MODL-16. SOMATICALLY ENGINEERED MOUSE MODELS RECAPITULATING CELLULAR AND MOLECULAR FEATURES OF HUMAN GBM

INTRODUCTION

Mouse models are instrumental in advancing our understanding of glioblastoma (GBM), however many commonly used models have features that limit their practicality or applicability. These limitations can include an incomplete immune context, a requirement for complex breeding strategies, high cost of specialized lines, and unpredictability in where tumors arise. We sought to develop and validate a mouse modeling system for some of the major human GBM subtypes that overcame these practical challenges.

METHODS

In vivo electroporation was used to introduce genetic alterations into periventricular cells of early postnatal C57Bl6/j mice. PiggyBac transposon/transposase and CRISPR-Cas9 systems were used to overexpress (OE) or knock out (KO) genes associated with mesenchymal (Nf1-KO/Pten-KO/p53-KO), classical (EGFRvIII-OE/Cdkn2a-KO/Pten-KO), and proneural (Pdgfra-OE/Cdk4-OE/p53-KO) IDH-WT GBM subtypes. KO or OE was confirmed by Indel Detection by Amplicon Analysis and immunofluorescent staining (IF). Tumours were analyzed for histologic, immunohistochemical, and transcriptional (RNAseq) features.

RESULTS

Tumors arose with near complete penetrance and median survivals of 36 to 116 days amongst models. All tumors were GFAP-expressing high-grade gliomas, with distinct phenotypes associated with different genetic combinations. Nf1-KO/Pten-KO/p53-KO tumors were composed of spindle cells. EGFRvIII-OE/Cdkn2a-KO/Pten-KO and Pdgfra-OE/Cdk4-OE/p53-KO tumors showed prevalence of small, round cells. Molecularly, Nf1-KO/Pten-KO/p53-KO tumors were enriched for human mesenchymal signature and displayed more differentiated phenotype. The Nf1-KO/Pten-KO/p53-KO model also showed increased stromal cells and macrophages. The other models had mixed proneural and classical profiles and were enriched for OPC- and NPC-like gene signatures found in human GBM. Once tumors formed, cells from each model were transplantable into C57Bl6/j mice to generate subsequent tumors.

CONCLUSION

We developed and validated a rapid, versatile, and reproducible system to model GBMs. These models allow for controlled study of GBM pathogenesis, progression, and treatment response, and allow for robust generation of syngeneic implantable mouse models that can serve as valuable tools for preclinical testing.

The neuronal tyrosine kinase receptor ligand ALKAL2 mediates persistent pain

The anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase known for its oncogenic potential that is involved in the development of the peripheral and central nervous system. ALK receptor ligands ALKAL1 and ALKAL2 were recently found to promote neuronal differentiation and survival. Here, we show that inflammation or injury enhanced ALKAL2 expression in a subset of TRPV1⁺ sensory neurons. Notably, ALKAL2 was particularly enriched in both mouse and human peptidergic nociceptors, yet weakly expressed in nonpeptidergic, large-diameter myelinated neurons or in the brain. Using a coculture expression system, we found that nociceptors exposed to ALKAL2 exhibited heightened excitability and neurite outgrowth. Intraplantar CFA or intrathecal infusion of recombinant ALKAL2 led to ALK phosphorylation in the lumbar dorsal horn of the spinal cord. Finally, depletion of ALKAL2 in dorsal root ganglia or blocking ALK with clinically available compounds crizotinib or lorlatinib reversed thermal hyperalgesia and mechanical allodynia induced by inflammation or nerve injury, respectively. Overall, our work uncovers the ALKAL2/ALK signaling axis as a central regulator of nociceptor-induced sensitization. We propose that clinically approved ALK inhibitors used for non–small cell lung cancer and neuroblastomas could be repurposed to treat persistent pain conditions.

This study aimed to explore women’s experiences of infant feeding in Ireland

Background

While breastfeeding may be among the most effective ways to ensure child health and survival, breastfeeding rates in Ireland are consistently low. This study aimed to explore women's experiences of infant feeding in Ireland.

Methods

Thematic analysis of feeding-related free-text comments from the National Maternity Experience Survey 2020 was undertaken. The survey collected data on the experiences of women who were 16 years or older and gave birth in one of Ireland's 19 maternity hospitals or units or had a home birth.

