and adenosine triphosphate (ATP) were examined by enzyme-linked immunosorbent assay (ELISA). Results: On the 21st day after operation, the blood perfusion of the ischemic limb in NGF gene transfection group was (195.70±9.99)PU, which was lower than that in sham-operated group (312.15±17.32)PU (P=0.001), while it was higher than that in blank control group (82.11±8.55)PU (P=0.001). The degree of muscle atrophy in the NGF gene transfection group was lower than that in the blank control group. The capillary density of NGF gene transfection group (0.34±0.05) was higher than that of sham-operated group (0.11±0.03) and blank control group (0.27±0.04) (P<0.05). The endothelial cell proliferation index in NGF gene transfection group (0.39±0.19) was significantly higher than that in sham-operated group (0.18±0.01) and blank control group (0.25±0.14) (P<0.05). The expression of NGF, PPAR β/δ, COX, IDH, ATP, and MHC-Ⅰ mRNA in NGF gene transfection group were significantly higher than those in sham-operated group and blank control group (P<0.05). Conclusions: NGF gene transfection can promote angiogenesis in the ischemic limbs of mice, increase the blood perfusion, and thus induce the remodeling of skeletal muscle fibers to type Ⅰ. This process may be related to NGF-induced PPAR β/δ expression and promote the cellular aerobic metabolism in skeletal muscle.

MSX1 Drives Tooth Morphogenesis Through Controlling Wnt Signaling Activity

Tooth agenesis is a common structural birth defect in humans that results from failure of morphogenesis during early tooth development. The homeobox transcription factor Msx1 and the canonical Wnt signaling pathway are essential for "bud to cap" morphogenesis and are causal factors for tooth agenesis. Our recent study suggested that Msx1 regulates Wnt signaling during early tooth development by suppressing the expression of Dkk2 and Sfrp2 in the tooth bud mesenchyme, and it demonstrated partial rescue of Msx1-deficient molar teeth by a combination of DKK inhibition and genetic inactivation of SFRPs. In this study, we found that Sostdc1/Wise, another secreted Wnt antagonist, is involved in regulating the odontogenic pathway downstream of Msx1. Whereas Sostdc1 expression in the developing tooth germ was not increased in Msx1-/- embryos, genetic inactivation of Sostdc1 rescued maxillary molar, but not mandibular molar, morphogenesis in Msx1-/- mice with full penetrance. Since the Msx1-/-;Sostdc1-/- embryos exhibited ectopic Dkk2 expression in the developing dental mesenchyme, similar to Msx1-/- embryos, we generated and analyzed tooth development in Msx1-/-;Dkk2-/- double and Msx1-/-;Dkk2-/-;Sostdc1-/- triple mutant mice. The Msx1-/-;Dkk2-/- double mutants showed rescued maxillary molar morphogenesis at high penetrance, with a small percentage also exhibiting mandibular molars that transitioned to the cap stage. Furthermore, tooth development was rescued in the maxillary and mandibular molars, with full penetrance, in the Msx1-/-;Dkk2-/-;Sostdc1-/- mice. Together, these data reveal 1) that a key role of Msx1 in driving tooth development through the bud-to-cap transition is to control the expression of Dkk2 and 2) that modulation of Wnt signaling activity by Dkk2 and Sostdc1 plays a crucial role in the Msx1-dependent odontogenic pathway during early tooth morphogenesis.

Circadian Period 2 (Per2) downregulate inhibitor of differentiation 3 (Id3) expression via PTEN/AKT/Smad5 axis to inhibits glioma cell proliferation

