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Function (Oxford, England) 2024Modern neuroscience is progressively elucidating that the classic view positing distinct brain regions responsible for survival, emotion, and cognitive functions is... (Review)
Review
Modern neuroscience is progressively elucidating that the classic view positing distinct brain regions responsible for survival, emotion, and cognitive functions is outdated. The hypothalamus demonstrates the interdependence of these roles, as it is traditionally known for fundamental survival functions like energy and electrolyte balance, but is now recognized to also play a crucial role in emotional and cognitive processes. This review focuses on lateral hypothalamic melanin-concentrating hormone (MCH) neurons, producing the neuropeptide MCH-a relatively understudied neuronal population with integrative functions related to homeostatic regulation and motivated behaviors, with widespread inputs and outputs throughout the entire central nervous system. Here, we review early findings and recent literature outlining their role in the regulation of energy balance, sleep, learning, and memory processes.
Topics: Hypothalamic Hormones; Hypothalamus; Neurons; Cognition
PubMed: 38020069
DOI: 10.1093/function/zqad059 -
Frontiers in Medicine 2023Lichen sclerosus et atrophicus (LS) is rare skin condition characterized by the presence of whitish patches primarily affecting the genital and perianal areas, though it...
INTRODUCTION
Lichen sclerosus et atrophicus (LS) is rare skin condition characterized by the presence of whitish patches primarily affecting the genital and perianal areas, though it can occur other parts of the body. LS may result in skin depigmentation without textural changes and should be differentiated from vitiligo. However, the histopathological features of hypopigmentation during vitiligo and LS have rarely been compared and have not been precisely described using quantitative immunohistochemical analysis. This study, therefore, aimed to investigate and compare the pigmentary characteristics of LS and vitiligo lesions using histochemical and immunohistochemical staining.
METHODS
We included 31 and 46 patients diagnosed with LS and vitiligo, respectively, at Ajou University Hospital between March 2009 and March 2020 in this study. Their medical charts and skin biopsy specimens were retrospectively reviewed. Additionally, Fontana-Masson staining for melanin and immunohistochemical staining for Melan-A, NKI/beteb, tyrosinase, and microphthalmia-associated transcription factor was performed.
RESULTS
The melanin content, as well as the number of melanocytes was, in general, significantly higher in the epidermis of patients in the LS group compared with that in the vitiligo group. However, 22.6% of LS tissues showed less melanin pigmentation, 25.8% of LS specimens exhibited a lower number of melanocytes, and 29.0% of LS specimens demonstrated less melanocyte activity when compared with the average of vitiligo specimens.
CONCLUSION
As lower melanin pigmentation and the near absence number of melanocytes were also observed in several LS specimens, both the clinical and histological findings must be comprehensively reviewed to differentiate vitiligo from LS.
PubMed: 37521337
DOI: 10.3389/fmed.2023.1205909 -
BMC Biology Oct 2023Melanin plays important roles in morphological development, survival, host-pathogen interactions and in the virulence of phytopathogenic fungi. In Verticillum dahliae,...
BACKGROUND
Melanin plays important roles in morphological development, survival, host-pathogen interactions and in the virulence of phytopathogenic fungi. In Verticillum dahliae, increases in melanin are recognized as markers of maturation of microsclerotia which ensures the long-term survival and stress tolerance, while decreases in melanin are correlated with increased hyphal growth in the host. The conserved upstream components of the VdCmr1-regulated pathway controlling melanin production in V. dahliae have been extensively identified, but the direct activators of this pathway are still unclear.
RESULTS
We identified two genes encoding conserved C2H2-type zinc finger proteins VdZFP1 and VdZFP2 adjacent to VdPKS9, a gene encoding a negative regulator of both melanin biosynthesis and microsclerotia formation in V. dahliae. Both VdZFP1 and VdZFP2 were induced during microsclerotia development and were involved in melanin deposition. Their localization changed from cytoplasmic to nuclear in response to osmotic pressure. VdZFP1 and VdZFP2 act as modulators of microsclerotia melanization in V. dahliae, as confirmed by melanin biosynthesis inhibition and supplementation with the melanin pathway intermediate scytalone in albino strains. The results indicate that VdZFP1 and VdZFP2 participate in melanin biosynthesis by positively regulating VdCmr1. Based on the results obtained with yeast one- and two-hybrid (Y1H and Y2H) and bimolecular fluorescence complementation (BiFC) systems, we determined the melanin biosynthesis relies on the direct interactions among VdZFP1, VdZFP2 and VdCmr1, and these interactions occur on the cell walls of microsclerotia. Additionally, VdZFP1 and/or VdZFP2 mutants displayed increased sensitivity to stress factors rather than alterations in pathogenicity, reflecting the importance of melanin in stress tolerance of V. dahliae.
