Protein Deposition Research Articles

Probing effects of site-specific aspartic acid isomerization on structure and stability of GB1 through chemical protein synthesis.

Chemical modifications of long-lived proteins, such as isomerization and epimerization, have been evoked as prime triggers for protein-damage related diseases. Deamidation of Asn residues, which results in formation of a mixture of l- and d-Asp and isoAsp via an intermediate aspartyl succinimide, can result in the disruption of cellular proteostasis and toxic protein depositions. In contrast to extensive data on the biological prevalence and functional implications of aspartyl succinimide formation, much less is known about the impact of the resulting altered backbone composition on properties of individual proteins at a molecular level. Here, we report the total chemical synthesis, biophysical characterization, and NMR structural analysis of a series of variants of the B1 domain of protein G from Streptococcal bacteria (GB1) in which all possible Asp isomers as well as an aspartyl succinimide were individually incorporated at a defined position in a solvent-exposed loop. Subtle local structural effects were observed; however, these were accompanied by notable differences in thermodynamic folded stability. Surprisingly, the noncanonical backbone connectivity of d-isoAsp led to a variant that exhibited enhanced stability relative to the natural protein.

Thyroid dysfunction and Alzheimer's disease, a vicious circle.

Recently, research into the link between thyroid dysfunction and Alzheimer's disease (AD) remains a current topic of interest. Previous research has primarily concentrated on examining the impact of thyroid dysfunction on the risk of developing AD, or solely explored the mechanisms of interaction between hypothyroidism and AD, a comprehensive analysis of the mechanisms linking thyroid dysfunction, including hyperthyroidism and hypothyroidism, to Alzheimer's disease (AD) still require further elucidation. Therefore, the aim of this review is to offer a thorough and comprehensive explanation of the potential mechanisms underlying the causal relationship between thyroid dysfunction and AD, highlighting the existence of a vicious circle. The effect of thyroid dysfunction on AD includes neuron death, impaired synaptic plasticity and memory, misfolded protein deposition, oxidative stress, and diffuse and global neurochemical disturbances. Conversely, AD can also contribute to thyroid dysfunction by affecting the stress repair response and disrupting pathways involved in thyroid hormone (TH) production, transport, and activation. Furthermore, this review briefly discusses the role and significance of utilizing the thyroid as a therapeutic target for cognitive recovery in AD. By exploring potential mechanisms and therapeutic avenues, this research contributes to our understanding and management of this devastating neurodegenerative disease.

Multiscale modelling of biomolecular corona formation on metallic surfaces.

In the realm of food industry, the choice of non-consumable materials used plays a crucial role in ensuring consumer safety and product quality. Aluminum is widely used in food packaging and food processing applications, including dairy products. However, the interaction between aluminum and milk content requires further investigation to understand its implications. In this work, we present the results of multiscale modelling of the interaction between various surfaces, that is (100), (110), and (111), of fcc aluminum with the most abundant milk proteins and lactose. Our approach combines atomistic molecular dynamics, a coarse-grained model of protein adsorption, and kinetic Monte Carlo simulations to predict the protein corona composition in the deposited milk layer on aluminum surfaces. We consider a simplified model of milk, which is composed of the six most abundant milk proteins found in natural cow milk and lactose, which is the most abundant sugar found in dairy. Through our study, we ranked selected proteins and lactose adsorption affinities based on their corresponding interaction strength with aluminum surfaces and predicted the content of the naturally forming biomolecular corona. Our comprehensive investigation sheds light on the implications of aluminum in food processing and packaging, particularly concerning its interaction with the most abundant milk proteins and lactose. By employing a multiscale modelling approach, we simulated the interaction between metallic aluminum surfaces and the proteins and lactose, considering different crystallographic orientations. The results of our study provide valuable insights into the mechanisms of lactose and protein deposition on aluminum surfaces, which can aid in the general understanding of protein corona formation.

Effect of the aggregated protein dye YAT2150 on Leishmania parasite viability.

