Role of PDGFRA+ cells and a CD55+ PDGFRALo fraction in the gastric mesenchymal niche.

PDGFRA-expressing mesenchyme supports intestinal stem cells. Stomach epithelia have related niche dependencies, but their enabling mesenchymal cell populations are unknown, in part because previous studies pooled the gastric antrum and corpus. Our high-resolution imaging, transcriptional profiling, and organoid assays identify regional subpopulations and supportive capacities of purified mouse corpus and antral PDGFRA+ cells. Sub-epithelial PDGFRAHi myofibroblasts are principal sources of BMP ligands and two molecularly distinct pools distribute asymmetrically along antral glands but together fail to support epithelial growth in vitro. In contrast, PDGFRALo CD55+ cells strategically positioned beneath gastric glands promote epithelial expansion in the absence of other cells or factors. This population encompasses a small fraction expressing the BMP antagonist Grem1. Although Grem1+ cell ablation in vivo impairs intestinal stem cells, gastric stem cells are spared, implying that CD55+ cell activity in epithelial self-renewal derives from other subpopulations. Our findings shed light on spatial, molecular, and functional organization of gastric mesenchyme and the spectrum of signaling sources for epithelial support.

Drug rash with eosinophilia and systemic symptoms (DRESS) syndrome in childhood: a narrative review.

Despite being rare, the Drug Rash with Eosinophilia and Systemic Symptoms (DRESS) syndrome is a serious, possibly fatal condition that may affect both adults and children who may be also burdened by delayed sequelae. It is an adverse drug reaction characterized by widespread skin involvement, fever, lymphadenopathy, visceral involvement, and laboratory abnormalities (eosinophilia, mononucleosis-like atypical lymphocytes). It is more frequently triggered by anticonvulsants, sulphonamides, or antibiotics, the latter being responsible for up to 30% of pediatric cases. The disease typically develops 2-8 weeks after exposure to the culprit medication, with fever and widespread skin eruption; mild viral prodromes are possible. Unfortunately, diagnosis is challenging due to the absence of a reliable test; however, a score by the European Registry of Severe Cutaneous Adverse Reactions (RegiSCAR) allows to classify suspect patients into no, possible, probable, or definite DRESS cases. Moreover, rapid-onset DRESS syndrome has been described in recent years. It affects children more often than adults and differs from the most common form because it appears ≤15 days vs. >15 days after starting the drug, it is usually triggered by antibiotics or iodinated contrast media rather than by anticonvulsants and has a higher presence of lymphadenopathy. Differential diagnosis between rapid-onset antibiotic-driven DRESS syndrome, viral exanthems, or other drug eruptions may be challenging, but it is mandatory to define it as early as possible to start adequate treatment and monitor possible complications. The present review reports the latest evidence about the diagnosis and treatment of pediatric DRESS syndrome.

Exposure to outdoor air pollution and risk of hospitalization for bronchiolitis in an urban environment: A 9-year observational study.

BACKGROUND: Outdoor air pollution is supposed to influence the course of bronchiolitis, but the evidence is limited. The present study aimed at evaluating the role of outdoor air pollutants on hospitalization for bronchiolitis. METHODS: Infants aged ≤12 months referred for bronchiolitis to our Pediatric Emergency Department in Bologna, Italy, from 1 October 2011 to 16 March 2020 (nine epidemic seasons) were retrospectively included. Daily concentrations of benzene (C6 H6 ), nitrogen dioxide (NO2 ), particulate matter ≤2.5 µm (PM2.5 ), and ≤10 µm (PM10 ), and the mean values of individual patient exposure in the week and the 4 weeks before hospital access were calculated. The association between air pollutants exposure and hospitalization was evaluated through logistic regression analysis. RESULTS: A total of 2902 patients were enrolled (59.9% males; 38.7% hospitalized). Exposure to PM2.5 in the 4 weeks preceding bronchiolitis was identified as the main parameter significantly driving the risk of hospitalization (odds ratio [95% confidence interval]: 1.055 [1.010-1.102]). After stratifying by season, higher values of other outdoor air pollutants were found to significantly affect hospitalization: 4-week exposure to C6 H6 (Season 2011-2012, 4.090 [1.184-14.130]) and PM2.5 (Season 2017-2018, 1.282 [1.032-1.593]), and 1-week exposure to C6 H6 (Season 2012-2013, 6.193 [1.552-24.710]), NO2 (Season 2013-2014, 1.064 [1.009-1.122]), PM2.5 (Season 2013-2014, 1.080 [1.023-1.141]), and PM10 (Season 2018-2019, 1.102 [0.991-1.225]). CONCLUSION: High levels of PM2.5 , C6 H6 , NO2 , and PM10 may increase the risk of hospitalization in children affected by bronchiolitis. Open-air exposure of infants during rush hours and in the most polluted areas should be avoided.

