1 2 3 4 5 6 7 Excample of an output of transcriptional profiling study using Illumina  sequencing performed in our lab. Shown is just a tiny fragment of the complete  list, copmprising about 7K genes revealing differential expression in the studied  mutant.  8 9 10 11 Excample of an output of transcriptional profiling study using Illumina  sequencing performed in our lab. Shown is just a tiny fragment of the complete  list, copmprising about 7K genes revealing differential expression in the studied  mutant.  12 13 One of such recent and very useful tools is Gorilla software, freely available at  http://cbl‐gorilla.cs.technion.ac.il/. 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 According to experimental evidence for the system under study, the hormone IAA, the peptide TDIF, and the microRNA MIR165/6 are able to move among the cells. In the case of TDIF and MIR165/6, the mobility is defined as diffusion and is given by the following equation: g(t+1)T[i]= H(g(t)[i]+ D (g(t)[i+1]+g(t)[i‐1] – N(g(t)[i]))‐b) (2), where g(t)T[i] is the total amount of TDIF or MIR165 in cell (i). D is a parameter that determines the proportion of g that can move from any cell to neighboring ones and is correlated to the diffusion rate of g. b is a constant corresponding to a degradation term. H is a step function that converts the continuous values of g into a discrete variable that may attain values of 0, 1 or 2. N stands for the number of neighbors in each cell. Boundary conditions are zero‐flux. In the case of IAA, the mobility is defined as active transport dependent on the radial localization of the PIN efflux transporters and is defined by the equation: iaa(t+1)T[i]=Hiaa(iaa(t)[i]+Diaa(pin(t)[i+1])(iaa(t)[i+1])+Diaa(pin(t)[i‐1])(iaa(t)[i‐ 1])−N(Diaa)(pin(t)[i])(iaa(t)[i])−biaa) (3), where Diaa is a parameter that determines the proportion of IAA that can be transported among cells. The transport depends on the presence of IAA and PIN in the cells and biaa corresponds to a degradation term. As in equation 2, H is a step function that converts the continuous values to discrete ones and N stands for the number of neighbors in each cell. Boundary conditions for IAA motion are also zero‐flux. 29 The proposed model considers data that we identified and evaluated through an extensive search (up to January 2012). It takes into account molecular interactions, hormonal and expression patterns, and cell‐to‐cell communication processes that have been reported to affect vascular patterning in the bundles of Arabidopsis. The model components and interactions are graphically presented in the figure above. In the network model, nodes stand for molecular elements regulating one another’s activities. Most of the nodes can take only 1 or 0 values (light gray nodes in the figure), corresponding to “present” or “not present,” respectively. Since the formation of gradients of hormones and diffusible elements may have important consequences in pattern formation, mobile elements TDIF and MIR, as well as members of the CK and IAA signaling systems, can take 0, 1 or 2 values (dark gray nodes in the figure above) Benitez and Hejatko, submitted. 30 31 In comparison to the model shown on slide 21, the final version of the model  contains the predicted interactions (dashed lines). 32 33 34 The initial conditions specify the initial state of some of the network elements (figure above) and are the following : I) In the procambial position (central compartment), CK is initially available and there is an initial and sustained IAA input or self‐upregulation. This  condition is supported by several lines of evidence. Also HB8, a marker of early vascular development that has been found in preprocambial cells, is  assumed to be initially present at this position. These conditions are not fixed, however. After the initial configuration, all the members of the CK and  IAA signaling pathways, as well as HB8, can change their states according to the logical rules.  