Comprehensive review of ASC structure and function in immune homeostasis and disease.

Apoptosis associated speck like protein containing CARD (ASC) is widely researched and recognized as an adaptor protein participating in inflammasome assembly and pyroptosis. It contains a bipartite structure comprising of a pyrin and a caspase recruitment domain (CARD) domain. These two domains help ASC function as an adaptor molecule. ASC is encoded by the gene PYCARD. ASC plays pivotal role in various diseases as well as different homeostatic processes. ASC plays a regulatory role in different cancers showing differential regulation with respect to tissue and stage of disease. Besides cancer, ASC also plays a central role in sensing, regulation, and/or disease progression in bacterial infections, viral infections and in varied inflammatory diseases. ASC is expressed in different types of immune and non-immune cells. Its localization pattern also varies with different kinds of stimuli encountered by cell. This review will summarize the literature on the structure cellular and tissue expression, localization and disease association of ASC.

Stewart-Treves Syndrome in the Lower Limb after Arthroplasty- A Case Report.

Stewart-Treves Syndrome is a rare and fatal condition where cutaneous angiosarcoma-a high-grade malignant tumor originating in the vascular and lymphatic endothelium-classically develops in the upper limbs post-mastectomy, with radiation therapy and axillary lymph node dissection. There are very few reports of the syndrome developing in the lower limbs, without any preceding malignancy or radiation therapy. The median development time is 11 years. Angiosarcoma originates in the vascular and lymphatic vessels, and the diagnosis is based on histopathology and immunohistochemistry findings. We report an unusual presentation of the Stewart-Treves Syndrome in an elderly female involving the lower limb with preexisting chronic lymphedema, where the tumor developed 15 months after total knee arthroplasty.

10% Thioglycolic Acid Peel in the Treatment of Pigmented Purpuric Dermatoses: A Pilot Study.

Pigmentary purpuric dermatosis (PPD) is a chronic dyspigmentation characterized by reddish-brown, irregular maculae with dermal hemosiderin deposition, usually affecting the legs. The -SH group in the thioglycolic acid (TGA) strongly binds to iron molecule, solubilizes it, and clears the pigment. We conducted a longitudinal, right-left leg study for assessing the effectiveness and side effects of TGA 10% peel in treating PPD. For preparation of 10% TGA peel, 80% TGA was diluted with distilled water to 10% concentration by mixing 0.5 mL of acid with 3.5 mL of water before every peel session. The peel was applied on the left leg, weekly for 6 weeks. Assessment was done at baseline and at weeks 3 and 6. Any improvement was noted by the patient and another independent dermatologist. The right leg was untreated. Any side effects during peel application and afterwards were noted. According to the patient assessment, 4/10 patients observed mild improvement, 5/10 patients had moderate improvement, and only a single patient had marked improvement. In the physician assessment, 2/10 patients had >50% improvement, 5/10 patients had 30-40% improvement, and 3/10 patients had 10-20% improvement. Side effects included slight burning during application and foul odor. A single patient had intense erythema and mild swelling of the leg after peel application. 10% TGA is effective in the partial clearance of PPD dyspigmentation with weekly sessions for 6 weeks without any serious side effects.

Treating Vitiligo at the Angle of Lips: A Narrative Review.

Vitiligo is a common autoimmune depigmentary disorder seen among Indian patients. It has a significant impact on the self-esteem of the patient. Specific sites including acral areas, joints, and lips are usually resistant to medical therapy and thus transfer of melanocytes is mandatory for the treatment. Vitiligo at the angle of lips is distinct from the vitiligo on other sites, with respect to response to therapy, lack of hair follicles, and high mobility of the area. Our aim was to review the various therapeutic modalities available for the treatment of vitiligo at this site. In our narrative review, we searched databases including PubMed, Google Scholar, and EBSCO with a full strategic search with keywords "Vitiligo," "leucoderma," "mucosal vitiligo," "lips," "labial," "angle of lips," "Minipunch grafting," "Suction Blister epidermal Grafting," "SBEG," "Micropigmentation," "tattooing," and "Excision" from 2005 to 2021. The relevant articles were extracted and included in the review. Various modalities including suction blister grafting, miniature punch grafting, split-thickness grafting, and micropigmentation have been reviewed with their advantages and disadvantages. Various potential modalities of therapy have also been proposed in the review.

Dopamine induces functional extracellular traps in microglia.

Dopamine (DA) plays many roles in the brain, especially in movement, motivation, and reinforcement of behavior; however, its role in regulating innate immunity is not clear. Here, we show that DA can induce DNA-based extracellular traps in primary, adult, human microglia and BV2 microglia cell line. These DNA-based extracellular traps are formed independent of reactive oxygen species, actin polymerization, and cell death. These traps are functional and capture fluorescein (FITC)-tagged Escherichia coli even when reactive oxygen species production or actin polymerization is inhibited. We show that microglial extracellular traps are present in Glioblastoma multiforme. This is crucial because Glioblastoma multiforme cells are known to secrete DA. Our findings demonstrate that DA plays a significant role in sterile neuro-inflammation by inducing microglia extracellular traps.