CONCLUSIONS
Our results revealed that VdZFP1 and VdZFP2 positively regulate VdCmr1 to promote melanin deposition during microsclerotia development, providing novel insight into the regulation of melanin biosynthesis in V. dahliae.
Topics: Melanins; Fungal Proteins; Verticillium; Ascomycota; Zinc Fingers; Plant Diseases
PubMed: 37904147
DOI: 10.1186/s12915-023-01697-w -
Journal of Translational Medicine Apr 2024Melanocytes are dendritic cells localized in skin, eyes, hair follicles, ears, heart and central nervous system. They are characterized by the presence of melanosomes... (Review)
Review
Melanocytes are dendritic cells localized in skin, eyes, hair follicles, ears, heart and central nervous system. They are characterized by the presence of melanosomes enriched in melanin which are responsible for skin, eye and hair pigmentation. They also have different functions in photoprotection, immunity and sound perception. Melanocyte dysfunction can cause pigmentary disorders, hearing and vision impairments or increased cancer susceptibility. This review focuses on the role of melanocytes in homeostasis and disease, before discussing their potential in regenerative medicine applications, such as for disease modeling, drug testing or therapy development using stem cell technologies, tissue engineering and extracellular vesicles.
Topics: Regenerative Medicine; Melanocytes; Pigmentation; Melanins; Hair Follicle
PubMed: 38589876
DOI: 10.1186/s12967-024-05113-x -
Biochimica Et Biophysica Acta.... Feb 2024Choroideremia (CHM) is a rare X-linked chorioretinal dystrophy affecting the photoreceptors, retinal pigment epithelium (RPE) and choroid, however, the involvement of...
Choroideremia (CHM) is a rare X-linked chorioretinal dystrophy affecting the photoreceptors, retinal pigment epithelium (RPE) and choroid, however, the involvement of the choroid in disease progression is not fully understood. CHM is caused by mutations in the CHM gene, encoding the ubiquitously expressed Rab escort protein 1 (REP1). REP1 plays an important role in intracellular trafficking of vesicles, including melanosomes. In this study, we examined the ultrastructure of the choroid in chm fish and Chm mouse models using transmission electron and confocal microscopy. Significant pigmentary disruptions were observed, with lack of melanosomes in the choroid of chm fish from 4 days post fertilisation (4dpf), and a reduction in choroidal blood vessel diameter and interstitial pillars suggesting a defect in vasculogenesis. Total melanin and expression of melanogenesis genes tyr, tryp1a, mitf, dct and pmel were also reduced from 4dpf. In Chm mice, choroidal melanosomes were significantly smaller at 1 month, with reduced eumelanin at 1 year. The choroid in CHM patients were also examined using spectral domain optical coherence tomography (SD-OCT) and OCT-angiography (OCT-A) and the area of preserved choriocapillaris (CC) was found to be smaller than that of overlying photoreceptors, suggesting that the choroid is degenerating at a faster rate. Histopathology of an enucleated eye from a 74-year-old CHM male patient revealed isolated areas of RPE but no associated underlying CC. Pigmentary disruptions in CHM animal models reveal an important role for REP1 in melanogenesis, and drugs that improve melanin production represent a potential novel therapeutic avenue.
Topics: Aged; Animals; Humans; Male; Mice; Adaptor Proteins, Signal Transducing; Choroid; Choroideremia; Melanins; Melanogenesis; Mice, Knockout
PubMed: 37989423
DOI: 10.1016/j.bbadis.2023.166963 -
JMIR Dermatology Nov 2023Oculocutaneous albinism is a congenital disorder that causes hypopigmentation of the skin, hair, and eyes due to a lack of melanin. People with albinism are at increased...