Different Pediatric Acute Care Settings Influence Bronchiolitis Management: A 10-Year Retrospective Study.

Bronchiolitis is the main cause of hospitalization in infants. Diagnosis is clinical, and treatment is based on hydration and oxygen therapy. Nevertheless, unnecessary diagnostic tests and pharmacological treatments are still very common. This retrospective study aimed to evaluate whether the setting of bronchiolitis care influences diagnostic and therapeutic choices. The management of 3201 infants, referred to our Italian Tertiary Care Center for bronchiolitis between 2010 and 2020, was analyzed by comparing children discharged from the pediatric emergency department (PEDd group) undergoing short-stay observation (SSO group) and hospitalization. Antibiotic use in PEDd, SSO, and ward was 59.3% vs. 51.6% vs. 49.7%, respectively (p < 0.001); inhaled salbutamol was mainly administered in PEDd and during SSO (76.1% and 82.2% vs. 38.3% in ward; p < 0.001); the use of corticosteroids was higher during SSO and hospitalization (59.6% and 49.1% vs. 39.0% in PEDd; p < 0.001); inhaled adrenaline was administered mostly in hospitalized infants (53.5% vs. 2.5% in SSO and 0.2% in PEDd; p < 0.001); chest X-ray use in PEDd, SSO, and ward was 30.3% vs. 49.0% vs. 70.5%, respectively (p < 0.001). In a multivariate analysis, undergoing SSO was found to be an independent risk factor for the use of systemic corticosteroid and salbutamol; being discharged at home was found to be a risk factor for antibiotic prescription; undergoing SSO and hospitalization resulted as independent risk factors for the use of CXR. Our study highlights that different pediatric acute care settings could influence the management of bronchiolitis. Factors influencing practice may include a high turnover of PED medical staff, personal reassurance, and parental pressure.

Outdoor Air Pollution and Childhood Respiratory Disease: The Role of Oxidative Stress.

The leading mechanisms through which air pollutants exert their damaging effects are the promotion of oxidative stress, the induction of an inflammatory response, and the deregulation of the immune system by reducing its ability to limit infectious agents' spreading. This influence starts in the prenatal age and continues during childhood, the most susceptible period of life, due to a lower efficiency of oxidative damage detoxification, a higher metabolic and breathing rate, and enhanced oxygen consumption per unit of body mass. Air pollution is involved in acute disorders like asthma exacerbations and upper and lower respiratory infections, including bronchiolitis, tuberculosis, and pneumoniae. Pollutants can also contribute to the onset of chronic asthma, and they can lead to a deficit in lung function and growth, long-term respiratory damage, and eventually chronic respiratory illness. Air pollution abatement policies, applied in the last decades, are contributing to mitigating air quality issues, but more efforts should be encouraged to improve acute childhood respiratory disease with possible positive long-term effects on lung function. This narrative review aims to summarize the most recent studies on the links between air pollution and childhood respiratory illness.

Defining the structure, signals, and cellular elements of the gastric mesenchymal niche.

