Loss of Ift74 Leads to Slow Photoreceptor Degeneration and Ciliogenesis Defects in Zebrafish

Cilia are microtubule-based structures projecting from the cell surface that perform diverse biological functions. Ciliary defects can cause a wide range of genetic disorders known collectively as ciliopathies. Intraflagellar transport (IFT) proteins are essential for the assembly and maintenance of cilia by transporting proteins along the axoneme. Here, we report a lack of Ift74, a core IFT-B protein, leading to ciliogenesis defects in multiple organs during early zebrafish development. Unlike rapid photoreceptor cell death in other ift-b mutants, the photoreceptors of ift74 mutants exhibited a slow degeneration process. Further experiments demonstrated that the connecting cilia of ift74 mutants were initially formed but failed to maintain, which resulted in slow opsin transport efficiency and eventually led to photoreceptor cell death. We also showed that the large amount of maternal ift74 transcripts deposited in zebrafish eggs account for the main reason of slow photoreceptor degeneration in the mutants. Together, our data suggested Ift74 is critical for ciliogenesis and that Ift proteins play variable roles in different types of cilia during early zebrafish development. To our knowledge, this is the first study to show ift-b mutant that displays slow photoreceptor degeneration in zebrafish.

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Redefining the role of Ca2+-permeable channels in photoreceptor degeneration using diltiazem

Cell Death and Disease ◽

10.1038/s41419-021-04482-1 ◽

2022 ◽

Vol 13 (1) ◽

Author(s):

Soumyaparna Das ◽

Valerie Popp ◽

Michael Power ◽

Kathrin Groeneveld ◽

Jie Yan ◽

...

Keyword(s):

Cell Death ◽

Retinal Degeneration ◽

Photoreceptor Cell ◽

Strong Increase ◽

Channel Blockers ◽

Photoreceptor Degeneration ◽

Therapy Development ◽

Hypertensive Drug ◽

Future Therapy

AbstractHereditary degeneration of photoreceptors has been linked to over-activation of Ca2+-permeable channels, excessive Ca2+-influx, and downstream activation of Ca2+-dependent calpain-type proteases. Unfortunately, after more than 20 years of pertinent research, unequivocal evidence proving significant and reproducible photoreceptor protection with Ca2+-channel blockers is still lacking. Here, we show that both D- and L-cis enantiomers of the anti-hypertensive drug diltiazem were very effective at blocking photoreceptor Ca2+-influx, most probably by blocking the pore of Ca2+-permeable channels. Yet, unexpectedly, this block neither reduced the activity of calpain-type proteases, nor did it result in photoreceptor protection. Remarkably, application of the L-cis enantiomer of diltiazem even led to a strong increase in photoreceptor cell death. These findings shed doubt on the previously proposed links between Ca2+ and retinal degeneration and are highly relevant for future therapy development as they may serve to refocus research efforts towards alternative, Ca2+-independent degenerative mechanisms.

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Minocycline decreases CCR2-positive monocytes in the retina and ameliorates photoreceptor degeneration in a mouse model of retinitis pigmentosa

PLoS ONE ◽

10.1371/journal.pone.0239108 ◽

2021 ◽

Vol 16 (4) ◽

pp. e0239108

Author(s):

Ryo Terauchi ◽

Hideo Kohno ◽

Sumiko Watanabe ◽

Saburo Saito ◽

Akira Watanabe ◽

...

Keyword(s):