Results

3,204 women participated in the survey (50% response rate). In the first few days after birth, 41.9% of women breastfed exclusively, 29.0% used formula and breast milk, and 29.1% bottle fed only. 824 comments related to feeding were received. A number of themes were identified, including support and encouragement from healthcare professionals, information and education regarding feeding, and pressure and respect for personal preferences. Women highlighted that while breastfeeding was encouraged in antenatal care, this was not always the case in the postnatal ward, where formula was readily available, with an apparent lack of resources for breastfeeding women. Some women described feeling pressured to use a feeding method that was not their first preference, with some feeling pushed to breastfeed when this may not have been their wish, while women who wished to breastfeed felt pressured to supplement with formula. Staffing shortages on postnatal wards, a lack of lactation consultants and contradictory advice from healthcare professionals exacerbated difficulties with both feeding methods.

Conclusions

Some women experience a lack of practical support with infant feeding, regardless of feeding method, and clear and concise information on feeding practices is needed. The addition of lactation consultants, home supports and further education and training could benefit mothers on their breastfeeding journey.

Key messages

Barriers to breastfeeding included a lack of support from healthcare professionals and conflicting information. It is important to support women regardless of their chosen feeding method.

401 Three Birds with One Stone: Ureteric Calculus Precipitates Diagnosis and Resection of Three Primary Neoplasms

A 67 year-old female presented to our centre with a 2 day history of right flank pain, clinically suggestive of ureteric colic. Computed tomography (CT) confirmed a 6mm right ureteric calculus. However, CT also revealed a large 13cm ipsilateral renal mass, concerning for renal cell carcinoma (RCC). At ureteroscopy for management of the obstructing calculus, a small papillary lesion was noted in the bladder, and excised. Histology confirmed pTa low-grade transitional cell carcinoma.

Following discussion at the Urology multidisciplinary tumour board, MRI venogram (MRV) was recommended to delineate the extension of tumour into the renal vein, and to characterise a pelvic mass seen on original CT. MRV showed enhancing material extending into the IVC, consistent with tumour thrombus. However, it also identified a concerning 6cm solid ovarian mass.

The patient proceeded to open right radical nephrectomy and IVC thrombectomy, hysterectomy, bilateral salpingo-oopherectomy, and omental biopsy, with combined input from Urological, Gynaecological and Vascular surgical teams. Post-operative course was uneventful. Histology showed an 11cm pT3a G2 clear cell RCC, and 7.5cm ovarian fibroma, both fully excised. This case demonstrated the serendipity of a simple ureteric calculus precipitating a cascade of investigations, that ultimately led to complete resection of three primary neoplasms.

TRPV1 Activation Promotes β-arrestin2 Interaction with the Ribosomal Biogenesis Machinery in the Nucleolus:Implications for p53 Regulation and Neurite Outgrowth

Transient receptor potential vanilloids (TRPV1) are non-selective cation channels that sense and transduce inflammatory pain signals. We previously reported that activation of TRPV1 induced the translocation of β-arrestin2 (ARRB2) from the cytoplasm to the nucleus, raising questions about the functional role of ARRB2 in the nucleus. Here, we determined the ARRB2 nuclear signalosome by conducting a quantitative proteomic analysis of the nucleus-sequestered L395Q ARRB2 mutant, compared to the cytosolic wild-type ARRB2 (WT ARRB2), in a heterologous expression system. We identified clusters of proteins that localize to the nucleolus and are involved in ribosomal biogenesis. Accordingly, L395Q ARRB2 or WT ARRB2 after capsaicin treatment were found to co-localize and interact with the nucleolar marker nucleophosmin (NPM1), treacle protein (TCOF1) and RNA polymerase I (POL I). We further investigated the role of nuclear ARRB2 signaling in regulating neuroplasticity. Using neuroblastoma (neuro2a) cells and dorsal root ganglia (DRG) neurons, we found that L395Q ARRB2 mutant increased POL I activity, inhibited the tumor suppressorp53 (p53) level and caused a decrease in the outgrowth of neurites. Together, our results suggest that the activation of TRPV1 promotes the ARRB2-mediated regulation of ribosomal biogenesis in the nucleolus. The ARRB2-TCOF1-p53 checkpoint signaling pathway might be involved in regulating neurite outgrowth associated with pathological pain conditions.