II) In the xylem and phloem positions, it is assumed that no element is initially active except for the CK signaling pathway and TDIF, both in the phloem  position.The level of expression for a given node is represented by a discrete variable g and its value at a time t+1 depends on the state of other  components of the network (g1, g2, ..., gN) at a previous time unit. The state of every gene g therefore changes according to:  gn(t+1)=Fn(gn1(t),gn2(t),..., gnk(t)) (1). In this equation, gn1, gn2,…, gnk are the regulators of gene gn and Fn is a discrete function known as a logical rule (logical rules are grounded in available experimental data, for example see slide 20). Given the logical rules, it is possible to follow the dynamics of the network for any given initial configuration of the nodes expression state. One of the most important traits of dynamic models is the existence of steady states in which the entire network enters into a selfsustained configuration of the nodes state. It is thought that in developmental systems such self‐sustained states correspond to particular cell types. According to experimental evidence for the system under study, the hormone IAA, the peptide TDIF, and the microRNA MIR165/6 are able to move among the cells. In the case of TDIF and MIR165/6, the mobility is defined as diffusion and is given by the following equation: g(t+1)T[i]= H(g(t)[i]+ D (g(t)[i+1]+g(t)[i‐1] – N(g(t)[i]))‐b) (2), where g(t)T[i] is the total amount of TDIF or MIR165 in cell (i). D is a parameter that determines the proportion of g that can move from any cell to neighboring ones and is correlated to the diffusion rate of g. b is a constant corresponding to a degradation term. H is a step function that converts the continuous values of g into a discrete variable that may attain values of 0, 1 or 2. N stands for the number of neighbors in each cell. Boundary conditions are zero‐flux. In the case of IAA, the mobility is defined as active transport dependent on the radial localization of the PIN efflux transporters and is defined by the equation: iaa(t+1)T[i]=Hiaa(iaa(t)[i]+Diaa(pin(t)[i+1])(iaa(t)[i+1])+Diaa(pin(t)[i‐1])(iaa(t)[i‐1])−N(Diaa)(pin(t)[i])(iaa(t)[i])−biaa) (3), where Diaa is a parameter that determines the proportion of IAA that can be transported among cells. The transport depends on the presence of IAA and PIN in the cells and biaa corresponds to a degradation term. As in equation 2, H is a step function that converts the continuous values to discrete ones and N stands for the number of neighbors in each cell. Boundary conditions for IAA motion are also zero‐flux. Using the logical rules, equations 1–3, and a broad range of parameter values (not shown here), it is possible fully to reproduce the results and  analyses reported in the following sections (see the figure above for the simulation time course). 35 Another representation of the distinct expression profiles in the individual  vascular bundle compartments (phloem, procambium and xylem). 36 37 38 39 40 Hypertrophic scars (HS) area fibroproliferative disorder of the skin, which causes aesthetic and  functional impairment. However, the molecular pathogenesis of this disease remains largely  unknown and currently no efficient treatment exists. MicroRNAs (miRNAs) are involved in a  variety of pathophysiological processes, however the role of miRNAs in HS development remains  unclear. To investigate the miRNA expression signature of HS, microarray analysis was performed  and 152 miRNAs were observed to be differentially expressed in HS tissue compared with normal  skin tissues. Of the miRNAs identified, miRNA‐21 (miR‐21) was significantly increased in HS  tissues and hypertrophic scar fibroblasts (HSFBs) as determined by reverse  transcription‐quantitative polymerase chain reaction analysis. It was also observed that, when  miR‐21 in HSFBs was blocked through use of an antagomir, the phenotype of fibrotic fibroblasts  in vitro was reversed, as demonstrated by growth inhibition, induction of apoptosis and  suppressed expression of fibrosis‐associated genes collagen type I α 1 chain (COL1A1), COL1A2  and fibronectin. Furthermore, miR‐21 antagomir administration significantly reduced the  severity of HS formation and decreased collagen deposition in a rabbit ear HS model. The total  scar area and scar elevation index were calculated and were demonstrated to be significantly  decreased in the treatment group compared with control rabbits. These results indicated that  the miR‐21 antagomir has a therapeutic effect on HS and suggests that targeting miRNAs may be  a successful and novel therapeutic strategy in the treatment of fibrotic diseases that are difficult  to treat with existing methods. miRNA expression signature profiling in hypertrophic scars (HS). (A) Volcano plot