Cell Death ◽

Retinal Degeneration ◽

Photoreceptor Cell ◽

Fluorescent Protein ◽

Outer Nuclear Layer ◽

Inhibitory Effect ◽

Subretinal Space ◽

Photoreceptor Degeneration ◽

Retinal Inflammation ◽

Green Fluorescent

Retinal inflammation accelerates photoreceptor cell death caused by retinal degeneration. Minocycline, a semisynthetic broad-spectrum tetracycline antibiotic, has been previously reported to rescue photoreceptor cell death in retinal degeneration. We examined the effect of minocycline on retinal photoreceptor degeneration using c-mer proto-oncogene tyrosine kinase (Mertk)−/−Cx3cr1GFP/+Ccr2RFP/+ mice, which enabled the observation of CX3CR1-green fluorescent protein (GFP)- and CCR2-red fluorescent protein (RFP)-positive macrophages by fluorescence. Retinas of Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice showed photoreceptor degeneration and accumulation of GFP- and RFP-positive macrophages in the outer retina and subretinal space at 6 weeks of age. Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice were intraperitoneally administered minocycline. The number of CCR2-RFP positive cells significantly decreased after minocycline treatment. Furthermore, minocycline administration resulted in partial reversal of the thinning of the outer nuclear layer and decreased the number of apoptotic cells, as assessed by the TUNEL assay, in Mertk−/−Cx3cr1GFP/+Ccr2RFP/+ mice. In conclusion, we found that minocycline ameliorated photoreceptor cell death in an inherited photoreceptor degeneration model due to Mertk gene deficiency and has an inhibitory effect on CCR2 positive macrophages, which is likely to be a neuroprotective mechanism of minocycline.

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Fifteen years of research on oral–facial–digital syndromes: from 1 to 16 causal genes

Journal of Medical Genetics ◽

10.1136/jmedgenet-2016-104436 ◽

2017 ◽

Vol 54 (6) ◽

pp. 371-380 ◽

Cited By ~ 37

Author(s):

Ange-Line Bruel ◽

Brunella Franco ◽

Yannis Duffourd ◽

Julien Thevenon ◽

Laurence Jego ◽

...

Keyword(s):

Transition Zone ◽

Genetic Disorders ◽

Intraflagellar Transport ◽

Heterozygous Mutation ◽

Type I ◽

Gene Encoding ◽

Distinct Subgroup ◽

Functional Studies ◽

New Genes ◽

Wide Range

Oral–facial–digital syndromes (OFDS) gather rare genetic disorders characterised by facial, oral and digital abnormalities associated with a wide range of additional features (polycystic kidney disease, cerebral malformations and several others) to delineate a growing list of OFDS subtypes. The most frequent, OFD type I, is caused by a heterozygous mutation in theOFD1gene encoding a centrosomal protein. The wide clinical heterogeneity of OFDS suggests the involvement of other ciliary genes. For 15 years, we have aimed to identify the molecular bases of OFDS. This effort has been greatly helped by the recent development of whole-exome sequencing (WES). Here, we present all our published and unpublished results for WES in 24 cases with OFDS. We identified causal variants in five new genes (C2CD3,TMEM107,INTU,KIAA0753andIFT57) and related the clinical spectrum of four genes in other ciliopathies (C5orf42,TMEM138,TMEM231andWDPCP) to OFDS. Mutations were also detected in two genes previously implicated in OFDS. Functional studies revealed the involvement of centriole elongation, transition zone and intraflagellar transport defects in OFDS, thus characterising three ciliary protein modules: the complex KIAA0753-FOPNL-OFD1, a regulator of centriole elongation; the Meckel-Gruber syndrome module, a major component of the transition zone; and the CPLANE complex necessary for IFT-A assembly. OFDS now appear to be a distinct subgroup of ciliopathies with wide heterogeneity, which makes the initial classification obsolete. A clinical classification restricted to the three frequent/well-delineated subtypes could be proposed, and for patients who do not fit one of these three main subtypes, a further classification could be based on the genotype.

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Redefining the role of Ca2+-permeable channels in hereditary photoreceptor degeneration using the D- and L-cis enantiomers of diltiazem

10.1101/2020.12.04.411827 ◽

2020 ◽

Author(s):

Soumyaparna Das ◽

Valerie Popp ◽

Michael Power ◽

Kathrin Groeneveld ◽

Christian Melle ◽

...

Keyword(s):

Cell Death ◽

Photoreceptor Cell ◽

Strong Increase ◽

Channel Blockers ◽

Photoreceptor Degeneration ◽

Therapy Development ◽

Hypertensive Drug ◽

Future Therapy ◽

Reduced Activity

ABSTRACTHereditary degeneration of photoreceptors has been linked to over-activation of Ca2+-permeable channels, excessive Ca2+-influx, and downstream activation of Ca2+-dependent calpain-type proteases. Unfortunately, after more than 20 years of pertinent research, unequivocal evidence proving significant and reproducible photoreceptor protection with Ca2+-channel blockers is still lacking. Here, we show that both D- and L-cis enantiomers of the anti-hypertensive drug diltiazem were highly effective at blocking photoreceptor Ca2+-influx, most probably by blocking the pores of Ca2+-permeable channels. Yet, unexpectedly, this block neither reduced activity of calpain-type proteases, nor did it result in photoreceptor protection. Remarkably, application of the L-cis enantiomer of diltiazem even led to a strong increase in photoreceptor cell death. These findings shed doubt on the previously proposed links between Ca2+ and retinal degeneration and are highly relevant for future therapy development as they may serve to refocus research efforts towards alternative, Ca2+-independent degenerative mechanisms.

