Genetic reduction of cilium length by targeting intraflagellar transport 88 protein impedes kidney and liver cyst formation in mouse models of autosomal polycystic kidney disease.

Polycystin-1 (PC1) and -2 (PC2), products of the PKD1 and PKD2 genes, are mutated in autosomal dominant polycystic kidney disease (ADPKD). They localize to the primary cilia; however, their ciliary function is in dispute. Loss of either the primary cilia or PC1 or PC2 causes cyst formation. However, loss of both cilia and PC1 or PC2 inhibits cyst growth via an unknown pathway. To help define a pathway, we studied cilium length in human and mouse kidneys. We found cilia are elongated in kidneys from patients with ADPKD and from both Pkd1 and Pkd2 knockout mice. Cilia elongate following polycystin inactivation. The role of intraflagellar transport proteins in Pkd1-deficient mice is also unknown. We found that inactivation of Ift88 (a gene expressing a core component of intraflagellar transport) in Pkd1 knockout mice, as well as in a new Pkd2 knockout mouse, shortened the elongated cilia, impeded kidney and liver cystogenesis, and reduced cell proliferation. Multi-stage in vivo analysis of signaling pathways revealed ß-catenin activation as a prominent, early, and sustained event in disease onset and progression in Pkd2 single knockout but not in Pkd2.Ift88 double knockout mouse kidneys. Additionally, AMPK, mTOR and ERK pathways were altered in Pkd2 single knockout mice but only AMPK and mTOR pathway alteration were rescued in Pkd2.Ift88 double knockout mice. Thus, our findings advocate an essential role of polycystins in the structure and function of the primary cilia and implicate ß-catenin as a key inducer of cystogenesis downstream of the primary cilia. Our data suggest that modulating cilium length and/or its associated signaling events may offer novel therapeutic approaches for ADPKD.

Gα12 is required for renal cystogenesis induced by Pkd1 inactivation.

Mutation of PKD1, encoding the protein polycystin-1 (PC1), is the main cause of autosomal dominant polycystic kidney disease (ADPKD). The signaling pathways downstream of PC1 in ADPKD are still not fully understood. Here, we provide genetic evidence for the necessity of Gα12 (encoded by Gna12, hereafter Gα12) for renal cystogenesis induced by Pkd1 knockout. There was no phenotype in mice with deletion of Gα12 (Gα12-/-). Polyinosine-polycytosine (pI:pC)-induced deletion of Pkd1 (Mx1Cre+Pkd1f/fGα12+/+) in 1-week-old mice resulted in multiple kidney cysts by 9 weeks, but the mice with double knockout of Pkd1 and Gα12 (Mx1Cre+Pkd1f/fGα12-/-) had no structural and functional abnormalities in the kidneys. These mice could survive more than one year without kidney abnormalities except multiple hepatic cysts in some mice, which indicates that the effect of Gα12 on cystogenesis is kidney specific. Furthermore, Pkd1 knockout promoted Gα12 activation, which subsequently decreased cell-matrix and cell-cell adhesion by affecting the function of focal adhesion and E-cadherin, respectively. Our results demonstrate that Gα12 is required for the development of kidney cysts induced by Pkd1 mutation in mouse ADPKD.

Two-component protein hydrogels assembled using an engineered disulfide-forming protein-ligand pair.

We present the development of a two-component self-assembling protein hydrogel. The building blocks of the hydrogel are two liquid-phase protein block copolymers each containing (1) a subunit of the trimeric protein CutA as a cross-linker and (2) one member of a PDZ-domain-containing protein-ligand pair whose interaction was reinforced by an engineered disulfide linkage. Mixing of the two building blocks reconstitutes a self-assembling polypeptide unit, triggering hydrogel formation. This hydrogel exhibits extremely high solution stability at neutral and acidic pHs and in a wide range of temperatures (4-50 °C). Incorporation of a "docking station peptide" binding motif into a hydrogel building block enables functionalization of the hydrogel with target proteins tagged with a "docking protein". We demonstrated the application of an enzyme-functionalized hydrogel in a direct electron transfer enzymatic biocathode. These disulfide-reinforced protein hydrogels provide a potential new material for diverse applications including industrial biocatalysis, biosynthesis, biofuels, tissue engineering, and controlled drug delivery.

Pressure-induced stromal keratopathy after laser in situ keratomileusis: Acute and late-onset presentations.

We present a series of 4 cases of pressure-induced stromal keratopathy after laser in situ keratomileusis (LASIK). Four patients (5 eyes) with previous LASIK presented for poor visual acuity and ocular pain because of ocular hypertension. At examination, all cases revealed corneal haze and a space filled with fluid between the surgical flap and the residual stroma. All cases were managed with topical hypotensive treatment and one of them was also treated with a valve drainage device. Topical steroids restriction was indicated in all cases. Intraocular pressure (IOP) was normalized in all cases with subsequent interface fluid resolution and significant improvement of vision in most cases. Early recognition and appropriate treatment for pressure-induced stromal keratopathy is essential to avoid complications associated with prolonged elevated IOP. It is extremely important to measure the IOP in the peripheral cornea because IOP in the central cornea can be incorrectly measured with the characteristic interface fluid developed in this entity.

