Sensory Innervation Research Articles

AURICULOTEMPORAL NERVE AND FREY'S SYNDROME

Background: The auriculotemporal nerve is one of the main branches of the mandibular nerve. It provides sensory innervation to the auricle, the scalp in the temporal region, the temporomandibular joint and part of the dura mater, the parasympathetic innervation of the parotid salivary gland, as well as the external surface of the tympanic membrane, and the sympathetic innervation of the sweat glands and of the blood vessels passing through the parotid gland. Its interruption during surgical interventions or trauma can results in its most common disease - Frey's syndrome. This article is an overview and is based on 23 foreign scientific works - articles published in refereed and renowned scientific publications and anatomy atlases by world-renowned and proven specialists in their field. Review Results: The auriculotemporal nerve is a sensory nerve which includes secretory parasympathetic vasomotor sympathetic fibers coming from the otic ganglion. It is a branch of the mandibular nerve (V3). Its five terminal nerve branches are front auricular branches, branches for the external auditory canal, branches for the temporomandibular joint, branches for the parotid gland and superficial temporal branches. Frey's syndrome occurs when the auriculotemporal nerve is cut or injured proximal to the site of separation of the branches for the parotid gland or are severed themselves. The clinical picture characteristic of Frey's syndrome includes redness, sweating, warmth and itching in the area of innervation of the nerve and less often pain. Conclusion: Knowledge of the anatomy of the auriculotemporal nerve and Frey's syndrome are essential for understanding its nature and stand on the basis of its prevention.

CNSC-38. CHARACTERIZATION OF THE FUNCTIONAL RELEVANCE OF INTRA- AND INTERTUMORAL NETWORKS IN PRIMARY BREAST CANCER

Abstract Despite intensive efforts to improve current therapeutical strategies, breast cancer continues to be a life-shortening diagnosis for a significant number of affected women. Considering that the innervation density of breast cancers negatively correlates with the prognosis, the emerging field of Cancer Neuroscience, which deals with the reciprocal interactions between the nervous system and cancer cells, represents an attractive novel research direction. In fact, studies on breast cancer brain metastases have proven that the metastatic cells receive growth stimuli by hijacking healthy glutamatergic synapses. Beyond being capable of forming direct glutamatergic cancer-neuron synapses, primary brain tumor cells also connect to a multicellular intercommunicating network that contributes to therapy resistance. Whether similar mechanisms also apply to tumors outside the brain – accountable for the majority of cancer cases – remains unknown. Here, we aim at unraveling the functional role of intratumoral networks and the influence of (potential) direct primary breast cancer cell-neuron interactions. We hypothesize that purinergic signaling as a universal synaptic signaling mechanism enhances tumor growth. Through the application of ex vivo whole-organ tissue-clearing and nerve-labeling approaches, we noticed prevalent sensory and sympathetic innervation in the healthy and diseased murine mammary gland. Furthermore, we measured tumor cell proliferation rates in an in vitro model of primary murine sensory DRG-neurons co-cultured with breast cancer stem cells and compared these to monoculture controls. By implanting a mammary imaging window over the growing primary tumor, we longitudinally track the calcium activity of breast cancer cells in their natural microenvironment in the living mouse. We thereby are able to record co-activity of neighboring cells indicative of intratumoral network communication in primary breast cancers. Overall, our data support the existence of functional intra- and intertumoral breast cancer cell networks as an alternative therapeutical target. Future work needs to concentrate on unequivocally detecting direct neuron-cancer cell contacts.

Partial Denervation of the Thumb Carpometacarpal Joint: A New Technique.