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Apoptosis Signaling In Retinas Of Mice With Inherited Photoreceptor Degeneration.

Microscopy and Microanalysis ◽

10.1017/s1431927600019851 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 1306-1307

Author(s):

K. A. Rich

Keyword(s):

Cell Death ◽

Signaling Pathways ◽

Cell Apoptosis ◽

Photoreceptor Cell ◽

Β Subunit ◽

Photoreceptor Degeneration ◽

Photoreceptor Layer ◽

Outer Segments ◽

Eye Opening ◽

Immunocytochemical Approach

The signaling pathways which lead to the wave of photoreceptor cell death in the rd mouse during the second week after birth have yet to be defined. The photoreceptors of these mice develop normally until they begin to elaborate phototransducing outer segments at around postnatal day (P)8. At this point, their differentiation slows as intracellular levels of cGMP rise due to the inherited mutation in the phosphodiesterase-β subunit.We have used an immunocytochemical approach to investigate potential signaling pathways leading to photoreceptor cell apoptosis in this mutant. The earliest change detected in the photoreceptor layer was an induction of CREB immunoreactivity in photoreceptor nuclei, commencing at P8. Although CREB is generally thought to be constitutively expressed and its function controlled primarily by its phosphorylation, we find that immature photoreceptors of normal mice are immunonegative for CREB until the time of eye opening and the initiation of phototransduction at around P14.

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High dose expression of heme oxigenase-1 induces retinal degeneration through ER stress-related DDIT3

Molecular Neurodegeneration ◽

10.1186/s13024-021-00437-4 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Huirong Li ◽

Bo Liu ◽

Lili Lian ◽

Jiajia Zhou ◽

Shengjin Xiang ◽

...

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Retinal Degeneration ◽

Knockout Mice ◽

Photoreceptor Cell ◽

Heme Oxygenase 1 ◽

High Dose ◽

Photoreceptor Degeneration ◽

Expression Levels ◽

High Level

Abstract Background Oxidative stress is a common cause of neurodegeneration and plays a central role in retinal degenerative diseases. Heme oxygenase-1 (HMOX1) is a redox-regulated enzyme that is induced in neurodegenerative diseases and acts against oxidative stress but can also promote cell death, a phenomenon that is still unexplained in molecular terms. Here, we test whether HMOX1 has opposing effects during retinal degeneration and investigate the molecular mechanisms behind its pro-apoptotic role. Methods Basal and induced levels of HMOX1 in retinas are examined during light-induced retinal degeneration in mice. Light damage-independent HMOX1 induction at two different expression levels is achieved by intraocular injection of different doses of an adeno-associated virus vector expressing HMOX1. Activation of Müller glial cells, retinal morphology and photoreceptor cell death are examined using hematoxylin-eosin staining, TUNEL assays, immunostaining and retinal function are evaluated with electroretinograms. Downstream gene expression of HMOX1 is analyzed by RNA-seq, qPCR examination and western blotting. The role of one of these genes, the pro-apoptotic DNA damage inducible transcript 3 (Ddit3), is analyzed in a line of knockout mice. Results Light-induced retinal degeneration leads to photoreceptor degeneration and concomitant HMOX1 induction. HMOX1 expression at low levels before light exposure prevents photoreceptor degeneration but expression at high levels directly induces photoreceptor degeneration even without light stress. Photoreceptor degeneration following high level expression of HMOX1 is associated with a mislocalization of rhodopsin in photoreceptors and an increase in the expression of DDIT3. Genetic deletion of Ddit3 in knockout mice prevents photoreceptor cell degeneration normally resulting from high level HMOX1 expression. Conclusion The results reveal that the expression levels determine whether HMOX1 is protective or deleterious in the retina. Furthermore, in contrast to the protective low dose of HMOX1, the deleterious high dose is associated with induction of DDIT3 and endoplasmic reticulum stress as manifested, for instance, in rhodopsin mislocalization. Hence, future applications of HMOX1 or its regulated targets in gene therapy approaches should carefully consider expression levels in order to avoid potentially devastating effects.