In this study, we employed multiple laboratory techniques to acknowledge the biological activities and processes of Per2 and Id3 in glioma. We analyzed TCGA and CGGA databases for seeking association among Per2, Id3, and clinical features in glioma. Immunohistochemistry and Western blot were used to detect protein expression levels. CCK-8 assay, colony formation assay, Transwell assay, the wound healing assay, flow cytometric, and Xenograft nude mice were used to acknowledge the impact of Per2 and Id3 on biological behavior of glioma. The results showed that the Per2 mRNA expression was negatively correlated with the WHO grade, while the Id3 mRNA expression was positively correlated with the WHO grade in patients with glioma in TCGA and CGGA databases. Per2 and Id3 maintained separate prognostic abilities and had a negative connection in human glioma. In the clinical sample study, Per2 and Id3 were validated at the protein level with the same results compared to the mRNA expression level in TCGA and CGGA. By using a wide range of functional examples, overexpression of Per2 restrains malignant biological behaviors in glioma cells by many ways, while Id3 promotes malignant biological behaviors in glioma cells. Furthermore, overexpression of Per2 can inhibit Id3 expression via regulating PTEN/AKT/Smad5 signaling pathway and thereby abolish malignant biological behaviors that are caused by Id3 overexpression. These results suggested that Per2 inhibits glioma cell proliferation through regulating PTEN/AKT/Smad5/Id3 signaling pathway, which may be a viable therapeutic target for glioma.

Effects of nitrogen supply rate on photosynthesis, nitrogen uptake and growth of seedlings in a Eucalyptus/Dalbergia odorifera intercropping system

The introduction of N₂ -fixing species into a Eucalyptus plantation resulted in a successful planting system. It is essential to understand the contribution of nitrogen (N) competition and photosynthetic efficiency to plant dry matter yield to shed more light on the growth mechanism of the Eucalyptus/legume system. We compared N competition, photosynthesis and dry matter yield of Eucalyptus urophylla × E. grandis and the N₂ -fixing tree species Dalbergia odorifera in intercropping and monoculture systems under different N levels. The photosynthesis of E. urophylla × E. grandis was improved, while that of D. odorifera was inhibited in the intercropping system. Intercropped E. urophylla × E. grandis increased the N utilization and the dry matter yield by 6.57-48.46% and 7.59-97.26%, and decreased those of D. odorifera by 10.21-30.33% and 0.48-13.19%, respectively. Furthermore, N application enhanced the competitive ability of E. urophylla × E. grandis relative to D. odorifera and changed the N contents and chlorophyll synthesis to optimize the photosynthetic structure of both species. Our results reveal Eucalyptus for photosynthesis, N absorption and increasing the growth benefit from the introduction of N₂ -fixing species, which hence can be considered to be an effective sustainable management option of Eucalyptus plantations.

CT texture analysis-based nomogram for the preoperative prediction of visceral pleural invasion in cT1N0M0 lung adenocarcinoma: an external validation cohort study

AIM

To develop a nomogram based on computed tomography (CT) texture analysis for the preoperative prediction of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma.

MATERIALS AND METHODS

A dataset of chest CT containing lung nodules was collected from two institutions, and all surgically resected nodules were classified pathologically based on the presence of visceral pleural invasion. Each nodule on the CT image was segmented automatically by artificial-intelligence software and its CT texture features were extracted. The dataset was divided into training and external validation cohorts according to the institution, and a nomogram for predicting visceral pleural invasion was developed and validated.

RESULTS

Of a total of 313 patients enrolled from two independent institutions, 63 were diagnosed with visceral pleural invasion. Three-dimensional (3D) CT long diameter, skewness, and sphericity, and chronic obstructive pulmonary disease were identified as independent predictors for visceral pleural invasion by multivariable logistic regression. The nomogram based on multivariable logistic regression showed great discriminative ability, as indicated by a C-index of 0.890 (95% confidence interval [CI]: 0.867-0.914) and 0.864 (95% CI: 0.817-0.911) for the training and external validation cohorts, respectively. Additionally, calibration of the nomogram revealed good predictive ability, as indicated by the Brier score (0.108 and 0.100 for the training and external validation cohorts, respectively).

CONCLUSIONS

A nomogram was developed that could compute the probability of visceral pleural invasion in patients with cT1N0M0 lung adenocarcinoma with good calibration and discrimination. The nomogram has potential as a reliable tool for clinical evaluation and decision-making.