PDGFRA-expressing mesenchyme provides a niche for intestinal stem cells. Corresponding compartments are unknown in the stomach, where corpus and antral glandular epithelia have similar niche dependencies but are structurally distinct from the intestine and from each other. Previous studies considered antrum and corpus as a whole and did not assess niche functions. Using high-resolution imaging and sequencing, we identify regional subpopulations and niche properties of purified mouse corpus and antral PDGFRA + cells. PDGFRA Hi sub-epithelial myofibroblasts are principal sources of BMP ligands in both gastric segments; two molecularly distinct groups distribute asymmetrically along antral glands but together fail to support epithelial organoids in vitro . In contrast, strategically positioned PDGFRA Lo cells that express CD55 enable corpus and antral organoid growth in the absence of other cellular or soluble factors. Our study provides detailed insights into spatial, molecular, and functional organization of gastric mesenchyme and the spectrum of signaling sources for stem cell support.

A 10-Year Retrospective Study on Pediatric Visceral Leishmaniasis in a European Endemic Area: Diagnostic and Short-Course Therapeutic Strategies.

BACKGROUND: Visceral leishmaniasis (VL) is a potentially fatal disease, with an increasing occurrence in northern Italy, affecting children and both immunocompetent and immunocompromised adults. METHODS: This retrospective study conducted at the St. Orsola University Hospital of Bologna, Italy, evaluates the characteristics of 16 children (with a median age of 14.3 months) who were hospitalized between 2013 and 2022 for VL. RESULTS: Seventy-five percent of patients presented with a triad of fever, cytopenia, and splenomegaly. An abdominal ultrasound examination revealed splenomegaly and hypoechoic spleen abnormalities in 93.8% and 73.3% of cases, respectively. Five VL cases were complicated by secondary hemophagocytic lymphohistiocytosis. Eleven patients were treated with a single 10 mg/kg dose of Liposomal Amphotericin B (L-AmB), while five received two doses (total of 20 mg/kg); one of the former groups experienced a recurrence. The fever generally decreased 48 h after the first L-AmB dose, and hemoglobin levels normalized within a month. The splenomegaly resolved in approximately 4.5 months. CONCLUSIONS: Pediatricians should consider VL in children with fever of an unknown origin, anemia, cytopenia, and splenomegaly. In our experience, abdominal ultrasounds and molecular tests on peripheral blood contributed to diagnosis without the need for bone marrow aspiration. The short-course therapy with two 10 mg/kg doses of L-AmB is safe and effective.

MKK6 deficiency promotes cardiac dysfunction through MKK3-p38γ/δ-mTOR hyperactivation.

Stress-activated p38 kinases control a plethora of functions, and their dysregulation has been linked to the development of steatosis, obesity, immune disorders, and cancer. Therefore, they have been identified as potential targets for novel therapeutic strategies. There are four p38 family members (p38α, p38ß, p38γ, and p38δ) that are activated by MKK3 and MKK6. Here, we demonstrate that lack of MKK6 reduces the lifespan in mice. Longitudinal study of cardiac function in MKK6 KO mice showed that young mice develop cardiac hypertrophy which progresses to cardiac dilatation and fibrosis with age. Mechanistically, lack of MKK6 blunts p38α activation while causing MKK3-p38γ/δ hyperphosphorylation and increased mammalian target of rapamycin (mTOR) signaling, resulting in cardiac hypertrophy. Cardiac hypertrophy in MKK6 KO mice is reverted by knocking out either p38γ or p38δ or by inhibiting the mTOR pathway with rapamycin. In conclusion, we have identified a key role for the MKK3/6-p38γ/δ pathway in the development of cardiac hypertrophy, which has important implications for the clinical use of p38α inhibitors in the long-term treatment since they might result in cardiotoxicity.

