Porphyria Cutanea Tarda in a 54-Year-Old Patient with a History of Hepatitis C: A Case Report

Background Porphyria CutaneaTarda (PCT) is the most common type of porphyria and is caused by a decrease in the activity of the hepatic enzyme uroporphyrinogen decarboxylase. It is expressed in both a sporadic form and genetic form and typically presents with cutaneous manifestations described as skin blisters in sun exposed areas. Case A 54-year-old male presented complaining of bullous itchy lesions on his hands and upper extremities that were at different stages of healing. Lab results were consistent with porphyria including elevated serum total porphyrins. He was scheduled for phlebotomy every other week for six weeks, hydroxychloroquine, minimize any sun exposure and to completely stop smoking. Conclusion Widespread skin lesions associated with underlying liver disease is a characteristic presentation for PCT. Hepatitis C is an antecedent risk factor for PCT, but can now be treated with antiviral therapy with the expectation of attainment of a sustained virologic response. Improvements in arresting progressive liver disease in Hepatitis C patients may improve PCT symptoms, as well. Keywords: Porphyria CutaneaTarda; Hepatitis C; Acquired liver disease.

Sight-threatening progressive corneo-scleral involvement in porphyria cutanea tarda

Porphyria cutanea tarda is the most common type of porphyria. It is associated with a deficiency of uroporphyrinogen decarboxylase enzyme responsible for heme synthesis. Clinical manifestations are predominantly dermatological and very rarely present with ocular involvement. Although scleral thinning in the interpalpebral area is a well-documented entity, sight-threatening corneal involvement is rarely described. We, herein report a case of a 58-year-old man who presented with ocular surface dryness, photophobia and mild redness. Slit-lamp biomicroscopy revealed corneo-scleral thinning in both eyes. The diagnosis was confirmed with a urine porphyrin test, serum iron and serum ferritin levels. We started him on conservative management after which he was lost to follow-up. He presented again after 6 years with total corneal opacification and progressive loss of vision in the right eye.

Acute Intermittent Porphyria in a Man with Dual Enzyme Deficiencies

Porphyrias are a heterogeneous group of metabolic disorders that result from the altered activity of specific enzymes of the heme biosynthetic pathway and are characterized by accumulation of pathway intermediates. Porphyria cutanea tarda (PCT) is the most common porphyria and is due to deficient activity of uroporphyrinogen decarboxylase (UROD). Acute intermittent porphyria (AIP) is the most common of the acute hepatic porphyrias, caused by decreased activity of hydroxymethylbilane synthase (HMBS). An Argentinean man with a family history of PCT who carried the UROD variant c.10_11insA suffered severe abdominal pain. Biochemical testing was consistent with AIP, and molecular analysis of HMBS revealed a de novo variant: c.344 + 2_ + 5delTAAG. This is one of the few cases of porphyria identified with both UROD and HMBS mutations and the first confirmed case of porphyria with dual enzyme deficiencies in Argentina.

A CRISPR/Cas9 Whole-Genome Screen Identifies Genes Required for Aryl Hydrocarbon Receptor-Dependent Induction of Functional CYP1A1

Environmental pollutants including halogenated aromatic hydrocarbons and polycyclic aromatic hydrocarbons, including benzo[a]pyrene, exert their deleterious effects through the activation of the aryl hydrocarbon receptor (AHR) and by the resulting transcription of genes not yet fully identified. Ligand-bound AHR translocates from cytoplasm to nucleus, where it dimerizes with the aryl hydrocarbon receptor nuclear translocator (ARNT) protein. The AHR/ARNT dimer binds to enhancer regions of responsive genes to activate transcription. AHR also mediates carcinogenesis caused by PAHs, likely via CYP1A1, CYP1A2, and CYP1B1, which are massively induced by activated AHR in many tissues and generate carcinogenic electrophilic derivatives of PAHs. In the current study, we have used the mouse GeCKOv2 genome-wide CRISPR/Cas9 library to identify novel genes in the AHR pathway by taking advantage of a B[a]P selection assay that we previously used to identify core AHR pathway genes in Hepa-1c1c7 murine hepatoma cells. Besides Ahr, Arnt, and Cyp1a1, we report the identification of multiple additional putative AHR pathway genes including several that we validated. These include cytochrome P450 reductase (Por), which mediates redox regeneration of cytochromes P450, and 5 genes of the heme biosynthesis pathway: delta-aminolevulinate synthase 1 (Alas1), porphobilinogen deaminase (Hmbs), uroporphyrinogen decarboxylase (Urod), coproporphyrinogen oxidase (Cpox), and ferrochelatase (Fech): heme being an essential prosthetic group of cytochrome P450 proteins. Notably, several of these genes were identified by GeCKO screening, despite not being identifiable by reverse genetics approaches. This indicates the power of high-sensitivity genome-wide genetic screening for identifying genes in the AHR pathway.