Stoichioproteomics study of differentially expressed proteins and pathways in head and neck cancer

Hypoxia is a prominent feature of head and neck cancer. However, the oxygen element characteristics of proteins and how they adapt to hypoxia microenvironments of head and neck cancer are still unknown. Human genome sequences and proteins expressed data of head and neck cancer were retrieved from pathology atlas of Human Protein Atlas project. Then compared the oxygen and carbon element contents between proteomes of head and neck cancer and normal oral mucosa-squamous epithelial cells, genome locations, pathways, and functional dissection associated with head and neck cancer were also studied. A total of 902 differentially expressed proteins were observed where the average oxygen content is higher than that of the lowly expressed proteins in head and neck cancer proteins. Further, the average oxygen content of the up regulated proteins was 2.54% higher than other. None of their coding genes were distributed on the Y chromosome. The up regulated proteins were enriched in endocytosis, apoptosis and regulation of actin cytoskeleton. The increased oxygen contents of the highly expressed and the up regulated proteins might be caused by frequent activity of cytoskeleton and adapted to the rapid growth and fast division of the head and neck cancer cells. The oxygen usage bias and key proteins may help us to understand the mechanisms behind head and neck cancer in targeted therapy, which lays a foundation for the application of stoichioproteomics in targeted therapy and provides promise for potential treatments for head and neck cancer.

[Long-term therapeutic effects and liver fibrosis changes with direct-antiviral therapy in HIV/HCV co-infected patients]

Objective: To investigate the long-term characteristic changes of virus, immune status, and liver fibrosis markers in human immunodeficiency virus (HIV)/hepatitis C virus (HCV) co-infected patients after receiving direct-antiviral agents (DAAs). Methods: HIV/HCV co-infected patients who visited the Guangzhou Eighth People's Hospital, Guangzhou Medical University from May 2014 to December 2019 were selected as the research subjects. The changes of virological response rate, peripheral blood CD4(+)T lymphocyte level and serological markers of liver fibrosis (APRI score and FIB-4 index) were observed during 144 weeks of follow-up course after the end of DAAs treatment. Kruskal-Wallis test was used for statistical approach. Results: A total of 103 cases were included in the study. There were 87 males (87.5%), with a median age of 44 years. Sustained virological response rate at 12 weeks (SVR12) after DAAs treatment was 97.6%, and the SVR during the entire follow-up period was at least 95.9%. Compared with baseline, CD4(+)T lymphocyte count were significantly increased equally at 12 weeks (Z = -2.283, P = 0.022), 24 weeks (Z = -3.538, P < 0.001), 48 weeks (Z = -3.297, P = 0.001), 96 weeks (Z = -3.562, P < 0.001), and 144 weeks (Z = -2.842, P = 0.004). APRI score (Z = -6.394, P < 0.001) and FIB-4 index (Z = -2.528, P = 0.011) were significantly lower than baseline at week 4 of DAAs treatment, and thereafter remained at a low level, without further declination. Conclusion: HIV/HCV co-infected patients can maintain high SVR for a long time, acquire good immune reconstitution, and significantly improve liver fibrosis after DAAs treatment.

COSMOS next generation - A public knowledge base leveraging chemical and biological data to support the regulatory assessment of chemicals

The COSMOS Database (DB) was originally established to provide reliable data for cosmetics-related chemicals within the COSMOS Project funded as part of the SEURAT-1 Research Initiative. The database has subsequently been maintained and developed further into COSMOS Next Generation (NG), a combination of database and in silico tools, essential components of a knowledge base. COSMOS DB provided a cosmetics inventory as well as other regulatory inventories, accompanied by assessment results and in vitro and in vivo toxicity data. In addition to data content curation, much effort was dedicated to data governance - data authorisation, characterisation of quality, documentation of meta information, and control of data use. Through this effort, COSMOS DB was able to merge and fuse data of various types from different sources. Building on the previous effort, the COSMOS Minimum Inclusion (MINIS) criteria for a toxicity database were further expanded to quantify the reliability of studies. COSMOS NG features multiple fingerprints for analysing structure similarity, and new tools to calculate molecular properties and screen chemicals with endpoint-related public profilers, such as DNA and protein binders, liver alerts and genotoxic alerts. The publicly available COSMOS NG enables users to compile information and execute analyses such as category formation and read-across. This paper provides a step-by-step guided workflow for a simple read-across case, starting from a target structure and culminating in an estimation of a NOAEL confidence interval. Given its strong technical foundation, inclusion of quality-reviewed data, and provision of tools designed to facilitate communication between users, COSMOS NG is a first step towards building a toxicological knowledge hub leveraging many public data systems for chemical safety evaluation. We continue to monitor the feedback from the user community at support@mn-am.com.