Chronic morphine regulates TRPM8 channels via MOR-PKCβ signaling

Postoperative shivering and cold hypersensitivity are major side effects of acute and chronic opioid treatments respectively. TRPM8 is a cold and menthol-sensitive channel found in a subset of dorsal root ganglion (DRG) nociceptors. Deletion or inhibition of the TRPM8 channel was found to prevent the cold hyperalgesia induced by chronic administration of morphine. Here, we examined the mechanisms by which morphine was able to promote cold hypersensitivity in DRG neurons and transfected HEK cells. Mice daily injected with morphine for 5 days developed cold hyperalgesia. Treatment with morphine did not alter the expressions of cold sensitive TREK-1, TRAAK and TRPM8 in DRGs. However, TRPM8-expressing DRG neurons isolated from morphine-treated mice exhibited hyperexcitability. Sustained morphine treatment in vitro sensitized TRPM8 responsiveness to cold or menthol and reduced activation-evoked desensitization of the channel. Blocking phospholipase C (PLC) as well as protein kinase C beta (PKCβ), but not protein kinase A (PKA) or Rho-associated protein kinase (ROCK), restored channel desensitization. Identification of two PKC phosphorylation consensus sites, S1040 and S1041, in the TRPM8 and their site-directed mutation were able to prevent the MOR-induced reduction in TRPM8 desensitization. Our results show that activation of MOR by morphine 1) promotes hyperexcitability of TRPM8-expressing neurons and 2) induces a PKCβ-mediated reduction of TRPM8 desensitization. This MOR-PKCβ dependent modulation of TRPM8 may underlie the onset of cold hyperalgesia caused by repeated administration of morphine. Our findings point to TRPM8 channel and PKCβ as important targets for opioid-induced cold hypersensitivity.

TRPV1 promotes opioid analgesia during inflammation

Pain and inflammation are inherently linked responses to injury, infection, or chronic diseases. Given that acute inflammation in humans or mice enhances the analgesic properties of opioids, there is much interest in determining the inflammatory transducers that prime opioid receptor signaling in primary afferent nociceptors. Here, we found that activation of the transient receptor potential vanilloid type 1 (TRPV1) channel stimulated a mitogen-activated protein kinase (MAPK) signaling pathway that was accompanied by the shuttling of the scaffold protein β-arrestin2 to the nucleus. The nuclear translocation of β-arrestin2 in turn prevented its recruitment to the μ-opioid receptor (MOR), the subsequent internalization of agonist-bound MOR, and the suppression of MOR activity that occurs upon receptor desensitization. Using the complete Freund's adjuvant (CFA) inflammatory pain model to examine the role of TRPV1 in regulating endogenous opioid analgesia in mice, we found that naloxone methiodide (Nal-M), a peripherally restricted, nonselective, and competitive opioid receptor antagonist, slowed the recovery from CFA-induced hypersensitivity in wild-type, but not TRPV1-deficient, mice. Furthermore, we showed that inflammation prolonged morphine-induced antinociception in a mouse model of opioid receptor desensitization, a process that depended on TRPV1. Together, our data reveal a TRPV1-mediated signaling pathway that serves as an endogenous pain-resolution mechanism by promoting the nuclear translocation of β-arrestin2 to minimize MOR desensitization. This previously uncharacterized mechanism may underlie the peripheral opioid control of inflammatory pain. Dysregulation of the TRPV1-β-arrestin2 axis may thus contribute to the transition from acute to chronic pain.

Primary Renal Carcinoid - A Case Report

Carcinoid tumours in the abdomen are uncommon, but typically occur in the gastrointestinal tract. Primary renal carcinoid is an extremely rare tumour, poorly described in the literature. We describe an unusual case where an atypical renal mass on imaging led to a preoperative diagnosis of renal carcinoid on imaging guiding biopsy.

Modulation of the immune response to Mycobacterium tuberculosis during malaria/M. tuberculosis co-infection