To report the clinical outcomes of partial denervation for the treatment of basilar thumb joint arthritis. Patients who underwent partial denervation of the basilar thumb joint for osteoarthritis from a single center between 2019 and 2021 were recruited into the study. This involved a technique that involved cauterization of the joint capsule and its innervation through the branches of the superficial radial, palmar cutaneous branch of the median, lateral antebrachial, and ulnar nerves. Patients were followed up postoperatively to record clinical (grip strength, thumb apposition and opposition pinch grip strength, Kapandji score) and patient-reported outcomes (visual analogue scale [VAS], Quick Disabilities of the Arm, Shoulder and Hand [QuickDASH], Patient-reported Wrist Evaluation [PRWE]). Twelve patients (15 carpometacarpal joints; 9 female and 3 male patients) underwent a partial denervation of the thumb (Eaton stage 3-4). The mean age at the time of surgery was 63 ± 5 years (range 56-72). The mean clinical follow-up duration was 23 ± 11 months (range 9-42 months), and functional score follow-up duration was 27 ± 7 months (range 14-42 months). At the latest clinical follow, VAS score, Kapandji score, grip strength, and thumb apposition/opposition pinch strength all improved significantly (P < .05). The mean QuickDASH score was 30 ± 16, and PRWE score was 32 ± 17. Patients who had unilateral partial thumb denervation demonstrated greater improvement in grip strength than patients who had bilateral partial thumb denervation procedures (P = .01). In this clinical case series, our method of basilar thumb joint partial denervation has been effective in improving clinical outcomes and reducing pain due to osteoarthritis. IV, case series.

Analgesic Effect of Addition of Pectointercostal Block to Serratus Anterior Plane Block in Breast Surgeries: A Randomized, Controlled Trial

BACKGROUND: Ultrasound-guided serratus anterior plane block (SAPB) is an efficient perioperative analgesic modality for breast surgeries. SAPB does not block the anterior cutaneous branches of the intercostal nerves; thus, it does not provide adequate analgesia for the parasternal region and the medial side of the breast. A new parasternal block, the pectointercostal fascial plane block (PIFB) has been developed to overcome this issue. OBJECTIVES: The study aimed to evaluate the perioperative analgesic effect of using PIFB in addition to SAPB. The primary outcome was to evaluate the postoperative pain score. The secondary outcomes were to assess perioperative opioid requirements, hemodynamic stability, and the satisfaction of the patient and surgeon. STUDY DESIGN: The current study was a prospective, double-blinded, randomized controlled study. The current study was registered at the Pan-African Clinical Trials Registry (PACTR202001789968542) and was designed after obtaining ethical institutional approval (Institutional Review Board No 00012098, Federalwide Assurance No 00018699). SETTING: The study involved 60 women between 21 and 69 years old with breast cancer who were scheduled for modified radical mastectomy or conservative breast surgeries in a university hospital. METHODS: After verbal and informed written consent, the patients were allocated to Group 1, which received SAPB, and Group 2, which received SAPB with PIFB. We assessed the Visual Analog Scale (VAS), perioperative opioid requirements, intraoperative hemodynamic stability, rescue analgesia, and complications. Patient and surgeon satisfaction were surveyed using a questionnaire where one is very dissatisfied and 5 is very satisfied. RESULTS: Intraoperative mean arterial blood pressure (MABP) and heart rate were significantly lower in Group 2 (SAPB+PIFB). The number of patients who needed intraoperative fentanyl was also significantly lower in Group 2 (SAPB+PIFB) (P value = 0.010). Postoperative VAS showed no significant difference in both groups. The number of patients who needed postoperative rescue morphine, time for the first rescue analgesia, first morphine dose (mg), and total opioid consumption were also comparable for both groups. Patient satisfaction and surgeon satisfaction were comparable for both groups (P values = 1.000 and 0.496, respectively). LIMITATIONS: VAS was not recorded during movements and no follow-up was done to detect the potential effect on chronic postmastectomy pain. Moreover, after reviewing the literature, there was no efficient data about adding PIFB with different regional blocks for breast surgery. CONCLUSIONS: The number of patients who needed intraoperative fentanyl, as well as the MABP and heart rate were significantly lower in Group 2 (SAPB+PIFB). Postoperative vital signs, VAS, postoperative analgesic requirements, and opioid consumption were comparable for both groups. Patient satisfaction was comparable for both groups, while surgeon satisfaction was higher in Group 2 (SAPB+PIFB) but statistically not significant. KEY WORDS: Pectointercostal, fascial plane block, serratus anterior plane block, breast surgery, regional analgesia for mastectomy

Dextran Amine-Conjugated Neural Tracing in Mosquitoes.