The problems associated with the drugs currently used to treat leishmaniasis, including resistance, toxicity, and the high cost of some formulations, call for the urgent identification of new therapeutic agents with novel modes of action. The aggregated protein dye YAT2150 has been found to be a potent antileishmanial compound, with a half-maximal inhibitory concentration (IC50) of approximately 0.5 µM against promastigote and amastigote stages of Leishmania infantum. The encapsulation in liposomes of YAT2150 significantly improved its in vitro IC50 to 0.37 and 0.19 µM in promastigotes and amastigotes, respectively, and increased the half-maximal cytotoxic concentration in human umbilical vein endothelial cells to >50 µM. YAT2150 became strongly fluorescent when binding intracellular protein deposits in Leishmania cells. This fluorescence pattern aligns with the proposed mode of action of this drug in the malaria parasite Plasmodium falciparum, the inhibition of protein aggregation. In Leishmania major, YAT2150 rapidly reduced ATP levels, suggesting an alternative antileishmanial mechanism. To the best of our knowledge, this first-in-class compound is the only one described so far having significant activity against both Plasmodium and Leishmania, thus being a potential drug for the treatment of co-infections of both parasites.

Enhanced antifouling and separation capabilities of polydopamine@Ce-MOF functionalized PES ultrafiltration membrane

The need for antifouling membranes is substantial due to fouling’s negative impact on the effectiveness and durability of ultrafiltration membranes. In recent times, Metal-Organic Frameworks (MOFs) have emerged as effective additives for crafting ultrafiltration (UF) membranes. However, to harness their benefits and mitigate their drawbacks, a well-considered approach is imperative. In this work, polyethersulfone (PES) UF membranes were tailored with polydopamine (PDA)-modified cerium (Ce)-MOF (PDA@Ce-MOF) to achieve satisfactory antifouling properties and to remove biological macromolecules such as bovine serum albumin (BSA) and humic acid (HA) from wastewater. The non-solvent induced phase separation (NIPS) method was used to simultaneously fabricate the membrane and modify it with different PDA@Ce-MOF concentrations ranging from 0.05 to 0.50 wt.%. Results showed significant improvements on the membrane’s morphology, hydrophilicity, porosity and pore size at 0.10 wt.% loading of PDA@Ce-MOF. The synergistic effect of the PDA and Ce-MOF on the membrane improved the pure water flux (337 L m−2 h−1) and filtration performance in the filtration of Bovine serum albumin (BSA) and humic acid (HA) reporting 145 L m−2 h−1 and 98% rejection, and 164 L m−2 h−1 and 88% rejection; respectively. Further, water-attracting functional moieties of PDA@Ce-MOF hindered the deposition of BSA protein on the membrane surface, resulting in an excellent flux recovery ratio (FRR) of ~87%, alongside mitigated irreversible fouling.

Futoquinol improves Aβ25-35-induced memory impairment in mice by inhibiting the activation of p38MAPK through the glycolysis pathway and regulating the composition of the gut microbiota.

Futoquinol (Fut) is a compound extracted from Piper kadsura that has a nerve cell protection effect. However, it is unclear whether Fut has protective effects in Alzheimer's disease (AD). In this study, we aimed to explore the therapeutic effect of Fut in AD and its underlying mechanism. UPLC-MS/MS method was performed to quantify Fut in the hippocampus of mice brain. The cognition ability, neuronal and mitochondria damage, and levels of Aβ1-42, Aβ1-40, p-Tau, oxidative stress, apoptosis, immune cells, and inflammatory factors were measured in Aβ25-35-induced mice. The content of bacterial meta-geometry was predicted in the microbial composition based on 16S rDNA. The protein levels of HK II, p-p38MAPK, and p38MAPK were detected. PC-12 cells were cultured in vitro, and glucose was added to activate glycolysis to further explore the mechanism of action of Fut intervention in AD. Fut improved the memory and learning ability of Aβ25-35 mice, and reduced neuronal damage and the deposition of Aβ and Tau proteins. Moreover, Fut reduced mitochondrial damage, the levels of oxidative stress, apoptosis, and inflammatory factors. Fut significantly inhibited the expression of HK II and p-p38MAPK proteins. The in vitro experiment showed that p38MAPK was activated and Fut action inhibited after adding 10 mM glucose. Fut might inhibit the activation of p38MAPK through the glycolysis pathway, thereby reducing oxidative stress, apoptosis, and inflammatory factors and improving Aβ25-35-induced memory impairment in mice. These data provide pharmacological rationale for Fut in the treatment of AD.