Comparative transcriptome and proteome profiling of the chlorophyll metabolism pathway in four cultivars of Magnolia officinalis

Magnolia officinalis is an important herb in Chinese medicine that has good therapeutic effects on gastrointestinal motility and helps regulate the spleen and stomach. Magnolia officinalis Rehd.et Wils. (abbreviated as CH)、 Magnolia officinalis Rehd.et Wils. var. biloba’ DaAoye’ (abbreviated as DA)、 Magnolia officinalis Rehd.et Wils. var. biloba‘XiaoAoye’ (abbreviated as XA)、Magnolia officinalis Rehd.et Wils. var. biloba‘Liuye’ (abbreviated as LY) are the four main cultivars in Dujiangyan city, Sichuan province in China, and DA has better medicinal effects and higher levels of green pigment than the other three cultivars. Proteomics research not only provides new insights into protein expression patterns but also enables the identification of many attractive candidates for further research on the effects of pesticides on chlorophyll metabolism in Magnolia officinalis. Transcriptome and proteome analysis of the four main Magnolia officinalis cultivars in Sichuan province in China identified 125,100 unigenes and 6,012 proteins. Proteomic data and parallel reaction monitoring (PRM) revealed that porphobilinogen deaminase, uroporphyrinogen decarboxylase, oxygen-dependent coproporphyrinogen-III oxidase, protoporphyrinogen oxidase 1, magnesium protoporphyrin IX methyltransferase, magnesium-protoporphyrin IX monomethyl ester oxidative cyclase, and protochlorophyllide reductase-like protein, all of which are involved in chlorophyll synthesis, have higher expression levels in DA than in the other three cultivars. This finding is consistent with the observation that DA has the highest concentration of chlorophyll (37.56 mg/g Fw) of the four cultivars. This research is beneficial to the understanding of the differences in the growth of the four cultivars on the molecular level.

Zebrafish models for human ALA-dehydratase-deficient porphyria (ADP) and hereditary coproporphyria (HCP) generated with TALEN and CRISPR-Cas9

ABSTRACTDefects in the enzymes involved in heme biosynthesis result in a group of human metabolic genetic disorders known as porphyrias. Using a zebrafish model for human hepatoerythropoietic porphyria (HEP), caused by defective uroporphyrinogen decarboxylase (Urod), the fifth enzyme in the heme biosynthesis pathway, we recently have found a novel aspect of porphyria pathogenesis. However, no hereditable zebrafish models with genetic mutations ofaladandcpox, encoding the second enzyme delta-aminolevulinate dehydratase (Alad) and the sixth enzyme coproporphyrinogen oxidase (Cpox), have been established to date. Here we employed site-specific genome-editing tools transcription activator-like effector nuclease (TALEN) and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) to generate zebrafish mutants foraladandcpox. These zebrafish mutants display phenotypes of heme deficiency, hypochromia, abnormal erythrocytic maturation and accumulation of heme precursor intermediates, reminiscent of human ALA-dehydratase-deficient porphyria (ADP) and hereditary coproporphyrian (HCP), respectively. Further, we observed altered expression of genes involved in heme biosynthesis and degradation and particularly down-regulation of exocrine pancreatic zymogens in ADP (alad-/-) and HCP (cpox-/-) fishes. These two zebrafish porphyria models can survive at least 7 days and thus provide invaluable resources for elucidating novel pathological aspects of porphyrias, evaluating mutated forms of humanALADandCPOX, discovering new therapeutic targets and developing effective drugs for these complex genetic diseases. Our studies also highlight generation of zebrafish models for human diseases with two versatile genome-editing tools.