To understand the circuitry of the brain, it is often advantageous to visualize the processes of a single neuron or population of neurons. Identifying sites where a neuron, or neurons, originates and where it projects can allow a researcher to begin to map the circuitry underlying various processes, including sensory-guided behaviors. Furthermore, neural tracing allows one to map locations where processes terminate onto regions of the brain that may have known functions and sometimes to identify candidate upstream or downstream connections, based on proximity. Many methods of neural tracing are available; here, we focus on loading fluorescent dyes into a neuron (fluorescent dye filling). Different options for dyes exist to label neurites. Among the most versatile and easy to use are dextran amine-conjugated dyes. They fill neurons bidirectionally, not discriminating between anterograde or retrograde loading direction. Dye filling must be done in unfixed tissue, as the dye needs to move through the neurons; however, dextran amine conjugates are aldehyde-fixable and once cells have been fully loaded with dye the tissue can be fixed and subjected to immunostaining. Coupling neural tracing with immunofluorescence is a useful way to determine specific brain or ventral nerve cord (VNC) regions where a neuron projects. This protocol describes methods for loading dextran amine conjugated dyes into a sensory tissue in the mosquito to visualize sites of sensory neuron innervation in the central nervous system, as well as efferent projections to these structures. This protocol is described for Aedes aegypti, for which it was optimized, but it also works across a variety of insects.

Ultrasonography Guided Modified BRILMA (Blocking the Cutaneous Branches of Intercostal Nerves in the Middle Axillary Line) Block in Bariatric Surgery.

Background: Postoperative pain is one of the major problems after laparoscopic sleeve gastrectomy besides complications. Management of pain control is still unclear in the obese population. Modified BRILMA (blocking the cutaneous branches of intercostal nerves in the middle axillary line) is a new analgesia technique which is performed by ultrasonography guided through the way between eighth and ninth rib level. This study is to evaluate the efficiency of modified BRILMA in bariatric patients while comparing with trocar site infiltration. Materials and Methods: This is a prospective designed retrospective data analysis study. Patients undergoing laparoscopic sleeve gastrectomy between June 2019 and January 2020 were divided into two groups. One group underwent BRILMA block; the other group used traditional trocar site injection. Postoperative pain was followed by using visual analogue scale (VAS) (at 1, 3, 6, 12, 24, 36, 48 hours postoperatively). Results: Thirty patients were included in the study. Twenty-four (80%) of the patients were women, and 6 (20%) of the patients were men. Mean body mass index of patients were 39.83 ± 4.02 kg/m2. Mean operational time was calculated 86.16 ± 19.94 minutes. When the patients' VAS was compared, 12th hour VAS value was statistically less in the BRILMA group. There were no significant differences in other hours' VAS between two groups. When compared with the use of opioid amount, there were no statistically significant difference between the two groups (P = .66), but BRILMA group had less amount. Conclusion: Modified BRILMA is an alternative technique to the use of trocar site bupivacain injection in bariatric surgery. It is new technique that is tried in bariatric population, which is also cost-effective and has less opioid consumption.