Hippocampus and jejunum biochemical parameters related to physiological ageing of neurons in rats fed diets with copper nanoparticles and different fiber types

Abstract One of the more important factors responsible for synaptic dysfunction of neurons is a neurological ageing. It is a natural consequence of occurrence of biochemical pathways in cells, promoting oxidation processes, an increase in the amount of free oxygen radicals that damage DNA, disorders in calcium ion homeostasis, interactions between lipids of cell membranes, formation of neurofibrillary tangles and deposition of toxic protein deposits. Diet modifications can delay neurometabolism disorders that occur as a result of aging, as well as limit the development of neurodegenerative diseases. The aim of this study on rats was to verify the hypothesis regarding the effect of dietary addition of copper nanoparticles (CuNPs; instead of standard CuCO3) in combination with various dietary fibers on changes in hippocampus and jejunum biochemical parameters related to metabolic disorders appearing with neurological ageing in rats. Male rats were fed a control diet with containing fiber α-cellulose and a standard or enhanced content of Cu provided as CuCO3 (6.5 or 13 mg/kg diet). The diets of other groups were deprived of CuCO3 and the animals were fed diets supplemented with two CuNPs aforementioned doses, and additionally combined with four different types of dietary fiber: α-cellulose (control fiber), pectin, inulin or psyllium (Plantago psyllium). The addition of dietary CuNPs increased the level of acetylcholinesterase (AChE) and decreased the levels of Tau protein, glycosylated AChE (GAChE) and Ca/calmodulin dependent protein kinase II alpha (CAMK2α) in the examined organs. To sum up, both applied doses of CuNPs, 6.5 mg and 13 mg per kg of a diet, can beneficially modulate some important parameters describing metabolic and neurodevelopmental status in the hippocampal and small intestinal tissue of rats. With regard to the fiber type added to rats’ diet, the Plantago psyllium fiber strengthened the mentioned effects of copper nanoparticles. The observed effects should be confirmed in a model study of neurodegeneration.

Addition of α-ketoglutaric acid (AKG) reduces deamination in Chinese perch (Siniperca chuatsi) fed with fermented soybean meal as a substitute for fishmeal.

To alleviate amino acid imbalances in fermented soybean meal as a replacement for fishmeal feeds, this study evaluated the effects of adding lysine (Lys), methionine (Met), and α-ketoglutaric acid (AKG) to fermented soybean meals for Chinese perch. Chinese perch (34 ± 3g) were fed five diets for 66days (fishmeal as the protein source of the basal diet [FM]; fermented soybean meal as a substitute for 30% fishmeal in the soybean meal diet [FSM]; addition of crystalline Lys and Met [AA]; addition of α-ketoglutaric acid [AKG]; and simultaneous addition of crystalline Lys, Met, and AKG [BA] to the soybean meal diet). At the end of the feeding trial, the FSM group had the highest feeding rate and the lowest weight gain rate among all the groups. The FM group had the highest protein retention and the lowest feed efficiency among the groups. The mRNA transcription level of genes related to the AMP-activating protein (AMPK) signaling pathway and amino acid response (AAR) signaling pathway (lkb1, atf4, and gcn2) were highest in the AA group (P < 0.05) but lower in the AKG and BA groups. In the AKG group, the mRNA transcription level of the gluconeogenesis pathway-related gene (pepck and g6pase) was significantly higher than that in the other four groups, but the mRNA transcription level of genes related to amino acid catabolism (gdh and ampd) was lower. Among all the groups, the FSM group had the lowest mRNA transcription level of genes associated with the mammalian target of rapamycin (mTOR) signaling pathway (mtor and s6k). These findings imply that the feeding rate of Chinese perch in the fermented soybean meal group was the highest, but the protein retention was the lowest, while the addition of Lys, Met, and AKG improved protein retention. In conclusion, the addition of AKG to fermented soybean meal as a fishmeal substitute reduced amino acid deamination, enhanced gluconeogenesis, and increased protein deposition, which contributed to the growth of Chinese perch, alleviated amino acid imbalances, and improved the feed utilization of Chinese perch.