Tuberculosis (TB) causes significant morbidity and mortality on a global scale. The African region has 24% of the world's TB cases. TB overlaps with other infectious diseases such as malaria and HIV, which are also highly prevalent in the African region. TB is a leading cause of death among HIV-positive patients and co-infection with HIV and TB has been described as a syndemic. In view of the overlapping epidemiology of these diseases, it is important to understand the dynamics of the immune response to TB in the context of co-infection. We investigated the cytokine response to purified protein derivative (PPD) in peripheral blood mononuclear cells from TB patients co-infected with HIV or malaria and compared it to that of malaria- and HIV-free TB patients. A total of 231 subjects were recruited for this study and classified into six groups; untreated TB-positive, TB positive subjects on TB drugs, TB- and HIV-positive, TB- and malaria-positive, latent TB and apparently healthy control subjects. Our results demonstrate maintenance of interferon (IFN)-γ production in HIV and malaria co-infected TB patients in spite of lower CD4 counts in the HIV-infected cohort. Malaria co-infection caused an increase in the production of the T helper type 2 (Th2)-associated cytokine interleukin (IL)-4 and the anti-inflammatory cytokine IL-10 in PPD-stimulated cultures. These results suggest that malaria co-infection diverts immune response against M. tuberculosis towards a Th-2/anti-inflammatory response which might have important consequences for disease progression.

The stress protein heat shock cognate 70 (Hsc70) inhibits the Transient Receptor Potential Vanilloid type 1 (TRPV1) channel

Background

Specialized cellular defense mechanisms prevent damage from chemical, biological, and physical hazards. The heat shock proteins have been recognized as key chaperones that maintain cell survival against a variety of exogenous and endogenous stress signals including noxious temperature. However, the role of heat shock proteins in nociception remains poorly understood. We carried out an expression analysis of the constitutively expressed 70 kDa heat-shock cognate protein, a member of the stress-induced HSP70 family in lumbar dorsal root ganglia from a mouse model of Complete Freund’s Adjuvant-induced chronic inflammatory pain. We used immunolabeling of dorsal root ganglion neurons, behavioral analysis and patch clamp electrophysiology in both dorsal root ganglion neurons and HEK cells transfected with Hsc70 and Transient Receptor Potential Channels to examine their functional interaction in heat shock stress condition.

Results

We report an increase in protein levels of Hsc70 in mouse dorsal root ganglia, 3 days post Complete Freund’s Adjuvant injection in the hind paw. Immunostaining of Hsc70 was observed in most of the dorsal root ganglion neurons, including the small size nociceptors immunoreactive to the TRPV1 channel. Standard whole-cell patch-clamp technique was used to record Transient Receptor Potential Vanilloid type 1 current after exposure to heat shock. We found that capsaicin-evoked currents are inhibited by heat shock in dorsal root ganglion neurons and transfected HEK cells expressing Hsc70 and TRPV1. Blocking Hsc70 with matrine or spergualin compounds prevented heat shock-induced inhibition of the channel. We also found that, in contrast to TRPV1, both the cold sensor channels TRPA1 and TRPM8 were unresponsive to heat shock stress. Finally, we show that inhibition of TRPV1 depends on the ATPase activity of Hsc70 and involves the rho-associated protein kinase.

Conclusions

Our work identified Hsc70 and its ATPase activity as a central cofactor of TRPV1 channel function and points to the role of this stress protein in pain associated with neurodegenerative and/or metabolic disorders, including aging.

Evaluating the cost of iatrogenic urethral catheterisation injuries

INTRODUCTION

Technique is vital to prevent urethral trauma during urethral catheterisation (UC). Education programmes are helpful but are not compulsory and safe UC remains operator dependent. Traumatic UC is associated with increased morbidity, length of stay, resource utilisation and surgical intervention.

AIM

To determine the cost of iatrogenic urethral injuries managed in a tertiary referral centre over a 6-month period.

METHODS

A 6-month prospective study monitored iatrogenic urethral injuries secondary to traumatic UC. Included were referrals from district hospitals and inpatient consultations relating to urethral injury caused by traumatic UC. The added cost of management was estimated.

RESULTS

Thirteen iatrogenic urethral injuries were recorded in 6 months. Management included open surgery for a ruptured bladder (n = 1), flexible cystourethroscopy (n = 10), suprapubic catherisation (n = 4), 3-way catheterisation (n = 4) and catheter re-insertion under direct vision (n = 6). The cost of acute management of these injuries was approximately €50,000 including theatre costs, ambulance transfer, hospital stay, procedural and equipment costs and short-term follow-up care.

CONCLUSION

Iatrogenic injuries during UC represent a significant cost burden to the healthcare system. Training programmes should be compulsory for all healthcare professionals routinely involved in catheterisation procedures.