Corneal neuroepithelial compartmentalized microfluidic chip model for evaluation of toxicity-induced dry eye

Part of the lacrimal functional unit, the cornea protects the ocular surface from numerous environmental aggressions and xenobiotics. Toxicological evaluation of compounds remains a challenge due to complex interactions between corneal nerve endings and epithelial cells. To this day, models do not integrate the physiological specificity of corneal nerve endings and are insufficient for the detection of low toxic effects essential to anticipate Toxicity-Induced Dry Eye (TIDE).Using high-content imaging tool, we here characterize toxicity-induced cellular alterations using primary cultures of mouse trigeminal sensory neurons and corneal epithelial cells in a compartmentalized microfluidic chip.We validate this model through the analysis of benzalkonium chloride (BAC) toxicity, a well-known preservative in eyedrops, after a single (6h) or repeated (twice a day for 15 min over 5 days) topical 5.10−4% BAC applications on the corneal epithelial cells and nerve terminals.In combination with high-content image analysis, this advanced microfluidic protocol reveal specific and tiny changes in the epithelial cells and axonal network as well as in trigeminal cells, not directly exposed to BAC, with ATF3/6 stress markers and phospho-p44/42 cell activation marker. Altogether, this corneal neuroepithelial chip enables the evaluation of toxic effects of ocular xenobiotics, distinguishing the impact on corneal sensory innervation and epithelial cells. The combination of compartmentalized co-culture/high-content imaging/multiparameter analysis opens the way for the systematic analysis of toxicants but also neuroprotective compounds.

Superior Cluneal Nerve Entrapment Syndrome: Thought to Be Spondylolysis.

A rare but typically overlooked diagnosis in the orthopaedic surgery community is superior cluneal nerve (SCN) entrapment syndrome. The cluneal nerves function as purely sensory fibers, and the SCNs provide cutaneous innervation to the posterior parasacral, gluteal, and posterolateral thigh regions. When irritated, this syndrome can cause acute and chronic lower back pain and lower extremity symptoms. A 14-year-old adolescent girl presented to the clinic for an evaluation of pain in the right side of her lower back. The patient's physical examination showed tenderness to palpation on the right posterior iliac crest seven centimeters from the midline. Her neurologic examination demonstrated normal deep tendon reflexes, muscle strength, and sensation in the L2-S1 dermatomal distribution. Although imaging showed evidence of a left L5 spondylolysis, she responded positively to a steroid injection over the posterior iliac crest but negatively to one over the L5 pars defect. She later underwent a right SCN decompression surgery. After the procedure, she reported at least 90% improvement in her pain and rated it as a one in severity, on a scale of 0 to 10. Research regarding SCN entrapment syndrome has increased in the past several years. However, most of these studies are limited to the adult population. Therefore, more reports highlighting the potential for this syndrome in adolescents are needed as well.

The nervous system and adipose tissues: a tale of dialogues.

White, beige and brown adipose tissues play a crucial role in maintaining energy homeostasis. Due to the heterogeneous and diffuse nature of fat pads, this balance requires a fine and coordinated control of many actors and therefore permanent dialogues between these tissues and the central nervous system. For about two decades many studies have been devoted to describe the neuro-anatomical and functional complexity involved to ensure this dialogue. Thus, if it is now clearly demonstrated that there is an efferent sympathetic innervation of different fat depots controlling plasticity as well as metabolic functions of the fat pad, the crucial role of sensory innervation capable of detecting local signals informing the central nervous system of the metabolic state of the relevant pads is much more recent. The purpose of this review is to provide the current state of knowledge on this subject.

The medial plantar artery: anatomy and implications in local flaps of the foot

The medial plantar artery (MPA), as a terminal branch of the posterior tibial artery, provides perfusion to the musculature of the medial compartment of the plantar foot as well as cutaneous branches to the skin. The artery and its perforators serve as the foundation for several flaps based on various soft tissue components for the coverage of small defects of the foot. Most noteworthy is the fasciocutaneous flap, which utilizes the skin and the unique properties of the plantar foot. Understanding the anatomical relationship of the terminal branches of the MPA, the superficial and deep branches, is necessary in determining the type of tissue and the flap design to be utilized for reconstruction.

Proprioceptive innervation of the human lips.