Comparison of Lysophospholipids and Bile Acids on the Growth Performance, Lipid Deposition, and Intestinal Health of Largemouth Bass (Micropterus salmoides)

Lysophospholipids (LPLs) and bile acids (BA) are commonly used as emulsifiers in aquaculture. This study investigated the effects of dietary supplementation of LPLs or BA on the growth performance, lipid deposition, and intestinal health of largemouth juveniles. Fish were randomly allotted into three groups in quadruplicate and fed with a basal diet (CON) or diets containing 300 mg/kg LPLs (LPLs), or 300 mg/kg commercially available BA product (BA) for 8 weeks. The results showed that compared with the control group, LPLs and BA supplemented groups showed a higher weight gain trend, and LPLs supplementation promoted the protein deposition in fish body. Both BA and LPLs supplementations helped to maintain liver health by decreasing the activities of aspartate aminotransferase and alanine aminotransferase in serum. Besides, LPLs supplementation decreased overall lipid deposition in terms of mesenteric fat index and liver lipid content. Furthermore, LPLs supplementation showed unique advantage in improving intestinal barrier, as characterized by the increased villus length and higher expression of the tight junction protein zo-1 expression. LPLs supplementation also increased the alpha diversity index and the abundances of Proteobacteria in the intestinal microbiota which is positively correlated with the abundance of SCFA in the gut. These findings will promote the application of novel feed additives and especially provide a basis for the rational selection of emulsifiers in the aquaculture industry.

Epigenetic Priming Enhances Chondrogenic Potential of Expanded Chondrocytes.

Expansion of chondrocytes presents a major obstacle in the cartilage regeneration procedure, such as matrix-induced autologous chondrocyte implantation. Dedifferentiation of chondrocytes during the expansion process leads to the emergence of a fibrotic (chondrofibrotic) phenotype that decreases the chondrogenic potential of the implanted cells. We aim to (1) determine the extent that chromatin architecture of H3K27me3 and H3K9me3 remodels during dedifferentiation and persists after the transfer to a three-dimensional (3D) culture; and (2) to prevent this persistent remodeling to enhance the chondrogenic potential of expanded bovine chondrocytes, used as a model system. Chromatin architecture remodeling of H3K27me3 and H3K9me3 was observed at 0 population doublings, 8 population doublings, and 16 population doublings (PD16) in a two-dimensional (2D) culture and after encapsulation of the expanded chondrocytes in a 3D hydrogel culture. Chondrocytes were treated with inhibitors of epigenetic modifiers (epigenetic priming) for PD16 and then encapsulated in 3D hydrogels. Chromatin architecture of chondrocytes and gene expression were evaluated before and after encapsulation. We observed a change in chromatin architecture of epigenetic modifications H3K27me3 and H3K9me3 during chondrocyte dedifferentiation. Although inhibiting enzymes that modify H3K27me3 and H3K9me3 did not alter the dedifferentiation process in 2D culture, applying these treatments during the 2D expansion did increase the expression of select chondrogenic genes and protein deposition of type II collagen when transferred to a 3D environment. Overall, we found that epigenetic priming of expanded bovine chondrocytes alters the cell fate when chondrocytes are later encapsulated into a 3D environment, providing a potential method to enhance the success of cartilage regeneration procedures.

Macromolecular Crowding Enhances Matrix Protein Deposition in Tissue-Engineered Vascular Grafts.

Successful in vitro culture of small-diameter tissue-engineered vascular grafts (TEVGs) requires rapid deposition of biomacromolecules secreted by vascular smooth muscle cells in a polyglycolic acid mesh scaffold's three-dimensional (3D) porous environment. However, common media have lower crowding conditions than in vivo tissue fluids. In addition, during the early stages of construction, most of the biomolecules secreted by the cells into the medium are lost, which negatively affects the TEVG culture process. In this study, we propose the use of macromolecular crowding (MMC) to enhance medium crowding to improve the deposition and self-assembly efficiency of major biomolecules in the early stages of TEVG culture. The addition of carrageenan significantly increased the degree of MMC in the culture medium without affecting cell viability, proliferation, and metabolic activity. Protein analysis demonstrated that the deposition of collagen types I and III and fibronectin increased significantly in the cell layers of two-dimensional and 3D smooth muscle cell cultures after the addition of a MMC agent. Collagen type I in the culture medium decreased significantly compared with that in the medium without a MMC agent. Scanning electron microscopy demonstrated that MMC agents considerably enhanced the formation of matrix protein structures during the early stages of 3D culture. Hence, MMC modifies the crowding degree of the culture medium, resulting in the rapid formation of numerous matrix proteins and fiber structures. Impact Statement Small-diameter tissue-engineered vascular grafts (TEVGs) are one of the most promising means of treating cardiovascular diseases; however, the in vitro construction of TEVGs has some limitations, such as slow deposition of extracellular matrix (ECM), long culture period, and poor mechanical properties. We hypothesized that macromolecular crowding can increase the crowding of the culture medium to construct a more bionic microenvironment, which enhances ECM deposition in the medium to the cell layer and reduces collagen loss, accelerating and enhancing TEVG culture and construction in vitro.

