Proteomic analysis unveils Gb3-independent alterations and mitochondrial dysfunction in a gla-/- zebrafish model of Fabry disease.

BACKGROUND: Fabry disease (FD) is a rare lysosomal storage disorder caused by mutations in the GLA gene, resulting in reduced or lack of α-galactosidase A activity. This results in the accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids in lysosomes causing cellular impairment and organ failures. While current therapies focus on reversing Gb3 accumulation, they do not address the altered cellular signaling in FD. Therefore, this study aims to explore Gb3-independent mechanisms of kidney damage in Fabry disease and identify potential biomarkers. METHODS: To investigate these mechanisms, we utilized a zebrafish (ZF) gla-/- mutant (MU) model. ZF naturally lack A4GALT gene and, therefore, cannot synthesize Gb3. We obtained kidney samples from both wild-type (WT) (n = 8) and MU (n = 8) ZF and conducted proteome profiling using untargeted mass spectrometry. Additionally, we examined mitochondria morphology and cristae morphology using electron microscopy. To assess oxidative stress, we measured total antioxidant activity. Finally, immunohistochemistry was conducted on kidney samples to validate specific proteins. RESULTS: Our proteomics analysis of renal tissues from zebrafish revealed downregulation of lysosome and mitochondrial-related proteins in gla-/- MU renal tissues, while energy-related pathways including carbon, glycolysis, and galactose metabolisms were disturbed. Moreover, we observed abnormal mitochondrial shape, disrupted cristae morphology, altered mitochondrial volume and lower antioxidant activity in gla-/- MU ZF. CONCLUSIONS: These results suggest that the alterations observed at the proteome and mitochondrial level closely resemble well-known GLA mutation-related alterations in humans. Importantly, they also unveil novel Gb3-independent pathogenic mechanisms in Fabry disease. Understanding these mechanisms could potentially lead to the development of innovative drug screening approaches. Furthermore, the findings pave the way for identifying new clinical targets, offering new avenues for therapeutic interventions in Fabry disease. The zebrafish gla-/- mutant model proves valuable in elucidating these mechanisms and may contribute significantly to advancing our knowledge of this disorder.

Reduced α-galactosidase A activity in zebrafish (Danio rerio) mirrors distinct features of Fabry nephropathy phenotype.

Fabry disease (FD) is a rare genetic lysosomal storage disorder, resulting from partial or complete lack of alpha-galactosidase A (α-GAL) enzyme, leading to systemic accumulation of substrate glycosphingolipids with a broad range of tissue damage. Current in vivo models are laborious, expensive, and fail to adequately mirror the complex FD physiopathology. To address these issues, we developed an innovative FD model in zebrafish. Zebrafish GLA gene encoding α-GAL enzyme presents a high (>70%) homology with its human counterpart, and the corresponding protein has a similar tissue distribution, as evaluated by immunohistochemistry. Moreover, a similar enzymatic activity in different life stages could be demonstrated. By using CRISPR/Cas9 technology, we generated a mutant zebrafish with decreased GLA gene expression, and decreased expression of the specific gene product in the kidney. Mutant animals showed higher plasma creatinine levels and proteinuria. Transmission electron microscopy (TEM) studies documented an increased podocyte foot process width (FPW) in mutant, as compared to wild type zebrafish. This zebrafish model reliably mirrors distinct features of human FD and could be advantageously used for the identification of novel biomarkers and for an effective screening of innovative therapeutic approaches.

Gene Expression Analysis in gla-Mutant Zebrafish Reveals Enhanced Ca2+ Signaling Similar to Fabry Disease.

Fabry disease (FD) is an X-linked inborn metabolic disorder due to partial or complete lysosomal α-galactosidase A deficiency. FD is characterized by progressive renal insufficiency and cardio- and cerebrovascular involvement. Restricted access on Gb3-independent tissue injury experimental models has limited the understanding of FD pathophysiology and delayed the development of new therapies. Accumulating glycosphingolipids, mainly Gb3 and lysoGb3, are Fabry specific markers used in clinical follow up. However, recent studies suggest there is a need for additional markers to monitor FD clinical course or response to treatment. We used a gla-knockout zebrafish (ZF) to investigate alternative biomarkers in Gb3-free-conditions. RNA sequencing was used to identify transcriptomic signatures in kidney tissues discriminating gla-mutant (M) from wild type (WT) ZF. Gene Ontology (GO) and KEGG pathways analysis showed upregulation of immune system activation and downregulation of oxidative phosphorylation pathways in kidneys from M ZF. In addition, upregulation of the Ca2+ signaling pathway was also detectable in M ZF kidneys. Importantly, disruption of mitochondrial and lysosome-related pathways observed in M ZF was validated by immunohistochemistry. Thus, this ZF model expands the pathophysiological understanding of FD, the Gb3-independent effects of gla mutations could be used to explore new therapeutic targets for FD.

Axl-inhibitor bemcentinib alleviates mitochondrial dysfunction in the unilateral ureter obstruction murine model.