Ruxolitinib in corticosteroid-refractory graft-versus-host disease after allogeneic stem cell transplantation: a multicenter survey

Despite major improvements in allogeneic hematopoietic cell transplantation over the past decades, corticosteroid-refractory (SR) acute (a) and chronic (c) graft-versus-host disease (GVHD) cause high mortality. Preclinical evidence indicates the potent anti-inflammatory properties of the JAK1/2 inhibitor ruxolitinib. In this retrospective survey, 19 stem cell transplant centers in Europe and the United States reported outcome data from 95 patients who had received ruxolitinib as salvage therapy for SR-GVHD. Patients were classified as having SR-aGVHD (n=54, all grades III or IV) or SR-cGVHD (n=41, all moderate or severe). The median number of previous GVHD-therapies was 3 for both SR-aGVHD (1-7) and SR-cGVHD (1-10). The overall response rate was 81.5% (44/54) in SR-aGVHD including 25 complete responses (46.3%), while for SR-cGVHD the ORR was 85.4% (35/41). Of those patients responding to ruxolitinib, the rate of GVHD-relapse was 6.8% (3/44) and 5.7% (2/35) for SR-aGVHD and SR-cGVHD, respectively. The 6-month-survival was 79% (67.3-90.7%, 95% confidence interval (CI)) and 97.4% (92.3-100%, 95% CI) for SR-aGVHD and SR-cGVHD, respectively. Cytopenia and cytomegalovirus-reactivation were observed during ruxolitinib treatment in both SR-aGVHD (30/54, 55.6% and 18/54, 33.3%) and SR-cGVHD (7/41, 17.1% and 6/41, 14.6%) patients. Ruxolitinib may constitute a promising new treatment option for SR-aGVHD and SR-cGVHD that should be validated in a prospective trial.

TRPV1 sensitization mediates postinflammatory visceral pain following acute colitis

Quiescent phases of inflammatory bowel disease (IBD) are often accompanied by chronic abdominal pain. Although the transient receptor potential vanilloid 1 (TRPV1) ion channel has been postulated as an important mediator of visceral hypersensitivity, its functional role in postinflammatory pain remains elusive. This study aimed at establishing the role of TRPV1 in the peripheral sensitization underlying chronic visceral pain in the context of colitis. Wild-type and TRPV1-deficient mice were separated into three groups (control, acute colitis, and recovery), and experimental colitis was induced by oral administration of dextran sulfate sodium (DSS). Recovery mice showed increased chemically and mechanically evoked visceral hypersensitivity 5 wk post-DSS discontinuation, at which point inflammation had completely resolved. Significant changes in nonevoked pain-related behaviors could also be observed in these animals, indicative of persistent discomfort. These behavioral changes correlated with elevated colonic levels of substance P (SP) and TRPV1 in recovery mice, thus leading to the hypothesis that SP could sensitize TRPV1 function. In vitro experiments revealed that prolonged exposure to SP could indeed sensitize capsaicin-evoked currents in both cultured neurons and TRPV1-transfected human embryonic kidney (HEK) cells, a mechanism that involved TRPV1 ubiquitination and subsequent accumulation at the plasma membrane. Importantly, although TRPV1-deficient animals experienced similar disease severity and pain as wild-type mice in the acute phase of colitis, TRPV1 deletion prevented the development of postinflammatory visceral hypersensitivity and pain-associated behaviors. Collectively, our results suggest that chronic exposure of colon-innervating primary afferents to SP could sensitize TRPV1 and thus participate in the establishment of persistent abdominal pain following acute inflammation.

Transurethral resection of the prostate--"now and then"

The number of transurethral resections of the prostate (TURP) performed each year is decreasing. The aim of this study was to assess a cohort of patients undergoing TURP and compare this to one twenty years earlier in terms of procedure, complications and outcomes. A retrospective comparative analysis of one hundred consecutive TURPs performed in 2010 was compared to one hundred cases performed in 1990. Fifty-five (55%) had a urinary catheter (UC) in situ pre-operatively in 2010 compared to 22 (22%) in 1990. The length of catheterisation time was significantly longer in 2010 compared with 1990 (average 65 days vs 20 days). Infective complications occurred in six (6%) patients in 2010 and three (3%) in the 1990 cohort. Patients who had UCs in situ preoperatively for longer periods had a higher rate of infective complications and more serious complications. This highlights the importance of early specialist referral for patients diaqnosed with urinary retention.