Total mercury exposure risk and selenium content measuring on fishery products consumed by women of childbearing age from Bogota, Colombia / Riesgo de exposición a mercurio total y medición del contenido de selenio en productos de la pesca consumidos por mujeres en edad fértil de Bogotá, Colombia

Background: Dietary exposure to mercury in women of childbearing age could result in neurological effects on the fetus. A health risk assessment of total mercury by fishery products intake has not been conducted in this population group in Bogota, Colombia. On the other hand, it has been suggested that selenium content on fishery products may have a protective effect against mercury toxicity. Nevertheless, selenium content on fish species marketed in Bogota has not been determined. Objective: Exposure risk to total mercury and selenium content on fishery products consumed by women of childbearing age from Bogota, Colombia, were assessed. Methods: Total mercury and selenium concentrations for products available at fish stores and supermarkets were determined. The exposure risk to total mercury was estimated considering the intake of these products by women of childbearing age group. Results: Total mercury highest concentrations were 0.8166 mg/kg in mota (Calophysusmacropterus), and 0.6275 mg/kg in catfish (Pseudoplatystoma tigrinum). On the other hand, the highest selenium concentration was 0.6471 mg/kg in nicuro (Pimelodus blochii). Finally, it was established that for women of childbearing age group, health risk of exposure to total mercury due to mota intake exceeded by 8.56-fold the reference dose. Conclusions:Mota intake considerably increases exposure risk to total mercury on women of childbearing age from Bogota, Colombia. The selenium levels established in the fishery products assessed, except for catfish and mota, are theoretically suggestive of a protective effect of selenium against mercury toxicity. Consequently, continuous total mercury concentrations monitoring is required to protect health of women of childbearing age and the general population from Bogota, Colombia

Antecedentes: La exposición dietética al mercurio en mujeres en edad fértil podría provocar efectos neurológicos en el feto. En Bogotá, Colombia no se han realizado evaluaciones de riesgo por la exposición al mercurio total debido a la ingesta de productos de la pesca en este grupo de la población. Por otro lado, ha sido sugerido que el contenido de selenio en los productos de la pesca podría tener un efecto protector frente a la toxicidad por mercurio, sin embargo, el contenido de selenio en las especies de peces comercializadas en Bogotá, Colombia no ha sido determinado. Objetivo: Evaluar el riesgo de exposición al mercurio total y el contenido de selenio en los productos de la pesca consumidos por las mujeres en edad fértil de Bogotá, Colombia. Métodos: Se determinaron las concentraciones de mercurio total y selenio en distintos productos de la pesca disponibles en pescaderías y supermercados. El riesgo de exposición a mercurio total se estimó considerando la ingesta de estos productos por parte de un grupo de mujeres en edad fértil. Resultados: Las concentraciones más altas de mercurio total fueron de 0.8166 mg/kg en mota (Calophysus macropterus) y 0.6275 mg/kg en bagre (Pseudoplatystoma tigrinum). Por otro lado, la concentración más alta de selenio fue de 0.6471 mg/kg en nicuro (Pimelodus blochii). Finalmente, se estableció que el riesgo de exposición a mercurio total, debido a la ingesta de mota, excedió en 8.56 veces la dosis de referencia en el grupo de mujeres en edad fértil. Conclusiones: La ingesta de mota aumenta el riesgo de exposición al mercurio total en las mujeres en edad fértil de Bogotá, Colombia. Por otro lado, los niveles de selenio identificados en los productos evaluados, excepto en bagre y mota, teóricamente sugieren un posible efecto protector del selenio contra la toxicidad por mercurio. Considerando lo indicado, es necesario realizar un monitoreo continuo de las concentraciones de mercurio total en los productos de la pesca, con el fin de proteger la salud de las mujeres en edad fértil y de la población general de Bogotá, Colombia

Complete Resolution of Metastatic Gallbladder Cancer after Standard Gemcitabine-Cisplatin Combination Therapy.

Gallbladder carcinoma (GBC) is a rare and deadly disease. The only curative option is a total surgical resection. If the disease is inoperable, palliative combination chemotherapy with gemcitabine-cisplatin remains the standard of care. We present here a case of a 47-year-old gentleman diagnosed with metastatic GBC who saw a complete resolution of his disease with seven cycles of standard gemcitabine-cisplatin chemotherapy. This case illustrates the importance of multidisciplinary care to explore all available options to provide optimal and tailored patient care.

Nectandra amazonum-derived flavonoids as COX-1 inhibitors: in vitro and docking studies.

The ability of eleven known flavonoids isolated from Nectandra amazonum (Lauraceae) was tested for in vitro PGHS (COX) inhibition. All test compounds exhibited a dose dependent activity at different levels, exhibiting selectivity towards COX-I inhibition. Autodock Vina was used to dock the compound structures within the active site of the PGHS-1 (PDB: 3N8V). In vitro results showed that chalcone and dihydrochalcone-related compounds exhibited reasonable inhibitory properties (IC50: 1.56-36.5 microM), with good correlation with docking results. Argl20 (or Tyr355) and Ser530 were found to be the key residues to dock the most active flavonoids, indicating such interaction might interfere with the formation of prostaglandin H2 in the active site of COX-I.