TMEM16A inhibits renal tubulointerstitial fibrosis via Wnt/β-catenin signaling during hypertension nephropathy

Background and objectiveHypertensive nephropathy is the second leading cause of end-stage renal disease, but its underlying pathogenesis remains unclear. Therefore, this study aimed to explore whether transmembrane protein 16 A (TMEM16A), the molecular basis of calcium-activated chloride channels (CaCC), is involved in the development and progression of hypertensive nephropathy. MethodsIn vivo and in vitro experiments were conducted using a hypertensive murine model and human kidney proximal tubular epithelial cells (HK-2 cells), respectively. Experimental resultsThe expression of TMEM16A was down-regulated in renal samples of hypertensive nephropathy patients and hypertensive model mice, accompanied by excessive deposition of extracellular matrix proteins (ECM) such as Fibronectin, Laminin, Collagen I and Collagen III, the up-regulation of α-smooth muscle actin (α-SMA) expression, and the decrease of E-cadherin. Overexpression of TMEM16A or knockdown of TMEM16A inhibited or promoted the expression of Wnt/β-catenin signaling pathway proteins Wnt3a, LRP5 and active β-catenin in HK-2 cells, preventing the epithelial-to-mesenchymal transition (EMT) of renal tubules, and the synthesis of ECM components. ConclusionIn angiotensin II (Ang II)-induced hypertensive nephropathy, TMEM16A was identified as a key player inhibiting the detrimental changes in renal tubules, suggesting a potential avenue for mitigating renal damage in hypertensive nephropathy.

Obstructive sleep apnea affects cognition: dual effects of intermittent hypoxia on neurons.

Obstructive sleep apnea (OSA) is a common respiratory disorder. Multiple organs, especially the central nervous system (CNS), are damaged, and dysfunctional when intermittent hypoxia (IH) occurs during sleep for a long time. The quality of life of individuals with OSA is significantly impacted by cognitive decline, which also escalates the financial strain on their families. Consequently, the development of novel therapies becomes imperative. IH induces oxidative stress, endoplasmic reticulum stress, iron deposition, and neuroinflammation in neurons. Synaptic dysfunction, reactive gliosis, apoptosis, neuroinflammation, and inhibition of neurogenesis can lead to learning and long-term memory impairment. In addition to nerve injury, the role of IH in neuroprotection was also explored. While causing neuron damage, IH activates the neuronal self-repairing mechanism by regulating antioxidant capacity and preventing toxic protein deposition. By stimulating the proliferation and differentiation of neural stem cells (NSCs), IH has the potential to enhance the ratio of neonatal neurons and counteract the decline in neuron numbers. This review emphasizes the perspectives and opportunities for the neuroprotective effects of IH and informs novel insights and therapeutic strategies in OSA.

Black soldier fly (Hermetia illucens) larvae meal improves quail growth performance.

The aim of the present study was to determine the nutritional value of black soldier fly (BSF) larvae meal for quail (experiment I) and the dose-response effects of BSF levels on growth performance, relative organ weight, and body composition of growing quails (experiment II). In experiment I, 100 35-day-old quail were distributed in a completely randomized design, with two treatments (reference and test diet) and 10 replicates. The experimental period consisted of 5days of adaptation, followed by 5days of total excreta collection. The experimental feed consisted of a reference diet and a test diet formulated with 850g/kg reference diet and 150g/kg BSF. In experiment II, 1000 1-day-old quail were distributed in a completely randomized design, with five dietary levels of BSF (0, 25, 50, 75, and 100g/kg). At 42days of age, birds were slaughtered, and the relative organ weight and body composition were determined. Apparent metabolizable energy values corrected for nitrogen retention of BSF meal were 13.8MJ/kg. Across the starter (1-14days) and overall period (1-42days), increasing BSF levels had a quadratic effect on body weight and body weight gain. Feed conversion ratio was quadratically affected during the starter phase and linearly reduced over the overall period. Additionally, the BSF levels linearly decreased the small intestine's relative weight at 42days and had a quadratic effect on the rate of protein deposition. We concluded that the inclusion of 100g/kg BSF meal improves feed conversion ratio for growing quail.