Strategies to inhibit alloantibody production in alloprimed murine recipients of hematopoietic stem cell grafts

Alloantibody, not primed T cells, is the major barrier to bone marrow (BM) engraftment in allosensitized mice. We have shown that a single intravenous injection of donor splenocytes, to mimic a blood transfusion, results in high, sustained levels of serum alloantibody sufficient to eliminate donor BM within 3 h, resulting in uniform mortality in lethally irradiated allogeneic recipients. Current studies focused preventing and treating allopriming. Blockade of B cell survival signals with mTACI-Ig pre- and postpriming was ineffective, as was the B cell but not plasma cell depleting anti-CD20 mAb. Germinal center formation inhibition by lymphotoxin-beta receptor-Ig (LβR-Ig) diminished allosensitization, although conditional Prmd1 (Blimp-1) deletion in CD19+ cells was highly effective. By combining anti-CD20 mAb to reduce B cells and LTβR-Ig to diminish the frequency of B cells that could form germinal centers pre- and postpriming, allosensitization was precluded, permitting long-term survival in T- and NK-depleted, irradiated allogeneic recipients, whereas combined therapy postpriming alone was ineffective. As evidence of the critical role of B cells, the proteosomal inhibitor, bortezomib, given unencapsulated or encapsulated, proved ineffective in influencing allosensitization. These data extend our understanding of allopriming and provide a potential therapy for patients at risk for allosensitization and BM graft rejection.

A patient reported outcome measure (PROM) assessing quality of care in the urology hospital outpatient setting

A prospective blind PROM (patient reported outcome measure) study performed in our urology department examined the outpatient-clinic experience. 104 questionnaires were completed. 23 patients (22%) felt the waiting times for appointments was excessive. 13 patients (13%) experienced difficulty in contacting administrative staff. 98 patients (94%) considered the waiting areas good but 31 patients (31%) considered lack of privacy an issue. Consultants saw 65 patients (63%). 62 patients (60%) expected to be seen by a consultant. 32 patients (31%) felt consultation with a different doctor on return visits was unsatisfactory. 76 patients (73%) "fully trusted" their doctors. 78 patients (75%) rated their visit excellent, 10 patients (10%) added comments. Despite frustration with waiting times, the experience of patients reflects a positive rapport and trust between patient and doctor.

Targeting the transient receptor potential vanilloid type 1 (TRPV1) assembly domain attenuates inflammation-induced hypersensitivity

The transient receptor potential channel vanilloid type 1 (TRPV1) is a non-selective cation channel expressed in sensory neurons of the dorsal root and trigeminal ganglia. TRPV1 is a polymodal channel activated by noxious heat, capsaicin, and protons. As a sensor for noxious stimuli, TRPV1 channel has been described as a key contributor to pain signaling. To form a functional channel, TRPV1 subunits must assemble into tetramers, and several studies have identified the TRPV1 C terminus as an essential element in subunit association. Here we combined biochemical assays with electrophysiology and imaging-based bimolecular fluorescence complementation (BiFC) and bioluminescence resonance energy transfer (BRET) in live cells to identify a short motif in the C-terminal tail of the TRPV1 subunit that governs channel assembly. Removing this region through early truncation or targeted deletion results in loss of subunit association and channel function. Importantly, we found that interfering with TRPV1 subunit association using a plasma membrane-tethered peptide attenuated mechanical and thermal hypersensitivity in two mouse models of inflammatory hyperalgesia. This represents a novel mechanism to disrupt TRPV1 subunit assembly and hence may offer a new analgesic tool for pain relief.

A macromolecular trafficking complex composed of β₂-adrenergic receptors, A-Kinase Anchoring Proteins and L-type calcium channels

Abstract Sympathetic modulation of cardiac L-type calcium channels is an important mechanism for regulating heart rate and cardiac contractility. At the molecular level, activation of β-adrenergic receptors (βAR) increases calcium influx into cardiac myocytes by activating protein kinase A (PKA), leading to subsequent phosphorylation of L-type calcium channels. In the case of the β2AR, this process is facilitated by the presence of A-Kinase Anchoring Proteins (AKAPs) that serve as scaffolding proteins for the L-type calcium channel and the β2AR complex. Our work has shown that, in addition to facilitating PKA phosphorylation of the channel, AKAPs also promote an increase in the Cav1.2 channel surface expression. Here we review the molecular mechanisms of β2AR/AKAP/L-type channel interactions and trafficking.