The objective of this study was to analyze the proprioceptive innervation of human lips, especially of the orbicularis oris muscle, since it is classically accepted that facial muscles lack typical proprioceptors, that is, muscle spindles, but recently this has been doubted. Upper and lower human lips (n = 5) from non-embalmed frozen cadavers were immunostained for detection of S100 protein (to identify nerves and sensory nerve formations), myosin heavy chain (to label muscle fibers within muscle spindles), and the mechano-gated ion channel PIEZO2. No muscle spindles were found, but there was a high density of sensory nerve formations, which were morphologically heterogeneous, and in some cases resemble Ruffini-like and Pacinian sensory corpuscles. The axons of these sensory formations displayed immunoreactivity for PIEZO2. Human lip muscles lack typical proprioceptors but possess a dense sensory innervation which can serve the lip proprioception.

Morphology and morphometry of the ulnar nerve in the forelimb of pigs.

The knowledge of the morphology and morphometry of peripheral nerves is essential for developing neural interfaces and understanding nerve regeneration in basic and applied research. Currently, the most adopted animal model is the rat, even though recent studies have suggested that the neuroanatomy of large animal models is more comparable to humans. The present knowledge of the morphological structure of large animal models is limited; therefore, the present study aims to describe the morphological characteristics of the Ulnar Nerve (UN) in pigs. UN cross-sections were taken from seven Danish landrace pigs at three distinct locations: distal UN, proximal UN and at the dorsal cutaneous branch of the UN (DCBUN). The nerve diameter, fascicle diameter and number, number of fibres and fibre size were quantified. The UN diameter was larger in the proximal section compared to the distal segment and the DCBUN. The proximal branch also had a more significant number of fascicles (median: 15) than the distal (median: 10) and the DCBUN (median: 11) segments. Additionally, the mean fascicle diameter was smaller at the DCBUN (mean: 165 μm) than at the distal (mean: 197 μm) and proximal (mean: 199 μm) segments of the UN. Detailed knowledge of the microscopical structure of the UN in pigs is critical for further studies investigating neural interface designs and computational models of the peripheral nervous system.

Anatomical landmarks for ankle block

We aimed to describe anatomical landmarks to accurately locate the five nerves that are infiltrated to accomplish anaesthesia of the foot in an ankle block. Twenty-four formaldehyde-fixed cadaveric ankles were studied. Photographs of cross sections of the frozen legs, cut at a horizontal plane across the most prominent points of the medial and lateral malleoli, were analysed. The curvilinear distance from the most prominent point of the closest malleolus to each of the five cutaneous nerves and their depth from the skin surface were measured. Sural, tibial, deep peroneal, saphenous and medial dorsal cutaneous nerves were located 5.2 ± 1.3, 9.2 ± 2.4, 7.4 ± 1.9, 2.8 ± 1.1, 2.1 ± 0.6 mm deep to the skin surface. The curvilinear distances from the medial malleolus to the tibial, deep peroneal and saphenous nerves were 32.5 ± 8.9, 62.8 ± 11.1 and 24.4 ± 7.9 mm, respectively. The curvilinear distances from the lateral malleolus to the sural and medial dorsal cutaneous branches of superficial peroneal nerves were 27.9 ± 6.3 and 52.7 ± 7.3 mm, respectively. The deep peroneal nerve was found between the tendons of the extensor hallucis longus and the extensor digitorum longus in the majority of specimens, while the medial dorsal cutaneous nerve was almost exclusively found on the extensor digitorum longus tendon. The sural and tibial nerves were located around halfway between the most prominent point of the relevant malleolus and the posterior border of the Achilles tendon. In conclusion, this study describes easily identifiable, palpable bony and soft tissue landmarks that could be used to locate the nerves around the ankle.

Reverse Homodigital Artery Island Flap With Palmar Cutaneous Branches of the Proper Digital Nerve for Repairing of Finger Pulp Defect and Sensory Reconstruction: Is It Deserving?

Reverse Homodigital Artery Island Flap With Palmar Cutaneous Branches of the Proper Digital Nerve for Repairing of Finger Pulp Defect and Sensory Reconstruction: Is It Deserving?

Occipital artery: Anatomical variations and neurosurgical applications.