Krüppel-like factor 6 promotes odontoblastic differentiation through regulating the expression of dentine sialophosphoprotein and dentine matrix protein 1 genes

AIM

To investigate the potential role of Krüppel-like factor 6 (KLF6) in the odontoblastic differentiation of immortalized dental papilla mesenchymal cells (iMDP-3) cells.

METHODOLOGY

Alizarin Red S (ARS) and Alkaline phosphatase (ALP) staining was used to examine the mineralization effect of iMDP-3 cells after odontoblastic induction. Real-time PCR and Western blotting were employed to analyse dentine sialophosphoprotein (DSPP), dentine matrix protein 1 (DMP1), RUNX family transcription factor 2 (RUNX2), ALP and KLF6 expression during this process. Co-expression of the KLF6 with DMP1, DSPP and RUNX2 was detected by double immunofluorescence staining to explore their local relationship in the cell. To further investigate KLF6 functions, Klf6 gain- and loss-of-function assays followed by ARS and ALP stainings, real-time PCR and Western blotting were performed using Klf6-overexpression plasmids and Klf6 siRNA to investigate whether changes in Klf6 expression affect the odontoblastic differentiation of iMDP-3 cells. Dual-luciferase reporter assays were used to elucidate the mechanistic regulation of Dspp and Dmp1 expression by Klf6. Means were compared using the unpaired t-test and Kruskal-Wallis one-way anova with P < 0.05 and P < 0.01 defined as statistical significance levels.

RESULTS

The expression levels of Klf6 (P < 0.01), Dspp (P < 0.05), Dmp1 (P < 0.01), Runx2 (P < 0.01) and Alp (P < 0.01) were significantly elevated during odontoblastic differentiation of iMDP-3 cells. KLF6 was co-localized with DSPP, DMP1 and RUNX2 in the cytoplasm and nucleus of iMDP-3 cells. Overexpression of Klf6 promoted the odontoblastic differentiation of iMDP-3, whereas the inhibition of Klf6 prevented this procession. Dual-luciferase assays revealed that Klf6 upregulates Dspp and Dmp1 transcription in iMDP-3 cells during odontoblastic differentiation.

CONCLUSION

Klf6 promoted odontoblastic differentiation by targeting the transcription promoter of Dmp1 and Dspp. This study may offer novel insights into strategies for treating injuries to dental pulp tissue.

Opsin 5 is a key regulator of ultraviolet radiation-induced melanogenesis in human epidermal melanocytes

Background

Human skin, which is constantly exposed to solar ultraviolet radiation (UVR), has a unique ability to respond by increasing its pigmentation in a protective process driven by melanogenesis in human epidermal melanocytes (HEMs). However, the molecular mechanisms used by HEMs to detect and respond to UVR remain unclear.

Objectives

To investigate the function and potential mechanism of opsin 5 (OPN5), a photoreceptor responsive to UVR wavelengths, in melanogenesis in HEMs.

Methods

Melanin content in HEMs was determined using the NaOH method, and activity of tyrosinase (TYR) (a key enzyme in melanin synthesis) was determined by the l‐DOPA method. OPN5 expression in UVR‐treated vs. untreated HEMs and explant tissues was detected by reverse‐transcription quantitative polymerase chain reaction (RT‐qPCR), Western blotting and immunofluorescence. Short interfering RNA‐mediated OPN5 knockdown and a lentivirus OPN5 overexpression model were used to examine their respective effects on TYR, tyrosinase‐related protein 1 (TRP1), TRP2 and microphthalmia‐associated transcription factor (MITF) expression, under UVR. Changes in expression of TYR, TRP1 and TRP2 caused by changes in OPN5 expression level were detected by RT‐qPCR and Western blot. Furthermore, changes in signalling pathway proteins were assayed.

Results

We found that OPN5 is the key sensor in HEMs responsible for UVR‐induced melanogenesis. OPN5‐induced melanogenesis required Ca²⁺‐dependent G protein‐coupled receptor‐ and protein kinase C signal transduction, thus contributing to the UVR‐induced MITF response to mediate downstream cellular effects, and providing evidence of OPN5 function in mammalian phototransduction. Remarkably, OPN5 activation was necessary for UVR‐induced increase in cellular melanin and has an inherent function in melanocyte melanogenesis.