presenting  differentially expressed miRNAs between HS and paired (non‐scar, obtained from donor sites  during scar resection) NS tissue. miRNA microarray expression profiling from three paired HS and  NS tissues was performed. Differentially expressed miRNAs were identified by fold change and a  P‐value calculated using Student's t‐test. The threshold set to identify up and downregulated  genes was a fold change ≥2 and P<0.05. Red dots indicate points‐of‐interest that exhibit  large‐magnitude fold‐changes (x‐axis; log2 of the fold change) and high statistical significance  (y‐axis; ‐log10 of the P‐value). (B) Hierarchical clustering showing differentially expressed miRNAs  from HS samples compared with paired NS tissues. Each row represents one miRNA and each  column represents one tissue sample. The relative miRNA expression is depicted according to  the color scale. Red indicates upregulation and green indicates downregulation. N1‐3 represents  NS tissue samples, whereas H1‐3 represents HS tissue samples. The differentially expressed  miRNAs were clearly separated into clusters. miRNA, microRNA; hsa‐miR, human microRNA; HS,  hypertrophic scar; NS, normal skin. 41 In the root, several functional and anatomical units could be recognized. Along the longitudinal axis, the root meristem forms a distal root tip, including stem cell niche, columella and lateral root cap, proximal meristem with a population of rapidly dividing cells and elongation zone where cells leaving the root meristem undergo rapid elongation and mature. 42 43 44 GENIST algorithm The MATLAB source code for GENIST is publically available at  https://github.com/madeluis/GENIST. For the detailed description of the procedure, see de Luis Balaguer et al., 2017, SI  (https://www.pnas.org/content/114/36/E7632/tab‐figures‐data)  45 GENIST algorithm The MATLAB source code for GENIST is publically available at  https://github.com/madeluis/GENIST. For the detailed description of the procedure, see de Luis Balaguer et al., 2017, SI  (https://www.pnas.org/content/114/36/E7632/tab‐figures‐data)  GENIST block diagram. GENIST is implemented in MATLAB, and is composed of  two consecutive steps, clustering and GRN inference. Clustering is performed  based on a spatial dataset. Each resulting cluster is independently processed by the GRN inference step, based on a temporal  dataset. 46 47 48 PAN subnetwork in the QC inferred with the 12 developmental time points of the Arabidopsis root. (A) Optimal configuration (combination of signs— activation or repression— of the regulations that were inferred with undefined signs, which best fits the data in the simulations of the equations) of the subnetwork of PAN and its downstream targets. (B  and C) Resulting expression values of PAN and its downstream targets, over time, after simulating the optimal configuration of the model. Simulations were run for 5 d and plots  are shown until all factors reached steady states in the WT and pan mutant simulations. (B)Model simulated with the fitted equation parameters. (C)Model simulated with the  PAN‐associated parameters set to zero to simulate a pan mutant situation. (D) Normalized expression values of PAN and its predicted downstream targets in Col‐0 wild type and  in pan mutant. Statistically significant changes of expression between the mutant and the wild type, *q < 0.05. In the WT simulation, all targets reached steady states by day 1 with subtle changes of expression during the transients (time length until expression values reach their steady  states). On the contrary, the pan mutant simulation showed that EIN3 and WIP4 presented high expression values during the transients and reached steady states at later stages  (days 3 and 4, respectively). These delayed responses and initial activations of EIN3 and WIP4 reflect the prediction that these genes are indirectly affected by PAN. Further, the  dynamics of our simulations depict that BRAVO, NTT, and WIP4 are, in our equations, connected through feedback loops. During the transient phase of the mutant simulation,  NTT and BRAVO show an exponential decay, which is consistent with the prediction that they activate each other in the absence of PAN. However, their steady states are not  immediately reached since they are activated by WIP4 and EIN3. Conversely, WIP4, which is repressed by a decaying NTT, shows high levels of expression. 49 50 51