The occipital artery (OA) is a branch of the external carotid artery. It gives rise to several cutaneous, muscular, and meningeal branches to supply different anatomical areas. The implication of OA in the neurosurgical field is well-established in the literature. Our aim in this study is to draw a complete picture of the anatomical variations and neurosurgical applications of the OA. A literature review was conducted in Google Scholar and PubMed to review the studies discussing OA, its anatomical variation, and neurosurgical applications. We identified 29 articles that discuss the anatomical variations and neurosurgical applications of the OA. Certain variables are used to describe the surgical anatomy of OA. We also discussed certain applications of OA and its importance in neurosurgical bypass, embolization, and aneurysms. Comprehending the anatomy of the OA is crucial for neurosurgeons to safely and effectively perform procedures such as bypass and embolization. In addition, knowledge of the anatomical variations of the OA can help surgeons anticipate potential challenges and tailor their approach accordingly.

The Role of Sensory Innervation in Homeostatic and Injury-Induced Corneal Epithelial Renewal.

The cornea is the window through which we see the world. Corneal clarity is required for vision, and blindness occurs when the cornea becomes opaque. The cornea is covered by unique transparent epithelial cells that serve as an outermost cellular barrier bordering between the cornea and the external environment. Corneal sensory nerves protect the cornea from injury by triggering tearing and blink reflexes, and are also thought to regulate corneal epithelial renewal via unknown mechanism(s). When protective corneal sensory innervation is absent due to infection, trauma, intracranial tumors, surgery, or congenital causes, permanent blindness results from repetitive epithelial microtraumas and failure to heal. The condition is termed neurotrophic keratopathy (NK), with an incidence of 5:10,000 people worldwide. In this report, we review the currently available therapeutic solutions for NK and discuss the progress in our understanding of how the sensory nerves induce corneal epithelial renewal.

Comparative anatomy of the felid brachial plexus reflects differing hunting strategies between Pantherinae (snow leopard, Panthera uncia) and Felinae (domestic cat, Felis catus).

The brachial plexus, a network of ventral rami providing somatic sensory and motor innervation to the forelimb, is of particular importance in felids. Large-bodied pantherines require powerful rotatory and joint stabilizing forelimb muscles to maintain secure holds on large prey, while smaller-bodied felines are small prey specialists reliant on manual dexterity. Brachial plexus dissections of two snow leopards (Panthera uncia) and two domestic cats (Felis catus) revealed that generally the morphology of the brachial plexus is quite conserved. However, differences in the nerves supplying the shoulder and antebrachium may reflect differing prey capture strategies between the subfamilies. The brachial plexus of both species derives from ventral rami of C6-T1. In P. uncia, an extensive musculus (m.) subscapularis with multiple pennations is innervated by a larger number of nn. subscapulares, deriving from more spinal cord levels than in F. catus. C6 continues to become n. suprascapularis in both taxa; however, in F. catus, it also gives branches that join with C7, while in P. uncia, it is dedicated to musculi (mm.) supraspinatus, infraspinatus, and a small branch to cervical musculature. In F. catus, nervus (n.) medianus receives direct contributions from more ventral rami than P. uncia, possibly reflecting a greater reliance on manual dexterity in prey capture in the former. In addition to primary innervation by n. thoracodorsalis, m. latissimus dorsi is also innervated by n. thoracicus lateralis near the axilla in both taxa, suggesting that it may belong to a complex of proximal forelimb musculature along with mm. pectoralis profundus and cutaneus trunci.

