Tumor- and Nerve-Derived Axon Guidance Molecule Promotes Pancreatic Ductal Adenocarcinoma Progression and Metastasis through Macrophage Reprogramming.

Axon guidance molecules were found to be the gene family most frequently altered in pancreatic ductal adenocarcinoma (PDA) through mutations and copy number changes. However, the exact molecular mechanism regarding PDA development remained unclear. Using genetically engineered mouse models to examine one of the axon guidance molecules, semaphorin 3D (SEMA3D), we found a dual role for tumor-derived SEMA3D in malignant transformation of pancreatic epithelial cells and a role for nerve-derived SEMA3D in PDA development. This was demonstrated by the pancreatic-specific knockout of the SEMA3D gene from the KRAS G12D and TP53 R 172 H mutation knock-in, PDX1-Cre (KPC) mouse model which demonstrated a delayed tumor initiation and growth comparing to the original KPC mouse model. Our results showed that SEMA3D knockout skews the macrophages in the pancreas away from M2 polarization, providing a potential mechanistic role of tumor-derived SEMA3D in PDA development. The KPC mice with the SEMA3D knockout remained metastasis-free, however, died from primary tumor growth. We then tested the hypothesis that a potential compensation mechanism could result from SEMA3D which is naturally expressed by the intratumoral nerves. Our study further revealed that nerve-derived SEMA3D does not reprogram macrophages directly, but reprograms macrophages indirectly through ARF6 signaling and lactate production in PDA tumor cells. SEMA3D increases tumor-secreted lactate which is sensed by GPCR132 on macrophages and subsequently stimulates pro-tumorigenic M2 polarization in vivo. Tumor intrinsic- and extrinsic-SEMA3D induced ARF6 signaling through its receptor Plexin D1 in a mutant KRAS-dependent manner. Consistently, RNA sequencing database analysis revealed an association of higher KRAS MUT expression with an increase in SEMA3D and ARF6 expression in human PDAs. Moreover, multiplex immunohistochemistry analysis showed an increased number of M2-polarized macrophages proximal to nerves in human PDA tissue expressing SEMA3D. Thus, this study suggests altered expression of SEMA3D in tumor cells lead to acquisition of cancer-promoting functions and the axon guidance signaling originating from nerves is "hijacked" by tumor cells to support their growth. Other axon guidance and neuronal development molecules may play a similar dual role which is worth further investigation. One sentence summary: Tumor- and nerve-derived SEMA3D promotes tumor progression and metastasis through macrophage reprogramming in the tumor microenvironment. STATEMENT OF SIGNIFICANCE: This study established the dual role of axon guidance molecule, SEMA3D, in the malignant transformation of pancreatic epithelial cells and of nerve-derived SEMA3D in PDA progression and metastasis. It revealed macrophage reprogramming as the mechanism underlying bothroles. Together, this research elucidated how inflammatory responses promote invasive PDA progression and metastasis through an oncogenic process.

Anthropometric characteristics and physical activity level of Orienteers: a pilot study / Características antropométricas e nível de atividade física de Orientistas: um estudo piloto

Abstract The present study aimed to describe a study protocol for Orienteers' anthropometric characteristics and physical activity level. This is an individualized, observation and cross-sectional pilot study, that has encompassed three Orienteers (2 Portuguese men and 1 Spanish woman) with mean age 22.6 ± 3.78 years and 8.0 ± 2.64 consecutive years of Orientation practice. In total, 26 anthropometric variables were assessed: four basic measurements, nine skinfolds, nine girths and four breadths; Body Mass Index was calculated, as well as body composition and somatotype (according to the Heath-Carter method). The International Physical Activity Questionnaire - Short Form was used to obtain the score expressed as metabolic equivalent and the energy expenditure in kilocalories, both during the reference week. Mean somatotype recorded for Orienteering athletes could be defined as balanced mesomorph. Scores recorded for different physical activity/ inactivity expressed domains have shown high-energy expenditure. Sports Science Professionals can use the herein proposed protocol to improve Orienteers' training.