BACKGROUND
Oculocutaneous albinism is a congenital disorder that causes hypopigmentation of the skin, hair, and eyes due to a lack of melanin. People with albinism are at increased risk of developing skin complications, such as solar keratosis and skin cancers, leading to higher morbidity. As education is crucial in managing albinism, leveraging information technology, such as WhatsApp, can provide an effective intervention for digital health education.
OBJECTIVE
This study aims to assess the impact of WhatsApp as a tool for providing health education among people with albinism.
METHODS
The design of the study was interventional. The intervention consisted of weekly health education sessions conducted in a WhatsApp group for the duration of 4 weeks. The topics discussed were knowledge of albinism, sun protection practices, the use of sunscreen, and myths about albinism. They were all covered in 4 WhatsApp sessions held in 4 separate days. A web-based questionnaire was filled out before and after the intervention by the participants. Mann-Whitney U test was used to compare the pre- and postknowledge scores. Spearman correlation was used to correlate data.
RESULTS
The mean age of the study participants was 28.28 (SD 11.57) years. The number of participants was 140 in the preintervention period and 66 in the postintervention period. A statistically significant increase in overall knowledge (P=.01), knowledge of sunscreen (P=.01), and knowledge of sun protection (P<.01) was observed following the intervention. Before the intervention, a positive correlation was observed between age (r=0.17; P=.03) and education level (r=0.19; P=.02) with participants' overall knowledge. However, after the intervention, there was no significant correlation between knowledge and age or education level. A percentage increase of 5.23% was observed in the overall knowledge scores following the intervention.
CONCLUSIONS
WhatsApp is an effective tool for educating people with albinism and can act as an alternative to the conventional methods of health education. It shows promising outcomes irrespective of the health literacy level of people with albinism. This educational intervention can positively impact behavior change and translate to consistent sun protection practices. The limitations of this study include the possibility of social desirability bias and data security.
PubMed: 37988154
DOI: 10.2196/49950 -
Foods (Basel, Switzerland) Oct 2023Squid ink melanin can be efficiently extracted from the byproduct ink sac generated during squid processing. As a natural food colorant, it possesses inherent...
Squid ink melanin can be efficiently extracted from the byproduct ink sac generated during squid processing. As a natural food colorant, it possesses inherent antioxidant properties and the capability to adsorb heavy metals. This study aims to investigate the solubility of water-soluble squid ink melanin (WSSM) obtained from the ink sac, as well as its stability under various conditions including temperature, pH, salt, sugar, potassium sorbate, metal ions, sodium benzoate, sodium sulfite (reducing agent), and hydrogen peroxide (oxidizing agent). Moreover, it explores the scavenging effects of WSSM on free radicals and cadmium ions. The findings suggest that WSSM's stability is insignificantly affected by high temperature, sucrose, and salt. However, acidity, sodium benzoate, potassium sorbate, sodium sulfite (NaSO), and hydrogen peroxide (HO) significantly influence its stability. Most metal ions do not impact the stability of WSSM, except for Fe, Fe, Al, and Cu, which result in the precipitation of WSSM. Additionally, WSSM exhibits remarkable antioxidant activity with IC values of 0.91, 0.56, and 0.52 mg/mL for scavenging superoxide anion radicals (O·), hydroxyl radicals (·OH), and DPPH radicals, respectively. It also demonstrates the ability to adsorb the heavy metal Cd, with the adsorption rate gradually increasing with a higher temperature and larger amounts of WSSM added. Infrared spectroscopy analysis reveals the weakening of characteristic peaks (-COOH and -OH) during the process of Cd adsorption by WSSM, while SEM confirms surface roughening and structural damage after Cd adsorption. This study provides valuable insights for the utilization of squid melanin products as natural antioxidants and heavy metal adsorbents in the food industry.
PubMed: 37959093
DOI: 10.3390/foods12213963 -
Biochemistry and Biophysics Reports Sep 2023Aberrant melanin overproduction can significantly impact an individual's appearance and cause mental and psychological distress. Current inhibitors of melanin production...