The human heart can increase its size to supply more blood to the body's organs. This process, called hypertrophy, can happen during exercise or be caused by medical conditions, such as high blood pressure or inherited genetic diseases. If hypertrophy is continually driven by illness, this can cause the heart to fail and no longer be able to properly pump blood around the body. For hypertrophy to happen, several molecular changes occur in the cells responsible for contracting the heart, including activation of the p38 pathway. Within this pathway is a p38 enzyme as well as a series of other proteins which are sequentially turned on in response to stress, such as inflammatory molecules or mechanical forces that alter the cell's shape. There are different types of p38 enzyme which have been linked to other diseases, making them a promising target for drug development. However, clinical trials blocking individual members of the p38 family have had disappointing results. An alternative approach is to target other proteins involved in the p38 pathway, such as MKK6, but it is not known what effect this might have. To investigate, Romero-Becerra et al. genetically modified mice to not have any MKK6 protein. As a result, these mice had a shorter lifespan, with hypertrophy developing at a young age that led to heart problems. Romero-Becerra et al. used different mice models to understand why this happened, showing that a lack of MKK6 reduces the activity of a specific member of the p38 family called p38α. However, this blockage boosted a different branch of the pathway which involved two other p38 proteins, p38γ and p38δ. This, in turn, triggered another key pathway called mTOR which also promotes hypertrophy of the heart. These results suggest that drugs blocking MKK6 and p38α could lead to side effects that cause further harm to the heart. A more promising approach for treating hypertrophic heart conditions could be to inhibit p38γ and/or p38δ. However, before this can be fully explored, further work is needed to generate compounds that specifically target these proteins.

Sexual and Reproductive Health and Education of Adolescents during COVID-19 Pandemic, Results from "Come Te La Passi?"-Survey in Bologna, Italy.

Social distancing measures adopted to face the COVID-19 pandemic had a detrimental impact on adolescent education and their interaction with peers and adults, secondary to the limitation of school and recreational activities, with repercussions on social and sexual life. The "Come te la passi?" ("How is it going?") study, performed in the Metropolitan City of Bologna (Italy), aimed at investigating the type of information sources adopted by adolescents for their sexual and reproductive health (SRH) knowledge and education, the age of their sexual debut, and the way in which the COVID-19 pandemic affected their relationships and sexual life in order to help local health care professionals and educators designing SRH education programs. A purposely designed online survey was administered during the COVID-19 pandemic to 378 high school students (age > 14 yo) in July 2021. Based on the study results, the most common source of SRH education was the web, followed by peers (friends). A total of 61.3% of 17-year-olds already had sexual intercourse, and 90% of 15-year-olds had experienced romantic or sexual attraction. For 58.2% of the adolescents, the COVID-19 pandemic had negative effects on their relationships/sexual life. The current research emphasizes the need to involve health care professionals and educators in structured programs to promote SRH education tailored to adolescents' needs and started from early ages.

JNK-mediated disruption of bile acid homeostasis promotes intrahepatic cholangiocarcinoma.

Metabolic stress causes activation of the cJun NH2-terminal kinase (JNK) signal transduction pathway. It is established that one consequence of JNK activation is the development of insulin resistance and hepatic steatosis through inhibition of the transcription factor PPARα. Indeed, JNK1/2 deficiency in hepatocytes protects against the development of steatosis, suggesting that JNK inhibition represents a possible treatment for this disease. However, the long-term consequences of JNK inhibition have not been evaluated. Here we demonstrate that hepatic JNK controls bile acid production. We found that hepatic JNK deficiency alters cholesterol metabolism and bile acid synthesis, conjugation, and transport, resulting in cholestasis, increased cholangiocyte proliferation, and intrahepatic cholangiocarcinoma. Gene ablation studies confirmed that PPARα mediated these effects of JNK in hepatocytes. This analysis highlights potential consequences of long-term use of JNK inhibitors for the treatment of metabolic syndrome.

Distinct Mesenchymal Cell Populations Generate the Essential Intestinal BMP Signaling Gradient.

Intestinal stem cells (ISCs) are confined to crypt bottoms and their progeny differentiate near crypt-villus junctions. Wnt and bone morphogenic protein (BMP) gradients drive this polarity, and colorectal cancer fundamentally reflects disruption of this homeostatic signaling. However, sub-epithelial sources of crucial agonists and antagonists that organize this BMP gradient remain obscure. Here, we couple whole-mount high-resolution microscopy with ensemble and single-cell RNA sequencing (RNA-seq) to identify three distinct PDGFRA+ mesenchymal cell types. PDGFRA(hi) telocytes are especially abundant at the villus base and provide a BMP reservoir, and we identified a CD81+ PDGFRA(lo) population present just below crypts that secretes the BMP antagonist Gremlin1. These cells, referred to as trophocytes, are sufficient to expand ISCs in vitro without additional trophic support and contribute to ISC maintenance in vivo. This study reveals intestinal mesenchymal structure at fine anatomic, molecular, and functional detail and the cellular basis for a signaling gradient necessary for tissue self-renewal.

