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Biology subjects

Heitplatz, B.

Publications and source records attributed to Heitplatz, B..

2 recordsLinked to original sources

Treatment with 2-phospho-L-ascorbic acid mitigates biochemical phenotypes of heme oxygenase 1 deficiency

Heme oxygenase 1 (HO-1) deficiency is a fatal genetic disorder characterized by impaired heme catabolism, leading to excessive oxidative damage and cell death. Despite evidence from non-human models suggesting mitochondrial dysfunction, the precise pathomechanisms in humans remain unclear, resulting in a lack of effective treatments. Using patient-derived lymphoblastoid cells and HO-1 knockout HEK293T cell models, we demonstrate that HO-1 deficiency is associated with altered mitochondrial morphology and impaired mitochondrial function. Furthermore, it is linked to significant ascorbic acid depletion, accompanied by compensatory upregulation of SVCT2, a key ascorbic acid transporter. Treatment with 2-phospho-L-ascorbic acid, a stable vitamin C analog, restores intracellular ascorbic acid levels and protects cells from hemin-induced cytotoxicity, highlighting its potential as a novel therapeutic strategy for HO-1 deficiency. Our study underscores the critical role of oxidative stress and mitochondrial dysfunction in HO-1 deficiency, paving the way for targeted interventions in this devastating disorder.

molecular biology↗

Microvascular immunity is organ-specific and concealed in peripheral blood

Blood tests are a common method for diagnosing and monitoring various health conditions. Nevertheless, the extent to which phlebotomy can offer insights into immune and organ dysfunction remains uncertain. Here, we conducted a comprehensive analysis of blood-borne leukocytes in the microvasculature of different mouse organs and compared it to peripheral blood and parenchymal samples. We observed that microvascular immune cells outnumber tissue-resident counterparts in the kidney, liver and lung. Classical monocytes and lymphocytes are diminished while nonclassical and SSC-high monocytes are enriched compared to blood. Utilizing single-cell sequencing, we identified specific cell populations up to 100-fold expanded in the kidney vasculature including macrophages, plasmacytoid dendritic cells, B cells, and innate lymphoid cells type 2. Microvascular enrichment could trigger a local phenotype switch as shown in glomerulus-restricted B cells. Peritonitis and acute kidney injury (AKI) elicited a multifaceted and systemic response of microvascular leukocytes. It involved remote organ effects, such as a 16-fold increase of leukocytes in the splenic circulation or 64-fold increase of SSC-high monocytes in the liver circulation that was not detectable in the peripheral blood or the tissue. Following full recovery from AKI, persistent and complex changes were observed predominantly in the renal vasculature, while most leukocytes in the peripheral blood had already returned to baseline levels. Collectively, our findings suggest a paradigm of organ- and disease-specific microvascular immunity that largely eludes conventional blood and tissue analysis.

immunology↗