Une étude anatomique clinique de la zone de sécurité pour l’abord palmaire pour l’arthroscopie du poignet

ObjectiveThe current study was to perform an anatomical observation of the volar approach for wrist arthroscopy and to establish the safe zone for this approach. MethodsEight preserved specimens and 2 fresh specimens were used to simulate the medial-to-lateral operation and to mark the volar approach. Based on anatomical measurements of the volar approach, the closest distances from the half, 6R, 6U, VR, VR’ and VU approaches to the adjacent important structures were established. ResultsThe closest distance from the half approach to the superficial branch of the radial nerve was 2.4±1.5mm. The closest distances from the 6U and 6R approaches to the dorsal carpal branch of the ulnar nerve were 16.2±1.3mm and 9.0±2.4mm, respectively. The closest distances from the VR and VR’ approaches to the palmar cutaneous branch of the median nerve were 6.7±1.1mm and 2.8±0.9mm, respectively; the closest distances to the radial artery were 6.3±4.0mm and 10.0±3.4mm, respectively. Moreover, both of the two approaches passed through the base of the flexor carpi radialis tendon. The closest distance from the VU approach to the ulnar artery and flexor digitorum profundus tendon were 3.3±1.4mm and 0.3±2.5mm, respectively. ConclusionsIn conclusion, a safe zone could be located for the establishment of the volar approach for wrist arthroscopy. Level of evidenceIII; retrospective study with no control group.

AAV-mediated gene transfer to colon-innervating primary afferent neurons.

Investigation of neural circuits underlying visceral pain is hampered by the difficulty in achieving selective manipulations of individual circuit components. In this study, we adapted a dual AAV approach, used for projection-specific transgene expression in the CNS, to explore the potential for targeted delivery of transgenes to primary afferent neurons innervating visceral organs. Focusing on the extrinsic sensory innervation of the mouse colon, we first characterized the extent of dual transduction following intrathecal delivery of one AAV9 vector and intracolonic delivery of a second AAV9 vector. We found that if the two AAV9 vectors were delivered one week apart, dorsal root ganglion (DRG) neuron transduction by the second vector was greatly diminished. Following delivery of the two viruses on the same day, we observed colocalization of the transgenes in DRG neurons, indicating dual transduction. Next, we delivered intrathecally an AAV9 vector encoding the inhibitory chemogenetic actuator hM4D(Gi) in a Cre-recombinase dependent manner, and on the same day injected an AAV9 vector carrying Cre-recombinase in the colon. DRG expression of hM4D(Gi) was demonstrated at the mRNA and protein level. However, we were unable to demonstrate selective inhibition of visceral nociception following hM4D(Gi) activation. Taken together, these results establish a foundation for development of strategies for targeted transduction of primary afferent neurons for neuromodulation of peripheral neural circuits.

The miR-183/96/182 cluster is a checkpoint for resident immune cells and shapes the cellular landscape of the cornea

PurposeThe conserved miR-183/96/182 cluster (miR-183C) regulates both corneal sensory innervation and corneal resident immune cells (CRICs). This study is to uncover its role in CRICs and in shaping the corneal cellular landscape at a single-cell (sc) level. MethodsCorneas of naïve, young adult [2 and 6 months old (mo)], female miR-183C knockout (KO) mice and wild-type (WT) littermates were harvested and dissociated into single cells. Dead cells were removed using a Dead Cell Removal kit. CD45+ CRICs were enriched by Magnetic Activated Cell Sorting (MACS). scRNA libraries were constructed and sequenced followed by comprehensive bioinformatic analyses. ResultsThe composition of major cell types of the cornea stays relatively stable in WT mice from 2 to 6 mo, however the compositions of subtypes of corneal cells shift with age. Inactivation of miR-183C disrupts the stability of the major cell-type composition and age-related transcriptomic shifts of subtypes of corneal cells. The diversity of CRICs is enhanced with age. Naïve mouse cornea contains previously-unrecognized resident fibrocytes and neutrophils. Resident macrophages (ResMφ) adopt cornea-specific function by expressing abundant extracellular matrix (ECM) and ECM organization-related genes. Naïve cornea is endowed with partially-differentiated proliferative ResMφ and contains microglia-like Mφ. Resident lymphocytes, including innate lymphoid cells (ILCs), NKT and γδT cells, are the major source of innate IL-17a. miR-183C limits the diversity and polarity of ResMφ. ConclusionmiR-183C serves as a checkpoint for CRICs and imposes a global regulation of the cellular landscape of the cornea.