Replicational Dilution of H3K27me3 in Mammalian Cells and the Role of Poised Promoters.

Polycomb repressive complex 2 (PRC2) places H3K27me3 at developmental genes and is causally implicated in keeping bivalent genes silent. It is unclear if that silence requires minimum H3K27me3 levels and how the mark transmits faithfully across mammalian somatic cell generations. Mouse intestinal cells lacking EZH2 methyltransferase reduce H3K27me3 proportionately at all PRC2 target sites, but ∼40% uniform residual levels keep target genes inactive. These genes, derepressed in PRC2-null villus cells, remain silent in intestinal stem cells (ISCs). Quantitative chromatin immunoprecipitation and computational modeling indicate that because unmodified histones dilute H3K27me3 by 50% each time DNA replicates, PRC2-deficient ISCs initially retain sufficient H3K27me3 to avoid gene derepression. EZH2 mutant human lymphoma cells also require multiple divisions before H3K27me3 dilution relieves gene silencing. In both cell types, promoters with high basal H3K4me2/3 activate in spite of some residual H3K27me3, compared to less-poised promoters. These findings have implications for PRC2 inhibition in cancer therapy.

p38γ is essential for cell cycle progression and liver tumorigenesis.

The cell cycle is a tightly regulated process that is controlled by the conserved cyclin-dependent kinase (CDK)-cyclin protein complex1. However, control of the G0-to-G1 transition is not completely understood. Here we demonstrate that p38 MAPK gamma (p38γ) acts as a CDK-like kinase and thus cooperates with CDKs, regulating entry into the cell cycle. p38γ shares high sequence homology, inhibition sensitivity and substrate specificity with CDK family members. In mouse hepatocytes, p38γ induces proliferation after partial hepatectomy by promoting the phosphorylation of retinoblastoma tumour suppressor protein at known CDK target residues. Lack of p38γ or treatment with the p38γ inhibitor pirfenidone protects against the chemically induced formation of liver tumours. Furthermore, biopsies of human hepatocellular carcinoma show high expression of p38γ, suggesting that p38γ could be a therapeutic target in the treatment of this disease.

Adiponectin accounts for gender differences in hepatocellular carcinoma incidence.

Hepatocellular carcinoma (HCC) is the sixth most common cancer type and the fourth leading cause of cancer-related death. This cancer appears with higher incidence in men and during obesity; however, the specific mechanisms underlying this correlation are unknown. Adipose tissue, a key organ in metabolic syndrome, shows evident gender disparities in the production of adipokines. Levels of the important adipokine adiponectin decrease in men during puberty, as well as in the obese state. Here, we show that this decrease in adiponectin levels is responsible for the increased liver cancer risk in males. We found that testosterone activates the protein JNK in mouse and human adipocytes. JNK-mediated inhibition of adiponectin secretion increases liver cancer cell proliferation, since adiponectin protects against liver cancer development through the activation of AMP-activated protein kinase (AMPK) and p38α. This study provides insight into adipose tissue to liver crosstalk and its gender relation during cancer development, having the potential to guide strategies for new cancer therapeutics.

MKK6 controls T3-mediated browning of white adipose tissue.

Increasing the thermogenic capacity of adipose tissue to enhance organismal energy expenditure is considered a promising therapeutic strategy to combat obesity. Here, we report that expression of the p38 MAPK activator MKK6 is elevated in white adipose tissue of obese individuals. Using knockout animals and shRNA, we show that Mkk6 deletion increases energy expenditure and thermogenic capacity of white adipose tissue, protecting mice against diet-induced obesity and the development of diabetes. Deletion of Mkk6 increases T3-stimulated UCP1 expression in adipocytes, thereby increasing their thermogenic capacity. Mechanistically, we demonstrate that, in white adipose tissue, p38 is activated by an alternative pathway involving AMPK, TAK, and TAB. Our results identify MKK6 in adipocytes as a potential therapeutic target to reduce obesity.Brown and beige adipose tissues dissipate heat via uncoupling protein 1 (UCP1). Here the authors show that the stress activated kinase MKK6 acts as a repressor of UCP1 expression, suggesting that its inhibition promotes adipose tissue browning and increases organismal energy expenditure.