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The role of cGMP-signalling and calcium-signalling in photoreceptor cell death: perspectives for therapy development

Pflügers Archiv - European Journal of Physiology ◽

10.1007/s00424-021-02556-9 ◽

2021 ◽

Author(s):

Soumyaparna Das ◽

Yiyi Chen ◽

Jie Yan ◽

Gustav Christensen ◽

Soumaya Belhadj ◽

...

Keyword(s):

Cell Death ◽

Photoreceptor Cell ◽

Second Messengers ◽

Calcium Signalling ◽

Clinical Applications ◽

Photoreceptor Degeneration ◽

Therapeutic Approaches ◽

Cgmp Signalling ◽

Key Aspects

AbstractThe second messengers, cGMP and Ca2+, have both been implicated in retinal degeneration; however, it is still unclear which of the two is most relevant for photoreceptor cell death. This problem is exacerbated by the close connections and crosstalk between cGMP-signalling and calcium (Ca2+)-signalling in photoreceptors. In this review, we summarize key aspects of cGMP-signalling and Ca2+-signalling relevant for hereditary photoreceptor degeneration. The topics covered include cGMP-signalling targets, the role of Ca2+ permeable channels, relation to energy metabolism, calpain-type proteases, and how the related metabolic processes may trigger and execute photoreceptor cell death. A focus is then put on cGMP-dependent mechanisms and how exceedingly high photoreceptor cGMP levels set in motion cascades of Ca2+-dependent and independent processes that eventually bring about photoreceptor cell death. Finally, an outlook is given into mutation-independent therapeutic approaches that exploit specific features of cGMP-signalling. Such approaches might be combined with suitable drug delivery systems for translation into clinical applications.

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Nanoparticles Functionalized with Venom-Derived Peptides and Toxins for Pharmaceutical Applications

Current Pharmaceutical Biotechnology ◽

10.2174/1389201020666190621104624 ◽

2020 ◽

Vol 21 (2) ◽

pp. 97-109 ◽

Cited By ~ 1

Author(s):

Ana P. dos Santos ◽

Tamara G. de Araújo ◽

Gandhi Rádis-Baptista

Keyword(s):

Oral Absorption ◽

Current Data ◽

Pharmacological Activities ◽

Venom Peptides ◽

Essential Components ◽

Wide Range ◽

Different Types ◽

Direct Use ◽

Animal Venoms ◽

Pharmaceutical Biotechnology

Venom-derived peptides display diverse biological and pharmacological activities, making them useful in drug discovery platforms and for a wide range of applications in medicine and pharmaceutical biotechnology. Due to their target specificities, venom peptides have the potential to be developed into biopharmaceuticals to treat various health conditions such as diabetes mellitus, hypertension, and chronic pain. Despite the high potential for drug development, several limitations preclude the direct use of peptides as therapeutics and hamper the process of converting venom peptides into pharmaceuticals. These limitations include, for instance, chemical instability, poor oral absorption, short halflife, and off-target cytotoxicity. One strategy to overcome these disadvantages relies on the formulation of bioactive peptides with nanocarriers. A range of biocompatible materials are now available that can serve as nanocarriers and can improve the bioavailability of therapeutic and venom-derived peptides for clinical and diagnostic application. Examples of isolated venom peptides and crude animal venoms that have been encapsulated and formulated with different types of nanomaterials with promising results are increasingly reported. Based on the current data, a wealth of information can be collected regarding the utilization of nanocarriers to encapsulate venom peptides and render them bioavailable for pharmaceutical use. Overall, nanomaterials arise as essential components in the preparation of biopharmaceuticals that are based on biological and pharmacological active venom-derived peptides.