Protocol for induction and characterization of microglia extracellular traps in murine and human microglia cells.

Extracellular traps (ETs) are composed of decondensed chromatin and are embedded with various antimicrobial proteins like myeloperoxidase and histones. Recently, we reported that dopamine (DA) induces ETs in BV2 microglia cell line and primary adult human microglia in a manner independent of cell death, reactive oxygen species, and actin polymerization. This protocol details how to characterize DA-induced ETs in BV2 microglia and human microglia. The protocols for characterization of ETs may also be used for other adherent cell lines. For complete details on the use and execution of this protocol, please refer to Agrawal et al. (2021).

Mitochondrial Dysfunction and Alzheimer's Disease: Role of Microglia.

In 1907, Alois Alzheimer observed, as he quoted, development of "numerous fibers" and "adipose saccules" in the brain of his diseased patient Auguste Deter. The neurodegenerative disease became known as Alzheimer's disease (AD) and is the most common cause of dementia worldwide. AD normally develops with aging and is mostly initiated because of the imbalance between the formation and clearance of amyloid-ß (Aß). Formation of neurofibrillary tangles (NFTs) of hyperphosphorylated tau is another hallmark of AD. Neuroinflammation plays a significant role in the development and pathology of AD. This chapter explores the role of mitochondrial dysfunction in microglia in case of AD. Mitochondrial oxidative stress in microglia has been linked to the development of AD. Elevated generation of reactive oxygen species (ROS) and loss of mitochondrial membrane potential through various mechanisms have been observed in AD. Aß interacts with microglial receptors, such as triggering receptor expressed in myeloid cells 2 (TREM2), activating downstream pathways causing mitochondrial damage and aggravating inflammation and cytotoxicity. Fibrillar Aß activates nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in microglia leading to elevated induction of mitochondrial ROS which further causes neurotoxicity. Elevated ROS in microglia causes activation of inflammatory and cell death pathways. Production of ATP, regulation of mitochondrial health, autophagy, and mitophagy in microglia play significant roles in the AD pathology. Understanding microglial physiology and mitochondrial dysfunction will enable better therapeutic interventions.

Obtaining Human Microglia from Adult Human Brain Tissue.

Microglia are resident innate immune cells of the central nervous system (CNS). Microglia play a critical role during development, in maintaining homeostasis, and during infection or injury. Several independent research groups have highlighted the central role that microglia play in autoimmune diseases, autoinflammatory syndromes and cancers. The activation of microglia in some neurological diseases may directly participate in pathogenic processes. Primary microglia are a powerful tool to understand the immune responses in the brain, cell-cell interactions and dysregulated microglia phenotypes in disease. Primary microglia mimic in vivo microglial properties better than immortalized microglial cell lines. Human adult microglia exhibit distinct properties as compared to human fetal and rodent microglia. This protocol provides an efficient method for isolation of primary microglia from adult human brain. Studying these microglia can provide critical insights into cell-cell interactions between microglia and other resident cellular populations in the CNS including, oligodendrocytes, neurons and astrocytes. Additionally, microglia from different human brains may be cultured for characterization of unique immune responses for personalized medicine and a myriad of therapeutic applications.

Differential Expression Profile of NLRs and AIM2 in Glioma and Implications for NLRP12 in Glioblastoma.

Gliomas are the most prevalent primary brain tumors with immense clinical heterogeneity, poor prognosis and survival. The nucleotide-binding domain, and leucine-rich repeat containing receptors (NLRs) and absent-in-melanoma 2 (AIM2) are innate immune receptors crucial for initiation and progression of several cancers. There is a dearth of reports linking NLRs and AIM2 to glioma pathology. NLRs are expressed by cells of innate immunity, including monocytes, macrophages, dendritic cells, endothelial cells, and neutrophils, as well as cells of the adaptive immune system. NLRs are critical regulators of major inflammation, cell death, immune and cancer-associated pathways. We used a data-driven approach to identify NLRs, AIM2 and NLR-associated gene expression and methylation patterns in low grade glioma and glioblastoma, using The Cancer Genome Atlas (TCGA) patient datasets. Since TCGA data is obtained from tumor tissue, comprising of multiple cell populations including glioma cells, endothelial cells and tumor-associated microglia/macrophages we have used multiple cell lines and human brain tissues to identify cell-specific effects. TCGA data mining showed significant differential NLR regulation and strong correlation with survival in different grades of glioma. We report differential expression and methylation of NLRs in glioma, followed by NLRP12 identification as a candidate prognostic marker for glioma progression. We found that Nlrp12 deficient microglia show increased colony formation while Nlrp12 deficient glioma cells show decreased cellular proliferation. Immunohistochemistry of human glioma tissue shows increased NLRP12 expression. Interestingly, microglia show reduced migration towards Nlrp12 deficient glioma cells.