Stress kinases in the modulation of metabolism and energy balance.

Obesity is a new global pandemic, with growing incidence and prevalence. This disease is associated with increased risk of several pathologies, including diabetes, cardiovascular diseases, and cancer. The mechanisms underlying obesity-associated metabolic changes are the focus of efforts to identify new therapies. Stress-activated protein kinases (SAPK), including cJun N-terminal kinases (JNKs) and p38, are required for cellular responses to metabolic stress and therefore might contribute to the pathogenesis of obesity. Tissue-specific knockout models support a cell-type-specific role for JNK isoforms, in particular JNK1, highlighting its importance in cell homeostasis and organ crosstalk. However, more efforts are needed to elucidate the specific roles of other JNK isoforms and p38 family members in metabolism and obesity. This review provides an overview of the role of SAPKs in the regulation of metabolism.

Eukaryotic elongation factor 2 controls TNF-α translation in LPS-induced hepatitis.

Bacterial LPS (endotoxin) has been implicated in the pathogenesis of acute liver disease through its induction of the proinflammatory cytokine TNF-α. TNF-α is a key determinant of the outcome in a well-established mouse model of acute liver failure during septic shock. One possible mechanism for regulating TNF-α expression is through the control of protein elongation during translation, which would allow rapid cell adaptation to physiological changes. However, the regulation of translational elongation is poorly understood. We found that expression of p38γ/δ MAPK proteins is required for the elongation of nascent TNF-α protein in macrophages. The MKK3/6-p38γ/δ pathway mediated an inhibitory phosphorylation of eukaryotic elongation factor 2 (eEF2) kinase, which in turn promoted eEF2 activation (dephosphorylation) and subsequent TNF-α elongation. These results identify a new signaling pathway that regulates TNF-α production in LPS-induced liver damage and suggest potential cell-specific therapeutic targets for liver diseases in which TNF-α production is involved.

Dissection of the RET/ß-catenin interaction in the TPC1 thyroid cancer cell line.

The RET receptor tyrosine kinase is a member of the cadherin superfamily and plays a pivotal role in cell survival, differentiation and proliferation. Currently, 12 ret/ptc chimeric oncogenes, characterized by the fusion between the intracellular domain of RET and different activating genes, which can cause ligand-independent dimerization and constitutive activation, have been described. ß-catenin is usually involved in the maintenance of cell-to-cell adhesion and mediates the Wnt/ß-catenin pathway important during embryogenesis and in cellular malignant transformation. Recently, a novel mechanism of RET-mediated function through the ß-catenin pathway has been reported in multiple endocrine neoplasia type 2 and in sporadic thyroid carcinomas. Here, we investigated the effects of the ZD6474, a small molecule RET-inhibitor, on RET/ß-catenin interaction. We confirmed the ZD6474 mediated-inhibition of recombinant RET kinase and of growth of cells expressing RET/PTC. Interestingly, we firstly observed reduced cellular mobility and changed morphology of TPC1 treated cells suggesting that RET-inhibitor could affect ß-catenin cellular distribution as resulted in its co-immunoprecipitation with E-cadherin. We further investigated this hypothesis showing that TPC1 treated cells displayed predominantly ß-catenin cytosolic localization. Surprisingly, RET and ß-catenin co-immunoprecipitated in both ZD6474-treated and untreated TPC1 cells, suggesting that RET/ß-catenin interaction might not be affected by RET kinase inactivation. All together these results suggest that RET kinase activation is crucial for ß-catenin stabilization (pY654), localization and its signaling pathway activation but not for ß-catenin/RET physical interactions, in human papillary thyroid carcinomas. In conclusion, ZD6474, by inhibiting RET kinase, down-modulates ß-catenin pathway leading its recruitment to the membrane by E-cadherin.