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Reverse Screening Bioinformatics Approach to Identify Potential Anti Breast Cancer Targets Using Thymoquinone from Neutraceuticals Black Cumin Oil

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520619666190124155359 ◽

2019 ◽

Vol 19 (5) ◽

pp. 599-609 ◽

Cited By ~ 1

Author(s):

Sumathi Sundaravadivelu ◽

Sonia K. Raj ◽

Banupriya S. Kumar ◽

Poornima Arumugamand ◽

Padma P. Ragunathan

Keyword(s):

Breast Cancer ◽

Gene Expression ◽

Cell Cycle ◽

Cell Death ◽

In Silico ◽

Chemotherapeutic Agents ◽

Normal Cells ◽

Black Cumin ◽

In Silico Docking ◽

Wide Range

Background: Functional foods, neutraceuticals and natural antioxidants have established their potential roles in the protection of human health and diseases. Thymoquinone (TQ), the main bioactive component of Nigella sativa seeds (black cumin seeds), a plant derived neutraceutical was used by ancient Egyptians because of their ability to cure a variety of health conditions and used as a dietary food supplement. Owing to its multi targeting nature, TQ interferes with a wide range of tumorigenic processes and counteracts carcinogenesis, malignant growth, invasion, migration, and angiogenesis. Additionally, TQ can specifically sensitize tumor cells towards conventional cancer treatments (e.g., radiotherapy, chemotherapy, and immunotherapy) and simultaneously minimize therapy-associated toxic effects in normal cells besides being cost effective and safe. TQ was found to play a protective role when given along with chemotherapeutic agents to normal cells. Methods: In the present study, reverse in silico docking approach was used to search for potential molecular targets for cancer therapy. Various metastatic and apoptotic targets were docked with the target ligand. TQ was also tested for its anticancer activities for its ability to cause cell death, arrest cell cycle and ability to inhibit PARP gene expression. Results: In silico docking studies showed that TQ effectively docked metastatic targets MMPs and other apoptotic and cell proliferation targets EGFR. They were able to bring about cell death mediated by apoptosis, cell cycle arrest in the late apoptotic stage and induce DNA damage too. TQ effectively down regulated PARP gene expression which can lead to enhanced cancer cell death. Conclusion: Thymoquinone a neutraceutical can be employed as a new therapeutic agent to target triple negative breast cancer which is otherwise difficult to treat as there are no receptors on them. Can be employed along with standard chemotherapeutic drugs to treat breast cancer as a combinatorial therapy.

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Wetting of glass surface using natural surfactants

Micro and Nanosystems ◽

10.2174/1876402912666200219111447 ◽

2020 ◽

Vol 12 ◽

Author(s):

Nihar Ranjan Biswal

Keyword(s):

Contact Angle ◽

Glass Surface ◽

Pure Water ◽

Amyl Alcohol ◽

Synthetic Surfactant ◽

Wide Range ◽

Different Types ◽

Natural Surfactants ◽

Triton X ◽

Solid Liquid

Background: Surfactant adsorption at the interfaces (solid–liquid, liquid–air, or liquid–liquid) is receiving considerable attention from a long time due to its wide range of practical applications. Objective: Specifically wettability of solid surface by liquids is mainly measured by contact angle and has many practical importances where solid–liquid systems are used. Adsorption of surfactants plays an important role in the wetting process. The wetting behaviours of three plant-based natural surfactants (Reetha, Shikakai, and Acacia) on the glass surface are compared with one widely used nonionic synthetic surfactant (Triton X-100) and reported in this study. Methods: The dynamic contact angle study of three different types of plant surfactants (Reetha, Shikakai and Acacia) and one synthetic surfactant (Triton X 100) on the glass surface has been carried out. The effect of two different types of alcohols such as Methanol and amyl alcohol on wettability of shikakai, as it shows little higher value of contact angle on glass surface has been measured. Results: The contact angle measurements show that there is an increase in contact angle from 47° (pure water) to 67.72°, 65.57°, 68.84°, and 68.79° for Reetha, Acacia, Shikakai, and Triton X-100 respectively with the increase in surfactant concentration and remain constant at CMC. The change in contact angle of Shikakai-Amyl alcohol mixtures are slightly different than that of methanol-Shikakai mixture, mostly there is a gradual increase in contact angle with the increasing in alcohol concentration. Conclusion: There is no linear relationship between cos θ and inverse of surface tension. There was a linear increase in surface free energy results with increase in concentration as more surfactant molecules were adsorbing at the interface enhancing an increase in contact angle.

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