Aberrant melanin overproduction can significantly impact an individual's appearance and cause mental and psychological distress. Current inhibitors of melanin production exert harmful side effects due to inadequate selectivity; thus a need to develop more selective melanin synthesis inhibitors is necessary. Extracellular vesicles are important agents of intercellular signalling in prokaryotes and eukaryotes. Recently, plant-derived nanoparticles, similar to mammalian exosomes, have attracted attention for their use in health research. In this study, to investigate the potential of plant-derived exosome-like nanoparticles (ELNs) as inhibitors of melanin production, we used hot water to extract ELNs from the rhizome of (A-ELNs). The size of A-ENLs ranged from 34 to 401 nm and carried three microRNA: ath-miR166f, ath-miR162a-5p, and ath-miR162b-5p. These A-ENLs were applied to B16-F10 melanoma cells treated with α-melanocyte-stimulating hormone (α-MSH). After A-ELNs were taken up by B16-F10 cells, their melanin levels were significantly reduced. Furthermore, A-ELNs significantly reduced tyrosinase activity in B16-F10 cells and mRNA expression of microphthalmia-associated transcription factor (), tyrosinase, tyrosinase-related protein 1, and DOPA chrome tautomerase. These results suggest that A-ELN suppresses melanogenic enzymes expression by downregulating , thereby inhibiting melanin synthesis. Hence, A-ELN can be developed into a novel topical drug after additional studies and optimization.
PubMed: 37637942
DOI: 10.1016/j.bbrep.2023.101530 -
Frontiers in Microbiology 2023, a highly sought-after edible mushroom worldwide, is evaluated based on its cap color as an essential commercial property indicator. In the present study, the effects...
, a highly sought-after edible mushroom worldwide, is evaluated based on its cap color as an essential commercial property indicator. In the present study, the effects of blue light on cap pigmentation in , as well as the synthesis and structural characteristics of melanin pigments within the cap were examined. The results showed that an increase in the proportion of blue light within the lighting environment promoted melanin synthesis and melanization of the cap. Transmission and scanning electron microscopy revealed the localization of melanin within the mycelium and its ultrastructural characteristics. The UV-visible analysis demonstrated that melanin exhibited a maximum absorption peak at 220 nm and possessed high alkaline solubility as well as acid precipitability. The structural characteristics of melanin were analyzed using FTIR, NMR, HPLC, and elemental analysis, which confirmed the presence of eumelanin, pheomelanin, and allomelanin in both brown and black caps. Furthermore, blue light can stimulate the synthesis of both eumelanin and pheomelanin. The obtained results can serve as the foundation for comprehending the mechanism by which light regulates color formation in mushrooms.
PubMed: 37840742
DOI: 10.3389/fmicb.2023.1276457 -
Brain : a Journal of Neurology Apr 2024Degeneration of the noradrenergic system is now considered a pathological hallmark of Parkinson's disease, but little is known about its consequences in terms of...
Degeneration of the noradrenergic system is now considered a pathological hallmark of Parkinson's disease, but little is known about its consequences in terms of parkinsonian manifestations. Here, we evaluated two aspects of the noradrenergic system using multimodal in vivo imaging in patients with Parkinson's disease and healthy controls: the pigmented cell bodies of the locus coeruleus with neuromelanin sensitive MRI; and the density of α2-adrenergic receptors (ARs) with PET using 11C-yohimbine. Thirty patients with Parkinson's disease and 30 age- and sex-matched healthy control subjects were included. The characteristics of the patients' symptoms were assessed using the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS). Patients showed reduced neuromelanin signal intensity in the locus coeruleus compared with controls and diminished 11C-yohimbine binding in widespread cortical regions, including the motor cortex, as well as in the insula, thalamus and putamen. Clinically, locus coeruleus neuronal loss was correlated with motor (bradykinesia, motor fluctuations, tremor) and non-motor (fatigue, apathy, constipation) symptoms. A reduction of α2-AR availability in the thalamus was associated with tremor, while a reduction in the putamen, the insula and the superior temporal gyrus was associated with anxiety. These results highlight a multifaceted alteration of the noradrenergic system in Parkinson's disease since locus coeruleus and α2-AR degeneration were found to be partly uncoupled. These findings raise important issues about noradrenergic dysfunction that may encourage the search for new drugs targeting this system, including α2-ARs, for the treatment of Parkinson's disease.
Topics: Humans; Parkinson Disease; Tremor; Carbon Radioisotopes; Positron-Emission Tomography; Norepinephrine; Locus Coeruleus; Magnetic Resonance Imaging; Melanins
PubMed: 37787503
DOI: 10.1093/brain/awad338