The amino acid pattern and dynamics of body protein, body fat deposition in male and female broilers under different temperatures

The present study was conducted 1) to investigate the effects of gender and temperature on growth performance in broiler chickens and 2) to establish body protein and fat deposition curves and amino acid patterns for broilers of both genders at different ambient temperatures. A total of 432 1-day-old (d) Arbor Acres chickens with a male/female ratio of 1:1 were randomly divided into the following 4 treatment groups: the male thermoneutral group, the female thermoneutral group, the male heat stress group, and the female heat stress group. The chickens in the thermoneutral groups were kept at a comfortable temperature from 1 to 42 d, while chickens in the heat stress groups were kept at a comfortable temperature from 1 to 28 d and at a high ambient temperature from d 29 to 42. The body composition retention data were obtained by comparative slaughter method, and the models were constructed by the Gompertz model. The results revealed significant variation in body protein content (BPC) and body fat deposition efficiency (BFE) between both genders and the 2 temperatures. Moreover, a noteworthy interaction between gender and temperature was observed in terms of the BPC and protein deposition efficiency (BPE). The following equations for body protein and body fat deposition in the thermoneutral groups were obtained: Body protein weight of male broilers: [Formula: see text] ; Body protein weight of female broilers: [Formula: see text] ; Body fat weight of male broilers: [Formula: see text] ; Body fat weight of female broilers: [Formula: see text] . Where t means age (d). The following equations for body protein and body fat deposition in the heat stress groups were obtained: Body protein weight of male broilers: [Formula: see text] ; Body protein weight of female broilers: [Formula: see text] ; Body fat weight of male broilers: [Formula: see text] ; Body fat weight of female broilers: [Formula: see text] . Where t means age (d). In addition, no significant difference in amino acid content was found between different genders and temperatures. The amino acid pattern could be divided into 2 stages: 0 to 14 d and 15 to 42 d. Our equations and patterns enable a deeper understanding of the nutritional requirements in broiler chickens under various temperature conditions. This enables researchers to develop more accurate feeding programs to fulfill the growth and health requirements of broiler chickens.

Diagnostic problems of rare diseases - amyloidosis. A case report

The presented case study focuses on the complexities and challenges in diagnosingone of the forms of amyloidosis, where abnormal protein (amyloid) deposits in variousorgans and tissues lead to affection of many organs, especially the heart, kidneys, liver,spleen, and occasionally the central nervous system. Its aetiology remains largely unknown,making diagnosis and treatment particularly challenging.This report details the case of an 88-year-old patient, disabled for months (with amodified Rankin Scale score of 4), who presented to the Neurology Department with suddenright limb paresis and speech disorders. Initial assessments indicated suggested ischemicstroke, and patients received thrombolysis. Further laboratory tests and imaging, includingserum protein electrophoresis and computer tomograph (CT) scans, suggested transthyretinamyloidosis (ATTR), which was later confirmed through genetic testing.This case underscores the rapid, multi-organ progression of amyloidosis and itsdevastating impact, highlighting the necessity for early diagnosis and a multidisciplinarytreatment approach.Despite ongoing research, the pathogenesis of amyloidosis remains elusive, andcurrent treatment options are primarily symptomatic. This study aims to shed light on thediagnostic difficulties and the urgent need for timely intervention in amyloidosis cases.

Probing the microstructure of pathological protein deposits in Alzheimer’s disease

Probing the microstructure of pathological protein deposits in Alzheimer’s disease

Efficacy of topical gabapentin in women with primary macular amyloidosis: A side-by-side triple-blinded randomized clinical trial.

Primary cutaneous macular amyloidosis (PCMA) is a chronic pruritic cutaneous disease characterized by heterogeneous extracellular deposition of amyloid protein in the skin. This study aimed to evaluate the efficacy of topical 6% gabapentin cream for the treatment of patients with PCMA. In this triple-blind clinical trial, a total of 34 patients, who were diagnosed with PCMA, treated using two different strategies of topical gabapentin as the active group and vehicle cream as the control group. Pruritus score reduction in both groups was statistically significant compared with the baseline value (p < 0.001). There was a significant pigmentation score reduction in intervention group compared with control group after 1 month of the study (p < 0.001). The differences of pigmentation score changes between the groups were not significant at month 2 (p = 0.52) and month 3 (p = 0.22). The results of this study suggest that topical gabapentin cream may be effective as a topical agent in the treatment of pruritus associated with PCMA without any significant adverse effects. It is recommended to perform similar studies with a larger sample size and longer duration in both sexes.