Conclusions

Our results provide insight into the molecular mechanisms of UVR sensing and phototransduction in melanocytes, and may reveal molecular targets for preventing pigmentation or pigment diseases.

What is already known about this topic?

Ultraviolet radiation (UVR) induces a protective response to DNA damage mediated by melanin synthesis in human epidermal melanocytes (HEMs).

Tyrosinase (TYR), with tyrosinase‐related proteins (TRP1, TRP2), are the key enzymes for melanin synthesis.

Microphthalmia‐associated transcription factor regulates key genes for melanocyte development and differentiation, and can stimulate melanogenesis by activating transcription of TYR and other pigmentation genes, including TRP1.

Opsin 5 (OPN5) is known to function as a photoreceptor responsive to wavelengths in the near UV spectrum.

What does this study add?

UVR induces melanogenesis in HEMs via OPN5.

OPN5 regulates expression of TYR, TRP1 and TRP2 through the calcium‐dependent G protein‐coupled and protein kinase C signalling pathways.

OPN5 has an inherent role in HEMs in mediating melanogenesis.

What is the translational message?

OPN5 was discovered as a key sensor for UVR‐induced melanogenesis in human skin melanocytes.

It could be a target for early treatment of pigmentation or pigment diseases, to provide a more personalized and economically feasible method.

Linked Comment: L.V.M. de Assis and A.M. de Lauro Castrucci. Br J Dermatol 2021; 185:249–250.

Plain language summary available online

Measurement of the Spectral Shape of the β-Decay of ^{137}Xe to the Ground State of ^{137}Cs in EXO-200 and Comparison with Theory

We report on a comparison between the theoretically predicted and experimentally measured spectra of the first-forbidden nonunique β-decay transition ^{137}Xe(7/2^{-})→^{137}Cs(7/2^{+}). The experimental data were acquired by the EXO-200 experiment during a deployment of an AmBe neutron source. The ultralow background environment of EXO-200, together with dedicated source deployment and analysis procedures, allowed for collection of a pure sample of the decays, with an estimated signal to background ratio of more than 99 to 1 in the energy range from 1075 to 4175 keV. In addition to providing a rare and accurate measurement of the first-forbidden nonunique β-decay shape, this work constitutes a novel test of the calculated electron spectral shapes in the context of the reactor antineutrino anomaly and spectral bump.

Genome-wide Identification of Foxf2 Target Genes in Palate Development

Cleft palate is among the most common structural birth defects in humans. Previous studies have shown that mutations in FOXF2 are associated with cleft palate in humans and mice and that Foxf2 acts in a Shh-Foxf-Fgf18-Shh molecular network controlling palatal shelf growth. In this study, we combined RNA-seq and ChIP-seq approaches to identify direct transcriptional target genes mediating Foxf2 function in palate development in mice. Of 155 genes that exhibited Foxf2-dependent expression in the developing palatal mesenchyme, 88 contained or were located next to Foxf2-binding sites. Through in situ hybridization analyses, we demonstrate that expression of many of these target genes, including multiple genes encoding transcription factors and several encoding extracellular matrix-modifying proteins, were specifically upregulated in the posterior region of palatal shelves in Foxf2^-/- mouse embryos. Foxf2 occupancy at many of these putative target loci, including Fgf18, in the developing palatal tissues was verified by ChIP-polymerase chain reaction analyses. One of the Foxf2 target genes, Chst2, encodes a carbohydrate sulfotransferase integral to glycosaminoglycan sulfation. Correlating with ectopic Chst2 expression, Foxf2^-/- embryos a exhibited region-specific increase in sulfated keratan sulfate and a concomitant reduction in chondroitin sulfate accumulation in the posterior palatal mesenchyme. However, expression of the core protein of versican, a major chondroitin sulfate proteoglycan important in palatal shelf morphogenesis, was increased, whereas expression of collagen I was reduced in the corresponding region of the palatal mesenchyme. These results indicate that, in addition to regulating palatal shelf growth through the Fgf18-Shh signaling network, Foxf2 controls palatal shelf morphogenesis through regulating expression of multiple transcription factors as well as through directly controlling the synthesis and processing of extracellular matrix components in the palatal mesenchyme. Our ChIP-seq and RNA-seq data sets provide an excellent resource for comprehensive understanding of the molecular network controlling palate development.