Resumo Objetivou-se descrever um protocolo de estudo das características antropométricas e do nível de atividade física de Orientistas. Trata-se de um estudo piloto, caracterizado como individualizado, observacional e transversal. Participaram do estudo três Orientistas (2 homens Portugueses e 1 mulher Espanhola) com 22,6 ± 3,78 anos de idade e 8,0 ± 2,64 anos de prática consecutiva de Orientação. Foram avaliadas 26 variáveis antropométricas: quatro medidas básicas, nove dobras cutâneas, nove circunferências e quatro diâmetros ósseos; Índice de Massa Corporal foi calculado, bem como a composição corporal e o somatotipo (de acordo com o método Heath-Carter). O Questionário Internacional de Atividade Física, versão curta e auto-administrado, foi utilizado para obter a pontuação expressa como equivalente metabólico e o dispêndio energético em quilocalorias, ambos durante a semana de referência. A média do somatotipo dos atletas de Orientação pode ser definida como mesomorfo balanceado. As pontuações dos diferentes domínios da atividade física/ inatividade expressas, demonstraram um elevado dispêndio energético. Profissionais das Ciências do Esporte podem usar o protocolo proposto para melhor controle do treinamento de Orientistas.

Redox properties and PAS domain structure of the Escherichia coli energy sensor Aer indicate a multistate sensing mechanism.

The Per-Arnt-Sim (PAS; named for the representative proteins: Period, Aryl hydrocarbon receptor nuclear translocator protein and Single-minded) domain of the dimeric Escherichia coli aerotaxis receptor Aer monitors cellular respiration through a redox-sensitive flavin adenine dinucleotide (FAD) cofactor. Conformational shifts in the PAS domain instigated by the oxidized FAD (FADOX)/FAD anionic semiquinone (FADASQ) redox couple traverse the HAMP (histidine kinases, adenylate cyclases, methyl-accepting chemotaxis proteins, and phosphatases) and kinase control domains of the Aer dimer to regulate CheA kinase activity. The PAS domain of Aer is unstable and has not been previously purified. Here, residue substitutions that rescue FAD binding in an FAD binding-deficient full-length Aer variant were used in combination to stabilize the Aer PAS domain. We solved the 2.4 Å resolution crystal structure of this variant, Aer-PAS-GVV, and revealed a PAS fold that contains distinct features associated with FAD-based redox sensing, such as a close contact between the Arg115 side chain and N5 of the isoalloxazine ring and interactions of the flavin with the side chains of His53 and Asn85 that are poised to convey conformational signals from the cofactor to the protein surface. In addition, we determined the FADox/FADASQ formal potentials of Aer-PAS-GVV and full-length Aer reconstituted into nanodiscs. The Aer redox couple is remarkably low at -289.6 ± 0.4 mV. In conclusion, we propose a model for Aer energy sensing based on the low potential of Aer-PAS-FADox/FADASQ couple and the inability of Aer-PAS to bind to the fully reduced FAD hydroquinone.

Efecto del tratamiento preventivo básico sobre la microflora salival en niños. Recuento de Streptococcus mutans / Effect of basic preventive treatment on salivary microflora in children. Count of Streptococcus mutans

Recuentos de Streptococcus mutans superiores a 10.000 ó 20.000 UF/ml. de saliva indican riesgo biológico de contraer caries. Por ello, cuando se realiza un tratamiento odontológico preventivo, que tiene por finalidad reducir el riesgo cariogénico, las determinaciones del número de Streptococcus mutans en saliva deberían servir para su evaluación. Por esta razón, el objetivo de este trabajo fue: 1. Establecer el efecto que tiene el tratamiento preventivo básico sobre el recuento de Streptococcus mutans y 2. Determinar cómo influye el mismo sobre la microflora salival. Los resultados indican que: 1. Este tipo de atención odontológica disminuye significativamente el recuento de Streptococcus mutans en saliva en el grupo de niños estudiado, 2. El tratamiento no modifica la microflora salival Gram positiva pero influye disminuyendo significativamente los cocos y bacilos Gram negativos y las espiroquetas. El tratamiento odontológico preventivo realizado en este trabajo disminuye no sólo el riesgo cariogénico sino también el periodontopático contribuyendo a conservar la salud dentaria y gingival