Renal fibrosis is a progressive histological manifestation leading to chronic kidney disease (CKD) and associated with mitochondrial dysfunction. In previous work, we showed that Bemcentinib, an Axl receptor tyrosine kinase inhibitor, reduced fibrosis development. In this study, to investigate its effects on mitochondrial dysfunction in renal fibrosis, we analysed genome-wide transcriptomics data from a unilateral ureter obstruction (UUO) murine model in the presence or absence of bemcentinib (n = 6 per group) and SHAM-operated (n = 4) mice. Kidney ligation resulted in dysregulation of mitochondria-related pathways, with a significant reduction in the expression of oxidative phosphorylation (OXPHOS), fatty acid oxidation (FAO), citric acid cycle (TCA), response to reactive oxygen species and amino acid metabolism-related genes. Bemcentinib treatment increased the expression of these genes. In contrast, AKT/PI3K signalling pathway genes were up-regulated upon UUO, but bemcentinib largely inhibited their expression. At the functional level, ligation reduced mitochondrial biomass, which was increased upon bemcentinib treatment. Serum metabolomics analysis also showed a normalizing amino acid profile in UUO, compared with SHAM-operated mice following bemcentinib treatment. Our data suggest that mitochondria and mitochondria-related pathways are dramatically affected by UUO surgery and treatment with Axl-inhibitor bemcentinib partially reverses these effects.

Detection of AZF microdeletions and reproductive hormonal profile analysis of infertile sudanese men pursuing assisted reproductive approaches.

BACKGROUND: Male factor is the major contributor in roughly half of infertility cases. Genetic factors account for 10-15% of male infertility. Microdeletions of azoospermia factors (AZF) on the Yq region are the second most frequent spermatogenesis disorder among infertile men after Klinefelter syndrome. We detected in our previous study a frequency of 37.5% AZF microdeletions which investigated mainly the AZFb and AZFc. We attempted in this study for the first time to evaluate the frequencies of all AZF sub-regions microdeletions and to analyze reproductive hormonal profiles in idiopathic cases of azoospermic and oligozoospermic men from Sudan. METHODS: A group of 51 medically fit infertile men were subjected to semen analysis. Four couples have participated in this study as a control group. Semen analysis was performed according to WHO criteria by professionals at Elsir Abu-Elhassan Fertility Centre where samples have been collected. We detected 12 STSs markers of Y chromosome AZF microdeletions using a multiplex polymerase chain reaction. Analysis of reproductive hormone levels including Follicle Stimulating, Luteinizing, and Prolactin hormones was performed using ELISA. Comparisons between outcome groups were performed using Student's t-test Chi-square test or Fisher's exact test. RESULTS: AZF microdeletion was identified in 16 out of 25 Azoospermic and 14 out of 26 of the Oligozoospermic. Microdeletion in the AZFa region was the most frequent among the 30 patients (N = 11) followed by AZFc, AZFd (N = 4 for each) and AZFb (N = 3). Among the Oligozoospermic participants, the most frequent deletions detected were in the AZFa region (N = 10 out of 14) and was significantly associated with Oligozoospermic phenotype, Fisher's Exact Test (2-sided) p = 0.009. Among the Azoospermic patients, the deletion of the AZFc region was the most frequent (N = 9 out of 16) and was significantly associated with Azoospermia phenotype Fisher's Exact Test p = 0.026. There was a significant difference in Y chromosome microdeletion frequency between the two groups. The hormonal analysis showed that the mean levels of PRL, LH, and FSH in Azoospermic patients were slightly higher than those in oligozoospermic. A weak negative correlation between prolactin higher level and Azoospermic patients was detected. (AZFa r = 0.665 and 0.602, p = 0.000 and 0.0004, AZFb r = 0.636 and 0.409, p = 0.000 and 0.025, and AZFd r = 0.398 and 0.442, p = 0.029 and 0.015). The correlation was positive for AZFa and negative for AZFb and AZFd. CONCLUSIONS: We concluded in this study that the incidences of microdeletions of the Y chromosome confined to AZF a, b, c and d regions is 58.8% in infertile subjects with 31.4% were Azoospermic and 27.5% were Oligozoospermic. This might provide a piece of evidence that these specified regions of the Y chromosome are essential for controlling spermatogenesis. These findings will be useful for genetic counseling within infertility clinics in Sudan and to adopt appropriate methods for assisted reproduction.

Elevated Ambulatory Blood Pressure Measurements are Associated with a Progressive Form of Fabry Disease.

 INTRODUCTION: Published data on hypertension incidence and management in Anderson-Fabry disease are scant and the contribution of elevated blood pressure to organ damage is not well recognized. AIM: Therefore, we have assessed blood pressure values and their possible correlations with clinical findings in a well described cohort of Fabry patients. METHODS: Between January 2015 and May 2019, all adult Fabry patients (n = 24 females, n = 8 males) referred to our institute were prospectively enrolled. During the first examination patient's genotype and clinical characteristics were recorded. Blood pressure data were obtained by standard observed office measurements followed, within 6 months, by ambulatory blood pressure monitoring and home self-recordings. Organ involvement, including kidneys, heart and brain, was monitored over time. Consequently, patients were defined as clinically stable or progressive through the Fabry Stabilization Index. RESULTS: The standard office measurements have diagnosed hypertension in three (9.37%) patients, but the ambulatory monitoring showed elevated blood pressure in six (18.75%) patients, revealing three cases of masked hypertension. All the hypertensive patients were females and, compared with normotensive subjects, they presented a lower glomerular filtration rate (p < 0.05) and a more advanced cardiac hypertrophy (p < 0.05). Four (66.7%) of them were diagnosed with a progressive form of the disease through the Fabry Stabilization Index while the majority of the normotensive group (84.6%, n = 19) was stable over time. No correlation was found between the prevalence of hypertension and the type of mutations causing Fabry disease. CONCLUSION: Hypertension can be found in a restricted portion of clinically stable Fabry patients. In contrast, patients presenting with a progressive organ involvement, particularly renal impairment, have a major risk of developing uncontrolled blood pressure, and should be followed carefully. Moreover, the ambulatory blood pressure monitoring proved to be useful to reveal masked hypertension, which can contribute to the progressive worsening of the organ damage. Therefore, a proper diagnosis and therapy of hypertension may improve the outcome of Fabry patients.