A case of bilateral amyloidosis localized to extraocular muscles mimicking thyroid eye disease

BackgroundAmyloidosis is a rare condition characterized by the abnormal deposition of amyloid proteins in various tissues and organs. While systemic amyloidosis has been well-documented, amyloid deposition in extraocular muscles is an exceptionally rare occurrence, with only 35 reported cases. This case report sheds light on the importance of considering amyloidosis in the differential diagnosis of patients presenting with proptosis and diplopia, which are often associated with thyroid eye disease.Case presentationA woman in her twenties sought medical attention due to a complaint of diplopia. Her ocular examination revealed almost normal findings except for exotropia and proptosis. Orbital magnetic resonance imaging displayed fusiform enlargement of nearly all eye muscles, a presentation typically observed in thyroid eye disease. However, despite corticosteroid therapy, her symptoms showed no improvement. Given the unusual lack of response to conventional treatment, and inhomogeneous enhancement of the muscle, an extraocular muscle biopsy was conducted. This biopsy yielded a unique finding—amyloid deposition within the muscle tissue. This discovery was particularly intriguing due to the extreme rarity of amyloidosis affecting extraocular muscles, with fewer than three dozen documented cases worldwide.ConclusionThis unique case underscores the critical need for a comprehensive approach to diagnosing patients with proptosis and diplopia. While these symptoms are commonly attributed to thyroid eye disease, it is essential to consider alternative diagnoses such as amyloidosis, especially when standard treatments fail to yield results. The discovery of amyloid deposition in the extraocular muscles, although exceedingly rare, emphasizes the significance of a thorough differential diagnosis. In conclusion, this case report highlights the importance of vigilance in clinical practice, encouraging ophthalmologists to explore less common diagnostic possibilities when faced with challenging cases. Further research and clinical investigation are warranted to better understand the mechanisms and potential treatments for amyloidosis affecting the extraocular muscles.

Developmental morphogens direct human induced pluripotent stem cells toward an annulus fibrosus-like cell phenotype.

Therapeutic interventions for intervertebral disc herniation remain scarce due to the inability of endogenous annulus fibrosus (AF) cells to respond to injury and drive tissue regeneration. Unlike other orthopedic tissues, such as cartilage, delivery of exogenous cells to the site of annular injury remains underdeveloped, largely due to a lack of an ideal cell source and the invasive nature of cell isolation. Human induced pluripotent stem cells (iPSCs) can be differentiated to specific cell fates using biochemical factors and are, therefore, an invaluable tool for cell therapy approaches. While differentiation protocols have been developed for cartilage and fibrous connective tissues (e.g., tendon), the signals that regulate the induction and differentiation of human iPSCs toward the AF fate remain unknown. iPSC-derived sclerotome cells were treated with various combinations of developmental signals including transforming growth factor beta 3 (TGF-β3), connective tissue growth factor (CTGF), platelet derived growth factor BB (PDGF-BB), insulin-like growth factor 1 (IGF-1), or the Hedgehog pathway activator, Purmorphamine, and gene expression changes in major AF-associated ECM genes were assessed. The top performing combination treatments were further validated by using three distinct iPSC lines and by assessing the production of upregulated ECM proteins of interest. To conduct a broader analysis of the transcriptomic shifts elicited by each factor combination, and to compare genetic profiles of treated cells to mature human AF cells, a 96.96 Fluidigm gene expression array was applied, and principal component analysis was employed to identify the transcriptional signatures of each cell population and treatment group in comparison to native AF cells. TGF-β3, in combination with PDGF-BB, CTGF, or IGF-1, induced an upregulation of key AF ECM genes in iPSC-derived sclerotome cells. In particular, treatment with a combination of TGF-β3 with PDGF-BB for 14 days significantly increased gene expression of collagen II and aggrecan and increased protein deposition of collagen I and elastin compared to other treatment groups. Assessment of genes uniquely highly expressed by AF cells or SCL cells, respectively, revealed a shift toward the genetic profile of AF cells with the addition of TGF-β3 and PDGF-BB for 14 days. These findings represent an initial approach to guide human induced pluripotent stem cells toward an AF-like fate for cellular delivery strategies.